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2011 Oral Presentations

2011 Oral Presentations

 

ORAL PRESENTATIONS SESSION I

Algal Biofuels

#66 Biogasification of Marine Algae Nannochloropsis Oculata
Samriddhi Buxy, Robert Diltz and Pratap Pullammanappallil, UF

Current interest in the algal derived biofuels focuses on the production of lipids for conversion to diesel-fuel substitutes. However, this approach requires overcoming several challenges including economical separation and extraction of the lipids followed by conversion of these to fuel. Another approach to biofuel production from algae will be via biogasification.

The objectives of this study were to investigate the growth yields and productivity of two species of marine algae, namely Nannochloropsis oculata and biogasification potential of this species. The marine algae species were grown in open raceways. Harvested algal cells were anaerobically digested in laboratory scale digesters to determine the extent of degradation, rate of degradation, methane production potential, and the effect of temperature,salinity and cell concentration on these biogasification parameters.

Florida with its warm climate – subtropical to the north and close to tropical in the south and long coastline offers tremendous potential for cultivation of marine algae biomass. Algae mainly consist of polysaccharides (included as cellulose, hemicelluloses, xylan and mannan), proteins, fatty acids, free amino acids, amines and nucleic acids in varying proportion and lipids. Marine algae have low lignin and cellulose content and known to accumulate lipids which makes it easy material to digest anaerobically and it should show high conversion rates and high biochemical
methane potential. Energy content of the biogas produced in this manner is comparable to that in the form of biodiesel per unit mass of algal cells. The algal cell slurry can be directly fed to the digester without the need for cell separation and very little energy is spent to separate the biogas product, therefore the net energy produced from biogasification is much higher.

#74 A Preliminary Estimation of the Algal Feedstock Production Potential of Tampa Bay Utilizing CO₂ Emissions and Wastewater Effluent
O. Kofi Dalrymple, Trina Halfhide, Innocent Udom, Ben Gilles, John Wolan, Qiong Zhang and Sarina Ergas, USF

Renewable energy derived from algal biomass is recognized as a potentially viable alternative to reduce dependence on fossil fuels and improve environmental sustainability. However, large-scale production of algae requires significant quantities of energy and water in upstream processes and the use of off-site carbon dioxide (CO₂). A possible synergistic solution to this challenge is to co-locate and integrate algal production with nutrient-rich municipal wastewater, as well as power plants to utilize CO₂ in flue gas. This approach has multiple benefits which include the reduction of eutrophication and CO₂ mitigation. Florida, and particularly the Tampa Bay area, has been identified as an ideal location for the development of algal feedstock and biofuel production because it receives significant sunshine, and demonstrates a relatively uniform seasonal evaporation loss than many other areas of the country. Most of Tampa Bay is supplied with electricity by the Tampa Electric Company (TEC), which has three power plants emitting approximately 17 million metric tons of CO₂ annually. To lessen the burden on scare freshwater resources, the power plants are making use of reclaimed water effluent from nearby wastewater treatment facilities to supplement their cooling needs. However, in some cases the effluent still requires further treatment to meet cooling water standards, hence increasing the cost of power generation.
This study is a preliminary quantification of the potential for microalgae feedstock production obtained by routing wastewater from the Howard F. Curren and City of Lakeland wastewater treatment facilities in Tampa and Lakeland respectively, and CO₂ from nearby TEC power plants. Our research has shown that a mixed culture of green algae, particularly Chlorella spp. can be successfully grown to commercial quantities on wastewater derived in Tampa when supplied with air containing more than 2% CO₂. In addition, algae have demonstrated the ability to naturally colonize effluent water in the wetland treatment system utilized by the City of Lakeland. A modeling analysis was performed to determine the mass of algae which can be supported by the nutrients (mainly nitrogen and phosphorous) available in the wastewater streams of both facilities. The model is based on the processes by which autotrophic green algae, in the presence of sunlight, take up CO₂, inorganic nitrogen (nitrates and/or ammonia), phosphorous, and certain micronutrients and fix them in biomass. It was guided by the kinetic data obtained for algal growth in the photobioreactors in operation at the University of South Florida.

In the analysis, only nutrients are assumed to be limited. All other parameters, such as land, CO₂ and sunlight are assumed to be abundantly available. It is also assumed that the temperature range in Tampa is suitable for algal growth year round. Assuming that the numerous technical challenges to achieving commercial-scale algal biofuel production can be met, the results presented here suggest that in excess of 1,600 metric tons per year of algal biomass can be produced. The oil volume was determined to be approximately 347,800 liters per year. By assuming 80% conversion efficiency, biodiesel production was estimated to be 278,200 liters per year.

#104 Novel Anaerobic/Algae Membrane Bioreactor (A2MBR) for Sustainable Recovery of Renewable Resources (Energy, Nutrients, Water) from Wastewater
Ana Prieto, Robert Bair, Ivy Cormier and Daniel Yeh, USF

Recovery of resources has been steadily growing in the wastewater treatment industry. Biosolids are land applied and reclaimed water is piped throughout many municipalities. Methane recovery for energy production is a common practice at anaerobic digestion facilities throughout the developed world. Most “recovery” efforts result from convenient byproducts of the removal process, and are not the focus of technology development. However, with rising energy costs, depletion of mineral reserves, increasing fertilizer costs, and increasing population stress on resources, society is on the cusp of a paradigm switch where recovery of resources from wastewater is not only sustainable but also makes good business sense. Focused efforts to recover renewable resources such as clean water, energy, nitrogen and phosphorus, from sewage are now becoming the basis of new technology innovation.

Algae cultivation in wastewater is one potential solution for nutrient and energy recovery. Algal biomass grown in wastewater can be used as a renewable fertilizer or fermented to produce biogas. Some species also produce significant quantities of lipids per dry cell weight, which can be turned into biofuel. Instead of losing nutrients through chemical precipitation or release to the atmosphere, as occurs in traditional wastewater treatment, incorporating algae into the process helps to close the nutrient loop and concentrate the energy source for subsequent use. Previous lab experiments suggested that the green microalgae Chlorella sorokiniana was able to rapidly adjust to the different effluents from treatment stages in a wastewater treatment plant. With dissolved nutrient concentration as high as 680 mg/l N and 34 mg/l P, this algae was able to grow at biomass concentration of 1.003 Kg/m3 as dry weight from the press filtrate of the sludge dewatering process. This outcome only confirms the great potential embedded in wastewater towards biofuel production from algae.

With the premise of the technology development for resource recovery, the effluent from a gas lift anaerobic membrane bioreactor (Gl-AnMBR) was used as a primary substrate for a biofuel producing algal photo-bioreactor. In this study, synthetic sewage was treated in a lab-scale AnMBR where waste organic matter is converted to biogas (methane and carbon dioxide) via hydrolysis, acidogenesis and methanogenesis. While capturing organic matter, particulates and even pathogens in the membrane, excess dissolved nutrients from the anaerobic process pass through to the algal photobioreactor, where they are assimilated by algae. Additionally, the produced biogas could be potentially recycled for membrane scrubbing (gas-lift) and further serves as carbon source for the algal culture. Results of the preliminary operation of the sequential AnMBR -algae photobioreactor will be shown in this presentation.

#107 Utilizing Native Algae for Biofuel Production
Ann C. Wilkie, UF

Photosynthetic algae represent a large and diverse group of organisms that have only a limited history of characterization and exploitation. The application of resource production from algae is relatively untapped, with the potential to produce fuels, food, fibers and nutraceuticals on a large scale. Methods to screen for indigenous species of algae have improved and can allow communities to prospect for algae suited to regional needs. When cultured locally, native algae are adapted to the prevailing regional abiotic and biotic factors. Native algae commonly inhabit local waste resources and pose no risk of becoming noxious invasives. Methods for culturing algae can utilize anthropogenic waste resources including wastewater nutrients and CO₂ from fossil fuel combustion. The majority of algae species have yet to be identified or characterized and the genetic diversity of these unknown species may offer significant but currently unknown benefits. Recalcitrant problems of culture stability, biomass density, harvesting, and product refining may be overcome by exploring native biological material. Selecting native algae with intrinsic characteristics amenable to bioresource production and waste mitigation is the most sustainable path forward for widespread algae-based bioresource development.

#123 Algenol’s Direct To Ethanol^® Technology: A Cyanobacteria-Based Photosynthetic Process for the Production of Ethanol
Ben McCool, Frank Jochem, Ken Spall, and Ron Chance, Algenol Biofuels

Algenol Biofuels’ DIRECT TO ETHANOL^® technology provides a highly efficient, cyanobacteria-based process for producing ethanol. This process has several advantages over alternative methods for ethanol production. It does not compete with food. It does not require arable land. It does not require large amounts of fresh water. Most importantly, it consumes large amounts of carbon dioxide with a large positive net energy balance, leading to a substantial reduction in net greenhouse gas emissions compared to gasoline. The technology involves over-expressing in cyanobacteria (blue-green algae) the genes for fermentation pathway enzymes found widely in nature. The resulting metabolically enhanced hybrid algae actively carry out photosynthesis and utilize carbon dioxide to make ethanol inside each algal cell. The ethanol diffuses through the cell wall into the culture medium and then a portion evaporates, along with water, into the headspace of an enclosed, sealed photobioreactor. The ethanol-water vapor is then condensed, collected as a liquid, and distilled into fuel grade ethanol. This talk will describe Algenol’s DIRECT TO ETHANOL^® technology, the carbon footprint for that technology, and highlight research and development efforts underway at Algenol and with our partners.

Energy Efficiency, Storage and Delivery

#42 A New Resonant DC Link for Single Phase Inverter
Anna Grishina, Haibing Hu, Dehua Zhang, Ahmadreza Amirahmadi, Issa Batarseh and John Shen, UCF

A new resonant DC link that allows for pulse- width- modulation (PWM) is presented in this digest. The proposed resonant DC link provides zero-voltage switching (ZVS) condition for the main devices by resonating the DC-link voltage to zero via three auxiliary switches and LC components. The operating principle and mode analysis are given. The simulation was carried out to verify the proposed soft switching technique. A 150W 120VAC single-phase prototype was built. The experimental results show that the soft switching for four main switches can be realized under different load conditions and the peak efficiency can reach 95.6%. The proposed DC link can be applied to both three-phase DC/AC inverter and DC/DC converters.

#65 ZVS-PWM High Frequency Grid Connected Micro-Inverter Without Additional Components
Qian Zhang, Dehua Zhang, Haibing Hu, John Shen and Issa Batarseh, UCF

A novel ZVS technique is proposed by operating the full-bridge DC/AC micro-inverter under BCM(Boundary Current Mode). The soft switching technique can be realized by control scheme without introducing additional switches. The basic operating principle and fundamental analysis for the inverter are described simply in the paper. To connect the micro-inverter with the grid, a peak current controller is applied to close the control loop. Simulation results using simulink verifies the practicable of that control scheme. A 150W prototype for single-phase inverter is built and some experiment results are provided. Further experiment is under working.

#68 High-Power High-Efficiency 13.56 MHz Class-E Power Amplifier for Wireless Power Transmission Systems
Raul Andres Chinga, UF

Wireless power systems are a rapid growing field which in a few years will become a standard alternative way to charge electronic devices and even electric cars. Energy consumption keeps growing and our sources are depleting. Energy has environmental, financial, and national security impact in the world. For this reason, it is critical that the power amplifier used for the wireless power transmission system is capable of achieving high efficiency to prevent unnecessary power from being wasted.

In this work, design method and characteristic of a high efficient Class-E power amplifier using GaN will be described. This amplifier is used as an inverter for wireless power transmission systems; with an operating frequency of 13.56 Mhz. The Class-E amplifier achieved an efficiency of more than 90% including the power consumption of the driving circuit (oscillator and gate driver), and achieving output power of 25W. This result indicates the Class-E presented in this work is suitable for high-efficient wireless power transmission systems.

#47 Modeling and Simulation of a Transport Membrane Condenser for Waste Heat Recovery
Cheng-Xian Lin, FIT

Due to its significance in energy efficiency improvement, waste heat recovery from industrial processes has received more and more attentions from researchers in recent years. Various technologies are currently being developed by researchers and engineers. Among the greatest challenges in this area is how to recover energy from low temperature or low grade waste heat, such as those possessed by combustion flue gas. To advance waste heat recovery technology, a better understanding of the underlined transport phenomena in flue gas heat exchange systems is required. In this work, a numerical study has been carried out to model and simulate the fluid flow and heat transfer with phase change in a transport membrane condenser (TMC), which can be used for recovering both sensible and latent and heat as well as water content from low-grade combustion flue gas. The flue gas investigated contains one condensable water vapor (H2O) and three noncondensable gases (CO₂, O₂, and N₂). The tube wall of TMC is made of a specifically designed porous ceramic material that is able to extract or separate condensate liquid from the flue gas. The numerical study was conducted within ranges of water and flue gas Reynolds numbers. Because of the complexity of physical processes in the transport membrane tube wall, a simplified multispecies transport model was developed for the turbulent heat transfer of flue gas. The governing equations include continuity, momentum, energy, turbulence transport, and species transport equations based on conservation laws. The condensation-evaporation process was simulated as a two-step chemical reaction with latent heat release. The RNG two-equation turbulence model was used for the turbulent flow. The governing equations were solved with finite volume based numerical method. Numerical results were compared with our laboratory-scale experimental data obtained in a parallel effort. It has been found that the developed multispecies transport model was able to predict the flue gas heat and mass transfer in the TMC tube bundle with fairly good accuracy. The heat and mass depletion decrease with the increase of the flue gas Reynolds numbers. Detailed results about flow velocity, temperature, turbulent kinetic energy, and mass fraction fields are also presented and discussed.

#1 Making Databases Green: An Energy-Aware DBMS Approach
Yicheng Tu, USF

Maintaining a sustainable society via technological innovations has been a major challenge for computing system design. In this project, we focus on the energy efficiency of an important type of computer applications, the database management systems (DBMS), which often consume a large portion of the computing resources and energy in modern data centers. The goal of this project is to design and implement a DBMS that enables significant energy conservation with graceful degradation of query processing performance. The project achieves its goal using the following approaches: (1) Dynamically exploit the energy-performance tradeoffs in DBMS as well as low-power modes of hardware systems for improved energy efficiency with performance guarantees; (2) Formulate the energy-efficient DBMS design as a feedback control problem, and adopt appropriate formal control techniques to achieve the desired performance and energy efficiency with theoretical analysis and guarantees; (3) Apply advanced multi-stage optimization methods to solve complex energy-aware storage management problems; (4) Coordinate various control and optimization loops in different layers of the DBMS for maximized energy savings and global system stability.

The impact of the project can be expected at two levels. At the society level, the reduction of energy consumption and CO₂ emission by implementing the proposed energy-aware DBMS can be substantial. Our research can benefit a large number of industrial sectors whose operations depend heavily on database-supported software such as online retailing systems, financial management software, and social networking platforms, by significantly lowering their electricity cost. At the education level, the research of this project trains PhD students in an interdisciplinary environment and enhances several courses by providing a rich set of application examples, software tools, and project opportunities.

Energy Policy

#12 Renewables and Energy Efficiency in the Body of Knowledge of Infrastructure Regulation
Sanford Berg, UF

Researchers, policy-makers, and educators have vast amounts of information available on sustainable energy via the internet. One UF-based resource found at www.regulationbodyofknowledge.org is available for Florida’s decision-makers but it also aims at assisting developing country governments in attracting and sustaining sound private investment in infrastructure by promoting the use of best practices and disseminating current trends. Sound engineering is necessary but not sufficient for the development and implementation of policies that promote environmental sustainability in the context of energy. The institutions of utility governance and regulatory oversight are central to the adoption of clean energy for the future. Feed-in tariffs, methodologies for comparing the costs of intermittent and dispatchable electricity generating technologies, incentives for off-grid investments, funding for energy conservation programs, and other issues are all under the purview of regulatory authorities-in Florida and around the world.

UF’s Public Utility Research Center has received funding to research and create links to the growing body of regulation and publications focused on energy efficiency and clean energy in key infrastructure sectors, focusing on how regulation can be used to enhance implementation of programs such as pollution control, renewable portfolio standards, carbon credits, and other policy initiatives. It will create a number of new Frequently Asked Questions focused on energy efficiency and clean energy with links to publications on these topics. The site will highlight examples of regulatory reforms in the area of clean energy, drawing from experiences across the world both in developing and developed countries. The Frequently Asked Questions and examples will emphasize countries in early stages of expanding their energy access, but the methodologies can be applied to developed countries as well. Beyond the World Bank Group, the BoKIR is used by training institutions for regulators to enable professionals to stay abreast of recent analytical developments and lessons emerging from cross-country studies.

In the future, we plan to create “study guides”. These would walk the trainer and student through the resources available on the BoKIR site; this initiative would integrate material associated with some commonly requested search items. In summary, the purpose of this presentation is to give energy analysts and policy-makers from Florida some exposure to this UF-based resource. In addition, we seek input from experts around the state in the design of support material that can be integrated into the web site. Of the total investment in power plants with private participation in developing countries, the share of investment directed to power plants using renewable resources rose from 27% in 2000-04 to 35% in 2005-09. There are lessons to be learned from the experiences of other countries. This website serves as a clearinghouse for material on the role of regulatory institutions in promoting cost-effective clean energy and energy efficiency.

#19 Innovations in Energy Policy Technology: How do Florida Cities and Counties Measure Up?
Jessica Terman and Richard Feiock, FSU

With the American Recovery and Reinvestment Act of 2009 (ARRA), the Department of Energy (DOE) has taken unprecedented steps to develop innovative strategies for alternative energy, heightened energy efficiencies, and the economic and workforce development involved in getting these projects off the ground. Rather than doing this is a centralized fashion at the federal level, local governments have the opportunity to apply for grants to implement one of 14 different energy efficiency strategies through the Energy Efficiency and Conservation Block Grant Program (EECBG). Cities and counties have received more than $1.8 million of the $2.8 billion available under the program. On a national scale, these are impressive numbers. However, for Floridians, the question is: How do local and county governments in Florida measure up to the rest of the country?
This presentation will compare Florida cities and counties against the rest of the country both in terms of their use of the EECBG program and how they incorporate energy policy into their governance strategies. For example, to what degrees are local and county governments applying for EECBG funds and at what rate are they actually implementing the projects using those funds? And, what types of projects are being implemented in comparison to other states? Similarly, we examine what extent local and county Florida governments recognize the connection between economic development and sustainability and promote this connection in their planning documents? These questions will address whether Florida is developing an infrastructure that will make it a national leader in the new age of energy sustainability and development.

We examine these questions using administrative data from DOE and a national survey distributed to all EECBG recipients. This research is useful to academics, public managers and elected officials alike because it highlights the strengths and identifies the weaknesses in Florida’s local government energy projects. Furthermore, in thinking about the importance of benchmarking and measuring performance, this will allow local policymakers to learn about where their governments and Florida as a whole stand in the bigger picture of energy innovation and development.

#59 Saving Energy and Jobs through Effective Revolving Loan Programs in the Residential Retrofit Sector
Hal Knowles, Pierce Jones and Craig Miller, UF

The Energy Efficiency and Conservation Block Grant (EECBG) program, authorized in the Energy Independence and Security Act of 2007 (EISA) and enabled through funding appropriated in the American Recovery and Reinvestment Act of 2009 (ARRA), is intended to assist local governments with strategic energy efficiency and conservation projects and programs designed to achieve the following:
Reduce fossil fuel emissions; Reduce the total energy use of the eligible entities; Improve energy efficiency in the transportation, building, and other appropriate sectors; and Create and retain jobs.

Many local governments are in the early stages of developing, launching, and administering innovative financing strategies in the hopes of leveraging this one-time infusion of EECBG stimulus funding into long-term, sustainable engines for economic growth in the energy efficiency and renewable energy sectors. This session will provide a brief overview and generate discussion about one of these financing innovations – revolving loan programs for residential energy efficiency retrofits.

The University of Florida Program for Resource Efficient Communities (UF/PREC) is actively developing a revolving loan program for Osceola County, Florida. This experience will be used to discuss the five key criteria of any successful revolving loan program: (1) solid financial underwriting; (2) accurate energy underwriting; (3) effective contractor engagement; (4) high quality loan servicing; and (5) rigorous energy measurement and verification (M&V).

More specifically, UF/PREC will bring its expertise in program development, public outreach, building professional training, and home performance analytics to explain how revolving loan programs can move beyond singularly addressing the financial barrier to consumers engaging in home energy retrofits. In addition to this conventional “first cost” barrier, effective loan programs also address related challenges such as lack of information, transaction costs, lack of confidence in savings, split incentives, length of paybacks, and other social and economic constraints.

#4 Expansion Planning for Combined Electricity and Natural Gas Systems
Alexey Sorokin, Qipeng Zheng and Panos Pardalos, UF & WVU

Natural gas is playing an increasingly important role in global energy market because of its environment friendly properties, especially for electricity generation. Natural gas mainly consists of methane, and when burnt it releases a large amount of energy and less green house gases than oil and coal. As the modernization/industrialization are covering the whole globe, people are more than ever addicted to energy. Combined cycle gas turbine plants supply people greener electricity, since the power generators are more efficient and release less greenhouse gases. Because of the increasing demand for natural gas, partially due to electricity generation, it is very important to study the natural gas transmission network expansion planning and LNG terminal location planning together. We consider transmission expansion problem for natural gas and electricity networks, as well as for LNG terminal location planning. The long-term planning horizon introduces uncertainties in demand for both natural gas and electricity. We employ Conditional Value-at-Risk to account for possible unsatisfied demand due to the lack of transmission capacity in the resulting system.

#6 The Effect of Renewable Portfolio Standards on State-Level Employment: An Ex Post Analysis
Colin Knapp, UF

Renewable Portfolio Standards (RPSs), programs which propose target levels of energy production or consumption that must come from renewable sources, have become a popular policy in state capitals across the country. As of 2010, 36 states and the District of Columbia had adopted programs which fall under the RPS umbrella. The reasons often cited for the adoption of these programs include; increasing the share of electricity generation from renewable sources, thus lowering greenhouse gas emissions and reducing the threat of global climate change; increasing security by moving towards national energy independence; and creating job growth by dedicating expenditures towards industries or technologies not currently represented within a state’s current mix of employment opportunities. These outcomes are supported by a vast ex ante literature which forecasts results using input-output analysis and economic forecasting models. The purpose of this paper is to approach the employment claim from a purely ex post perspective and measure the effect an RPS has on state-level employment. Initial results suggest a best-case scenario where every job created by an RPS is equally offset by job losses elsewhere in the state. Alternative specifications suggest a worsening employment situation with net job loss in those states which adopt an RPS. Additional results suggest that RPSs do not significantly increase the amount of energy generated from renewable sources in these states. This appears to be because the establishment of these guidelines is done with little enforcement of realistic and intermediate targets, making the policy an “empty promise”. The effectiveness of alternate programs, such as mandatory green power purchasing programs, suggests that the “field of dreams” mentality that surrounds RPSs may be misguided and other options might exist which help satisfy the same goals.

ORAL PRESENTATIONS SESSION II

Biomass

#83 U.S. Canada Clean Energy Partnerships in Bioenergy
Margaret Cullen, Consulate General of Canada

The objective of this paper is to discuss the projects and progress I have made in order to assist Canadian Companies, Universities and Research Institutions, form partnerships with Florida counterparts. Through these partnerships, assist in accelerating the development of the Clean Energy industry and track progress toward shared global energy goals. According to the International Energy Agency (IEA) 2011 Clean Energy Progress report: there is already ample evidence that when governments provide a sustained strategic framework for a clean energy future, the private sector invests rapidly in clean technologies. Working together, we can address the challenges the industry presents to achieve a sustainable energy future.

#89 Biomass Composition and Theoretical Ethanol Potential of Six Tall Grass Species Grown in Florida
Jeffrey Fedenko, John Erickson, Lynn Sollenberger, Robert Gilbert, Joao Vendramini, Kenneth Woodard and Zane Helsel, UF & Rutgers

Carbohydrate and lignin composition of feedstock materials are major factors in determining cellulosic ethanol potential. This study was conducted to quantify the sugars and lignin present in six potential biofuel grasses (elephantgrass, energycane, sweetcane, giant reed, giant miscanthus and sugarcane) across three sites in Florida for plant (2009) and first ratoon (2010) crops, and to calculate theoretical ethanol potential. Biomass composition was done according to the National Renewable Energy Laboratory procedure for the determination of lignin and structural carbohydrates. Giant miscanthus had significantly less glucose as a component of structural biomass (620 vs 680-710 mg g-1), but significantly more minor hemicellulose sugars (41 mg g-1 arabinose and 3.5 mg g-1 mannose) compared to most other species. Structural lignin concentrations varied by approximately three percentage units across species, and were generally highest in sweetcane and giant reed. Significant variability was found among species for sugars in nonstructural extractives, but sucrose was the predominant sugar. Sugarcane had the highest concentrations of extractive sugars, followed by energycane, then sweetcane, elephantgrass and giant reed, with giant miscanthus having the lowest concentrations of sugars as a component of extractives (150 to 750 mg g-1). Based on total structural and nonstructural sugars in the biomass, ethanol potentials as high as 16,500 L ha-1 were attainable for the plant crop, and 20,900 L ha-1 for the ratoon crop, and were comparable among sugarcane, energycane, sweetcane, and elephantgrass, but were generally less for giant reed and even less for giant miscanthus. Overall, elephantgrass and energycane were prime candidates for cellulosic conversion due to high yields, favorable fiber characteristics and lower lignin concentrations when compared with other high yielding species.

#113 Tri-reforming of Methane and CO₂: A Novel Concept for Catalytic Production of Solid Waste Syngas with Desired H₂/CO Ratios for Liquid Biofuels
Philip Saraneeyavongse, Devin Walker, John Wolan and John Kuhn, USF

This study focuses on upgrading the Municipal Solid Waste (MSW) syngas for the synthesis of liquid fuels by Fischer-Tropsch Synthesis (FTS). Typical biomass or MSW derived syngas H₂:CO is 1:1. This innovation allows for cost-effective one-step production of syngas in the required H₂:CO of 2:1 for use in the FTS. A novel gasification of MSW via a tri-reforming process involves a synergetic combination of CO₂ reforming, steam reforming, and partial oxidation of methane. To maximize the performance of the tri-reforming catalyst, an attempt to control oxygen mobility, thermal stability, dispersion of metal, resistance to coke formation, and strength of metal interaction with support is investigated by varying catalyst composition and synthesis parameters. These synthesis variables include Ce and Zr mixed oxide support ratios, amount of Mg and Ni loading, metal crystal size, and metal loading method. Catalytic performance testing to assess the activity, selectivity, and stability was performed using a home-built micro-reactor with a residual gas analyzing mass spectometer for gas analysis. Catalyst characterization techniques of Scanning Electron Microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), BET surface area measurements, X-ray Powder Diffraction (XRD), Temperature Programed Reduction (TPR), and Temperature-programmed Oxidation (TPO) were conducted to explain the effect of the synthesis parameters. This works highlights the performance of the tri-reforming catalyst and attempts to explain results through catalyst characterization.

#36 Enzymatic Hydrolysis of Pulp Dissolved in N methyl Morpholine Oxide (NMMO)
Subramanian Ramakrishnan, Gary Brodeur, John Telotte, Elizabeth Yau and John Collier, FAMU & FSU

The first step in the conversion process of biomass to biofuels or hydrogen lies in picking an environmentally friendly solvent which is capable of breaking up the crystalline microstructure of cellulose. Once the cellulose is in suspension, enzymes (cellulases) are added to the reactor to hydrolyze the cellulose to simple sugars that are then fermented by bacteria to biofuels. Till date, a number of solvents have been used for dissolving cellulose and for reprecipitating it by the addition of an anti-solvent thus making it a multi-stage process. In this work, it is shown that the number of processing steps can be reduced by directly carrying out the enzymatic hydrolysis in NMMO which is an excellent solvent for dissolving crystalline cellulose. Dissolving pulp of degree of polymerization 1160 is used as the substrate and Accellerase 1000 purchased from Genentech is the cellulase used. The rates of enzymatic hydrolysis and total sugars released are studied as a function of solution conditions – solution pH, temperature and enzyme loading. These studies reveal that the enzymes are active in NMMO and that the rates of hydrolysis of cellulose dissolved in NMMO are comparable to the rates of hydrolysis of regenerated cellulose suspended in aqueous buffer solutions. It will also be shown that high yields of sugars can be achieved by using a twin screw reactor for processing of high concentrations of the pulp (up to 15% w/w). Kinetics of hydrolysis at these high loadings will also be presented along with a mathematical model to describe the hydrolysis process.

#51 Comparative Life Cycle Assessment (LCA) Of Lignocellulosic Biomass Conversion Into Different Energy Products
Maria Pinilla, Qiong Zhang and Babu Joseph, USF

Biofuels have been identified as one of the key pathways for transforming the world’s energy supply. Many alternatives on biomass sources and biofuels conversion processes have been researched. Biofuels derived from cellulosic biomass have been found to offer considerable improvements when compared to biofuels produced from terrestrial food such as corn and soybeans.

In order to address the need of studying the environmental impacts of different pathways producing liquid fuels from cellulosic biomass, this study investigated the environmental impacts of two biofuels production systems. Both production systems involve the conversion of cellulosic biomass through thermochemical gasification. For both pathways, cellulosic biomass and water are fed into the process where gasification occurs at very high temperatures; then the obtained gas is cleaned up and conditioned as syngas. Syngas is converted to the energy products through Fisher-Tropsch (FTS) process. Finally different energy products are separated depending on their molecular weights.

The differences between two production systems are the process design and end products. The first pathway uses an approach of total heat and energy integration and produces ethanol and higher alcohols. This pathway does not require any outside sources of energy. The second pathway uses an approach of semi heat and energy integration and produces jet fuel, diesel, and heating oils. This pathway requires external natural gas and electricity as energy sources.

The data to develop these LCAs were obtained from different sources. To develop the LCA for the first pathway the information was obtained from a NREL report and several LCA databases. The LCA for the second pathway used data from LCA databases and simulation results from process modeling.
The environmental impacts were identified and analyzed using a LCA Software (GABI 4); and the impact assessment was performed based on the Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) methodology. Co-products such as charcoal from the biomass conversion processes are also considered in the analysis.

This study found that using the same amount of biomass, the first pathway produced more energy than the second pathway. It also demonstrated that the energy integration approach is promising when producing biofuels. In addition, the first pathway showed less environmental impacts than the second pathway, because of the vast amount of wastewater produced in the second pathway.

This study has also identified opportunities for improvement, such as different design of second pathway’s process so less wastewater is generated, and the treatment of wastewater on site and the recycling of treated wastewater.

#121 Development and Costing of an Integrated Biomass Gasification/Fischer-Tropsch Synthesis Process for Co-production of Transportation Fuels, Heat and Power
Ali T-Raissi, Nazim Muradov, Amit Gujar, Jong Baik, Nathaniel Garceau, Suzanne Fenton, David Block and Errol Hinkamp, UCF-FSEC

At the UCF-Florida Solar Energy Center, we have developed a two-step process for the co-production of “drop-in” transportation fuels, heat and power utilizing Florida grown biomass resources. In the first step, a pre-treated biomass feedstock such as pinewood pellets is co-fed (with steam) into an oxygen-blown gasifier continuously and converted to a gas rich in hydrogen and carbon mono-oxide. In the second step, the synthetic gas generated in the gasifer is fed to a especially designed Fischer-Tropsch synthesis (FTS) reactor and converted to a range of hydrocarbon fuels.
The Fischer-Tropsch reaction is highly exothermic and an effective heat transfer scheme is needed to ensure high product selectivity towards linear-chain liquid hydrocarbons. In this presentation, we report our progress to-date in designing, fabricating and testing a new and more efficient FTS reactor. The main features of the new reactor include: 1) replacement of the silicone carbide (SiC) particles added to the FTS catalyst with the highly conductive aluminum shots, and 2) re-design of the flow path of the reactants from axial to radial flow. The data obtained from a series of experimental runs with the combined biomass gasification and FT synthesis reactor operating in series will be presented and discussed. We will also present the results of a technoeconomic analysis and costing of a large-scale biomass-to-liquid fuel plant using AspenPlusTM chemical process simulation platform.

The Aspen generated output for a single set of non-optimized operating conditions was used to conduct order-of-magnitude estimates of the total plant cost and from that, the fully burdened cost of the fuel generated. Results of the analysis showed the technical and economical feasibility of the process with an overall plant efficiency of about 40% based on the tri-generation of fuel, heat and power. It was determined that the cost of biomass feedstock is the largest contributor to the cost of liquid fuel produced. At biomass cost of $163/ton and plant production capacity of 84,320 metric ton/yr, the cost of FT fuel would be about $7 per gallon. Using lower cost biomass feedstocks can reduce the fuel cost significantly.

Energy Systems

#30 Development of a Green Air Conditioning System based on a Rotary Engine Structure
Yiding Cao, FIT

A serious issue related to an A/C system is the refrigerant currently being used. It is estimated by the DOE that the global green house gas (GHG) emissions from refrigerants, such as R-134a or R-22, in 2050 could be equivalent up to 45% of total global CO₂ emissions in business-as-usual scenarios. For this reason, some countries such as the European Union have started to phase out these refrigerants. Therefore, it is very important to develop A/C systems with a zero Global Warming Potential (GWP) to reduce the associated GHG emissions and at the same time to lower energy consumption. Due to their low Global Warming Potential (GWP ‰¤ 1), the use of naturally existing gases as refrigerants has been sought after for many decades. However, the low Coefficient of Performance (COP) and bulky size of current technologies have limited their commercial uses.
To build a commercially viable gas-cycle A/C, it must: (1) Operate at sufficiently low speeds, not only for noise concern but also for reduction of frictional losses, which are proportional to the square of the speed; (2) Seamlessly integrate major parts with different functionalities into a compact system with reduced power consumption and size for further reduction of mechanical losses; (3) Operate in new cycles that have a relatively high COP; and (4) Reduce the losses in both gas cooler and low-temperature heat exchanger. To achieve these goals, a novel closed gas-cycle A/C system based on the rotary configuration of a Wankel engine has been under development at FIU for the past two years. As a true green A/C, the new A/C uses air/nitrogen (GWP = 0) as the working fluid and eliminates all related green house gas emissions. An A/C model has been built based on the body structure of a two-rotor rotary engine, having a displacement volume of approximately 573 cc for each rotor. The use of the rotary engine structure is due to its unique configuration for integration of the compression, cooling, and expansion functionalities of an A/C system. For efficient and compact cooling, multiple cooling chambers are employed before the expansion. For simplicity and reduced power consumption, a rotary valve system and the related pulley system for valve timing have been designed and fabricated for the cooling chambers. The A/C model is currently being tested for feasibility study. The objectives of this presentation are to discuss the progress being made and the difficulties encountered, as well as the future undertaking for the green A/C development at FIU.

#43 LPG (Liquid Propane Gas) and DME (Dimethylether) Indirect And Direct Injection System in Liquid Phase
Danilo Gardi, ENSIDA R&D

Presentation of LPG (Liquid Propane Gas) and DME (Dimethylether) indirect and direct injection system in liquid phase, to be installed on Otto Cycle and Diesel cycle engines

Improvement of the existing electronic engine management for LPG and DME injection systems

Solution to problems related with LPG and DME fuels contaminants, particularly for fuel transfer systems and related filtration

Design and Development of mechanical parts related with DME common rail injection systems for diesel engines

Final consideration about LPG and DME conversions: economic impact and environment impact

#63 Steam Iron Process: Examination of Regenerative Cycling
Richard Stehle, Michael Bobek and David Hahn, UF

The steam iron process is re-emerging as a method to separate and isolate hydrogen, in a more renewable way than the methods currently used. In order to examine the fundamental characteristics of this process, a monolithic reactor was used to carefully control experimental conditions. Building off of previous work that examined kinetic rates for oxidation, recent focus was placed on the effects of redox cycling and cycle optimization, with respect to the stability of the iron/iron-oxide interface. Since this process involves a surface reaction and the instabilities tend to occur at the iron/iron-oxide interface, limiting the reaction to the outermost layer of oxide and limiting diffusion are ways to optimize the process. For these reasons, a short cycle duration was examined in an attempt to limit the extent of each step to the highest rates and most transient regimes. The oxide structure was examined via SEM and EDS imaging, with focus on the oxygen content in the iron and how it changes over many cycles, and between the oxidation and reduction step.

#61 Florida’s Energy-from-Waste Industry: Utilizing One of Florida’s Indigenous Fuel Sources
Joseph Treshler, Covanta Energy

Florida is the nation’s leader in recovering energy from municipal solid waste (MSW). MSW is included in the State’s definition of Biomass. The State’s 11 Energy-from-Waste (EfW) facilities currently generate about 520 megawatts of base load electricity, using a fuel that is indigenous, abundant, price-stable and renewable. Unfortunately, current Florida energy policy places an undue burden on Florida communities, as they seek a stable path to explore, expand and/or continue offering EfW services.

EfW is the preferred/primary method of disposal for the non-recycled portion of the waste stream in many of Florida densely populated counties, and, is virtually the only practical means available to manage this waste on a local basis. Moreover, EfW is viewed by the USEPA and by the European Union as a preferable management method when compared to the long-term environmental liabilities of raw waste landfills.
The ability of Florida counties, to continue utilizing EfW depends in great part on the future direction of Florida energy policy. Revenue to operate an EfW facility is derived from two basic sources: the sale of electricity and the tipping fees charged (ultimately to consumers/county taxpayers) to process the waste. Under Florida’s current energy regulatory regime, EfW facilities must sell their electricity onto the Florida electrical transmission grid at avoided cost rates. The formulas for calculating avoided cost results in imbalanced pricing that undercuts EfW’s environmental superiority as a waste management process and unintentionally favors low-cost-competition from raw waste landfills making it extremely difficult for Florida counties to offer EfW services.

Nominally, Florida’s “avoided cost” rules are meant to ensure that ratepayers get electricity at the lowest possible cost. The tragedy is that this behavior prevents the citizens of Florida from realizing the many environmental and economic benefits derived from the renewable electricity EfW can generation while properly managing a community’s non-recyclable waste.

Finally, the economic potential of EfW cannot be understated. Jobs at EfW facilities cannot be outsourced to another county or state. The economic impact of building just one new 1,500 ton-per-day EfW facility would create 250 direct construction jobs over three years (and 625 secondary construction jobs) as well as 115 direct and secondary permanent jobs once operation commences. The permanent economic impact of each new facility to its local community – through payroll and the purchase of needed goods and supplies – is significant. The 2009 Navigant Consulting report for the FLPSC estimated that EfW could add 1,330 to 2,273 new MWs of base load generating capacity to the Florida transmission grid by 2020. If fully exploited, the Navigant estimate could mean the potential addition of 10 to 20 new EfW facilities in the state, creating more than 2,000 highly paid permanent and sustainable jobs.

Going forward, Florida energy policy must take into account the long-term environmental and economic benefits of EfW and provide for a fair and balanced pricing that recognizes these significant community benefits as part of the state’s renewable energy policy.

#46 Comparison of Mesophilic and Thermophilic Two Stage Anaerobic Digestion of Municipal Organic Solid Waste
Gayathri Ram Mohan, Patrick Dube and Pratap Pullammanappallil, UF

Anaerobic digestion of municipal solid waste is an economically and commercially viable solution to two vital problems that have been a major concern to the present generation: rapid depletion of fossil fuels and the drastic impact of increased pollution on the environment. Anaerobic digestion of municipal solid wastes, a decentralized energy production system, provides a beneficial way of waste management in that wastes are diverted from being dumped in landfills and are instead used to produce renewable energy in the form of biogas, a valuable biofuel. There are various reactor designs that are currently available for anaerobic digestion of solid organic wastes and these include batch and continuously fed single-stage, two-stage and hybrid- two-stage systems , consisting of leach bed, stirred tank and packed or fluidized bed reactors. There are two process operating temperature regimes: mesophilic (32 – 40 degree C) and thermophilic (50 – 58 degree C). Most commercial systems are operated at mesophilic temperatures due to larger diversity of microbial communities, its perceived process stability and reduced parasitic energy consumption. However, thermophilic temperatures offer process advantages like greater reaction rates and increased pathogen inactivation. In this paper, we compared the performance of a batch-fed hybrid two stage digestion system at thermophilic (55 á´¼C) and mesophilic (37 á´¼C) temperatures. The system was fed a synthetic waste mix that is representative of source separated organic wastes collected from residential areas. The hybrid system consisted of a 5L leach bed reactor into which the solid waste was loaded and 12 L packed bed anaerobic filter reactor. The system was operated as follows: 500 ml of the percolate from the leach-bed reactor was transferred to the anaerobic filter and 500 ml of mixed liquor from the filter was in turn transferred to the leach bed daily. Two experiments were carried out at each temperature and these were monitored for sCOD, nutrient content, pH, biogas production and composition. Results from the two temperature regimes were compared and analyzed. Each experiment was carried out for ~15-20 days. It was found that the methane yield and extent of solubilization of the solid waste was higher at mesophilic conditions. However, the % sCOD reduction was higher in thermophilic runs: 85%, than in mesophilic runs: 65%. pH reached neutral after ~8 days in thermophilic runs, while it took 12 days in mesophilic runs. Biogas composition reached 55% CH₄, 40% CO₂ and thereafter stabilized at this point much earlier in thermophilic runs as compared to mesophilic runs. The %solids reduction in thermophilic experiments was 42% while in mesophilic experiments it was determined to be 40.5%.

#99 Environmental Study of Solid Waste Collection
Mousa Maimoun and Debra Reinhart, UCF

This research is an in-depth environmental analysis of waste collection vehicles. In order to reduce emissions to the atmosphere, more companies are investigating alternative fuels technologies such as natural gas, biofuels (bio-gas and bio-diesel), and hybrid electric technology. This study will set as a baseline for the use of alternative fuels for waste collection vehicles. Throughout the study, we will evaluate the life-cycle emissions associated with the use of alternative fuels for waste collection vehicles. Moreover, this study will take a closer look at diesel-fueled refuse trucks trying to compare the actual driving cycle emissions with other ideal operating conditions. The main goal of such a comparison is to demonstrate the environmental impact of the actual operating conditions of waste collection vehicles. Finally, a qualitative comparison between alternative fuels will be performed. The analysis consists of multifactorial assessment of environmental, financial, operational, safety, and strategic issues associated with the use of alternative fuel technologies. The main purpose of such a comparison is to assess different factors that affect the selection of a future fuel for waste collection vehicles. Thus, recommending a future fuel for waste collection vehicles.

Ocean, Carbon Capture, and Nuclear Energy

#3 Marine Hydrokinetic Energy in Florida: Toward Implementation
Howard Hanson, Susan Skemp, Gabriel Alsenas, Camille Coley and William Baxley, FAU

Marine renewable energy (MRE) is poised to become an important component of a diversified energy portfolio for the nation’s future. Like other renewable energy resources, MRE resources are regional in nature, and in Florida they are embodied in the energy of the Florida Current and in the thermocline. The Southeast National Marine Renewable Energy Center, one of three such national centers in the U.S., each associated with regional resources, is working to advance the technology of MRE resource recovery and its implementation in Florida.

Although the resources are regional, they offer considerable potential. For example, the U.S. Department of Energy and the National Renewable Energy Laboratory have developed a method for estimating the potential of offshore wind power, and it appears that there is some 4,000 GW of potential over the U.S. Outer Continental Shelf. The same method, suitably adapted for the case of open-ocean currents (which involve the same fundamental physics as power from the wind), yields a potential of 200 GW of base-load power in the reach of the Florida Current between the Dry Tortugas and Fort Pierce. An additional 200 GW of base-load power potential appears to be stored in the oceanic temperature stratification in the region. Moreover, this huge potential – 10% of offshore wind and some 40% of the US national generating capacity – is located within close proximity to a top-five load center, the Southeast Florida metroplex.

Just as is the case with offshore wind, however, realizing all of this potential is both unrealistic and unlikely. Not only are the technology requirements overwhelming, but the environmental implications are cause for concern. Yet recovering only 1% of this total potential seems both technologically feasible and economically attractive as well as environmentally reasonable – and the resulting 4 GW would serve all of Southeast Florida by allowing replacement of fossil fuel generation and obviating the need for new traditional generating stations.

By negotiating the maze of regulatory requirements and providing laboratory and at-sea testing capabilities for industry, the Southeast National Center is charting a course to expedite future commercial development of these clean and sustainable MRE resources.

#9 Blade Vortex Interaction in Uni-directional Impulse Turbines for Wave Energy
Carlos Velez, Justin Ladd and Othmane Khoungui, UCF

Uni-directional impulse turbines are used for the extraction of wave energy by converting oscillating air flow generated by waves into uni-directional rotational energy. The symmetric airfoil design requires a large camber, in order to function in bi-directional flow, which creates a large boundary layer seperation region towards the trailing edge of the blade. A three-dimensional, viscous, transient turbulent CFD model with rotating reference frame is created to model the blade vortex interaction (BVI) which occurs during transient bi-directional air flow. Various LES models are compared to determine an adequate turbulence model to resolve the vortices created on the blade trailing edge. A study of the adverse effects of this BVI is conducted and a novel blade jet technique is introduced to prevent the seperation of air flow from the trailing edge of the blade. Results show strong stresses arise from BVI during bi-directional transitional flow and the effectiveness of the blade jet technique in diminishing flow seperation is demonstrated.

#62 Hydrovolts Offers New In-Stream Hydrokinetic Turbines
Burton Hamner and Colin Mcrae, Hydrovolt, Hydrovolts Inc

Hydrokinetics is the term used to describe devices that utilize moving water to generate electricity. A hydrokinetic device’s ability to produce electricity is governed by the speed of the water flow without the use of dams or other man made barriers.

Hydrovolts’ proprietary turbines leverage the immense energy of moving water. In this inherently environmentally friendly design, the amount of energy available for capture is directly proportional to the turbine’s “water footprint”, or amount of water entering the device.
Hydrovolts turbines are based on a horizontal rotational axis oriented perpendicular to the direction of water flow. This allows access to a much greater fraction of the canal cross-section than axis-parallel (pipe) or vertical-axis designs, and creates high efficiency without significantly affecting water flow. The design is:

Submersible: Hydrovolts turbine’s generators are attached to the unit, so that it can generate energy either floating on the water’s surface or submerged within the flow.

Neutrally buoyant: The turbine’s buoyancy can be adjusted to generate power where the water velocity is greatest. Once adjusted, the turbine floats in place, and thus automatically tracks varying water levels.

Safe: Unlike the slash of a propeller, Hydrovolts turbine blades spin with the water current, generating force from drag. This makes the turbine fish-friendly.
Scalable: Turbines can be installed singly or in chains down the length of a canal. Turbine density and therefore energy generation is only determined by canal’s speed and size.

Modular Generator Endcaps let you switch the blades to take advantage of a site’s flow characteristics. Unlike other micro-turbines, Hydrovolt’s generator frame design is specifically engineered to easily accommodate different types of rotor blades, allowing for a choice of blade that optimizes the amount of power at an individual site.

The Patent-Pending Flipwing Rotor is a breakthrough in mechanical innovation for hydropower generation. The hinged blades or paddles are pushed by the current against the center shaft driving the rotation. As the blades begin their reverse upstream stroke they flip open backwards and present only their edge to the current. This eliminates almost all resistance and provides a pressure differential across the axis of about 95%.

Hydrovolts technology can be applied to a wide range of sites from irrigation canals with limited environmental concerns or permitting requirements, easy access and predictable water flows, to large fast rivers and tidal channels able to generate utility-scale renewable energy. Hydrovolts turbines have been engineered for easy “drop-in- installation” no dams or construction needed. The floating turbine is held in place by mooring lines. This allows them to be easily deployed and rapidly generating energy from waves, river and tidal currents for remote communities and households in developing countries. Military units of expeditionary forces can use man-portable backpack size turbines to produce power in remote deployment locations. Oceanographers can generate enough energy to charge battery-powered observation systems by submerging larger turbines in the slow, deep ocean currents near their sensors.

#7 Carbon Capture and Sequestration: Opportunities in Florida
Jeffrey Cunningham, Yogi Goswami, Mark Stewart and Maya Trotz, USF

It has been proposed that carbon dioxide (CO2) could be captured from large stationary sources, such as fossil-fuel-fired power plants, and then stored underground in geologic repositories, as a means of removing CO2 from the atmosphere and thereby mitigating global climate change. This proposed technology is often called “carbon capture and storage,” or CCS. Our team at USF is working to investigate three aspects of CCS. First, we are developing new technologies to capture CO2, which may be more cost-effective than existing technologies. Second, we are conducting a geologic investigation of what subsurface formations in Florida might be most suitable for CO2 storage. Third, we are developing models to predict how CO2 will behave when injected underground, including geochemical models to predict what chemical reactions will occur when CO2 dissolves into the native brine of deep saline aquifers. In this presentation, we will give an overview of our work from the past year and will summarize some of our most important recent findings. Our work so far suggests that CCS in Florida appears feasible, which may provide economic advantages pending the outcome of federal legislation to control nationwide emissions of CO2 and other greenhouse gases.

The main objective of carbon capture part of this research is to develop a simple and cost-effective method that captures CO2 from power plant flue gas using calcium oxide as a sorbent. A method has been developed to deposit films of calcium oxide on ceramic fabrics, which can be used directly in a reactor to capture CO2. Results show that the developed calcium oxide sorbent can be used for reversible CO2 capture, with performance showing no decrease in efficiency even after 13 capture-release cycles.

As a result of the modeling capabilities developed in this FESC project, USF researchers are now collaborating with a major electric utility in Florida to apply for a permit to perform a CCS demonstration project. A well has been drilled at the site of a coal-fired power plant to a depth of 8000 feet (2.4 km) below ground surface. This well may be used for the disposal of process wastewater from the power plant, for the injection of CO2 captured at the plant, or for the co-injection of wastewater and CO2, pending the approval of current and planned permit applications.

Modeling work performed in support of this proposed CCS project has resulted in at least three important findings so far. First, using appropriate vertical heterogeneity (derived from well data) in the model greatly reduces the predicted buoyancy effects of the CO2 plume, thereby increasing the predicted storage capacity of the formation. Second, alternating the injection of supercritical CO2 and wastewater greatly enhances the dissolution of CO2 into a stable dissolved phase, thereby reducing buoyancy effects and making caprock integrity much less important to successful sequestration. Third, there is a risk of clogging the injection well or the geologic repository if injected wastewater is saturated with respect to certain mineral phases, but the co-injection of CO2 with wastewater can help to lower the pH of the wastewater and thereby prevent mineral precipitation.

#33 Metallic Nuclear Fuel Research at University of Central Florida
Ke Huang, Emmanuel Perez, Youngjoo Park, Ashley Ewh and Yongho Sohn, UCF

U-Zr metallic fuel with stainless steel cladding has been developed for generation IV sodium fast reactor. The fuel cladding interaction (FCI), induced by interdiffusion of components, has deleterious effects on the system because it thins the cladding and produces phases with relative low melting point. U-Mo metallic fuel with Al alloy cladding is being developed as a low enrichment uranium fuel under the program of Reduced Enrichment for Research and Test Reactor (RERTR). Significant interactions have been observed between the U-Mo fuel and the Al matrix during fuel processing and irradiation. In order to understand the diffusion behavior of components in the fuel and cladding materials and to explore potential barrier materials to reduce the FCI, solid-to-solid diffusion study in selected binary and ternary systems of uranium were conducted, including U vs. Fe, U-Zr vs. Fe, U-Zr vs. Mo, U vs. Mo, U-Mo vs. Al and U-Mo vs. X (X=Zr, Mo, and Nb). The scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron probe microanalysis (EPMA) were applied to analyze the microstructures, phase constituents and concentration profiles in the interdiffusion zone.

In U vs. Fe diffusion couples, two intermetallic phases U6Fe and UFe2 developed, and U6Fe phase was much thicker than UFe2. Eextrinsic and intrinsic growth constants, and integrated interdiffusion coefficients for each phase were calculated. For U-Zr vs. Fe diffusion couples, layers structure with complex mixture of multiple phases developed. All phases existing in the interdiffusion zone were identified and the diffusion paths were also determined. Based on the average thickness of each layer, the growth constants were calculated. For U vs. Mo diffusion couples, interdiffusion coefficients as functions of temperature and Mo composition were calculated. The intrinsic diffusion coefficients of U and Mo at the marker composition were also determined, and were employed to estimate the thermodynamic factor of U-Mo alloy, mobility and vacancy wind effect of U and Mo according to Manning’s description. In U-Mo vs. Al diffusion couples, interdiffusion zone showed a stratified microstructure that varied of finely dispersed UAl3, UAl4, U6Mo4Al43 and UMo2Al20 phases while the average composition throughout the interdiffusion zone remained constant at approximately 80 at.% Al. To reduce the FCIs, refractory materials (such as Zr, Mo, Nb) are considered to work as barrier layer between fuel and cladding materials. Study in U-Mo vs. X (X=Zr, Mo, and Nb) and U-Zr vs. Mo diffusion couples is in progress.

ORAL PRESENTATIONS SESSION III

Biomass

#79 Establishing a Sustainable Feedstock Industry in the Southeast
Steven Webster, Mathews-Webster Consulting

The presentation will discuss the components needed to establish a sustainable feedstock industry in the Southeast, focusing on biofuels. The components include determining the profitability of feedstock crops, economics of a crushing/processing facility, and identifying markets and buyers appropriate for crops and processing technologies.

While extensive research on biofuels already exists, there is very little real-world data. Information to be presented is based on actual data from the2010 Florida renewable harvest, which was the first commercial scale harvest in Florida of non-woody crops. This is real-world information not previously available from any source.

The presentation will include a review of the current market, market distortions, reasons behind the slow growth of “feedstock to fuel” business, and conclude with an outline of a new initiative to increase production, a region-wide association that will link all segments of the biofuel industry.

#26 Combined Cooling, Heat, Power, and Biofuel from Biomass and Solid Waste
William Lear, Jacob Chung, Elango Balu, Minki Kim and Uisung Lee, UF

The goal of this project is to provide the underlying research and demonstration of a novel technology which would enable the economic utilization of dispersed biomass and solid waste resources to produce electric power, cooling, heat, and transportation fuels. The project is divided into two parts, an advanced high-temperature steam gasification system and an integrated novel energy conversion system known as the Power, Water Extraction, and Refrigeration (PoWER) system.
Biomass gasification is the process of converting carbonaceous material to a synthesis gas consisting primarily of hydrogen, carbon monoxide and methane, which can be burned directly in conventional and unconventional engines and gas turbines. To simulate the gasification process, the first step was to develop an equilibrium model which predicts gasifier temperature, heating value and syngas composition. These results were compared to our gasification experiments which were performed with an integrated IC engine. Experiments using four biomass feedstocks were conducted, and the measured engine efficiencies were quite comparable to those using gasoline and natural gas.

The model for a completely self-sustained gasification process with no external heat source was also developed by recirculating a portion of the hydrogen from the syngas. About 60% of the hydrogen from the syngas would be required to make a self-supporting 2000°C steam gasifier, assuming liquid water as feedstock. The envisioned integration of the gasifier and PoWER systems would provide moderate temperature steam, requiring far less hydrogen to be extracted from the syngas, nominally 10%.

SCZE ceramic membranes for hydrogen separation were studied to enhance the H2 yield. The water-gas shift (WGS) reaction would also convert CO into CO2 and provide additional H2, important if liquid fuel is the ultimate product rather than direct power. For the fabrication, Polycrystalline SrCeO3-δ and SrCe0.9Eu0.1O3-´ powders were prepared with conventional solid-state reaction by mixing stoichiometric amounts of SrCO3 (99.9%), CeO2 (99.9%) and Eu2O3 (99.9%) powders, followed by ball milling and calcining at 1300°C. A NiO-SrCeO3-δ tubular support was fabricated using tape-casting (Pro-Cast) followed by a rolling process. The tubular support was sealed at one end and pre-sintered. SrCe0.9Eu0.1O3-δ was coated on the inner side of the pre-sintered support. Experimentation will follow to evaluate the membrane performance characteristics.

To enable syngas characterization, we have focused on the installation of a well-characterized commercial gas turbine engine as a step towards utilization of the syngas in the PoWER engine. The rig is based on a Capstone C60- system, designed for multiple fuel sources, including methane, syngas, and a LPP Combustion artificial fuel skid. A base test has been done with methane, and each step of loaded operation has been scheduled and performed with a 200kW load bank (Merlin Simplex). Current development efforts focus on a flexible fuel supply system to allow the fuel composition to be varied parametrically to simulate a wide range of syngas conditions. In addition, continuing parallel activity includes integrated system modeling, PoWER (turbine), Absorption Refrigeration, and HiTS (gasifier). This is expected to result in significant improvements in the cost, emissions, feedstock flexibility, and water requirements, all in a relatively compact, modular plant system. This in turn will enable much greater utilization of renewable energy supplies, helping the development of a sustainable energy supply infrastructure.

#29 Bioenergy and Bio-based Materials from Lignocelluloses
Zhaohui Tong, Lonnie Ingram and Letian Wang, UF

To simultaneously consider preserving our natural resources and alleviating the depletion of petroleum oil, a shift of renewable resources to produce fuel and value-added chemicals is becoming a significant sustainable development approach. In this project, lignocelluloses biomass (sugar bagasse) has been investigated as a potential feedstock to produce renewable fuels (such as ethanol) and biomaterials (such as biodegradable composite). Firstly, we will brief discuss the single process to produce ethanol from sugarcane bagasse. Then, we present our current research to produce poly (lactic acid) (PLA) composites reinforced by sugarcane bagasse residues from different bioprocessing stages via twin-extrusion. These composites are not only 100% renewable and biodegradable, but also have the competitive cost in comparison with petroleum-based composites. The sugarcane bagasse residues (30 wt.%), containing different content of fibers and all the remaining lignin, were used to prepare lignocelluloses reinforced PLA composite with desirable physical and chemical properties. The varieties of different bagasse residues include the composition, particle size and its surface reactivity during the chemical and biological (enzymes, microbes) treatments that the biomass is subjected to. The effect of these varieties on the morphologies, thermal properties, mechanical properties and the molecular weight of PLA composites was studied as well. Furthermore, a coupling agent (Desmodur® VKS 20) was used to increase the interfacial bonding of PLA with lignocelluloses. Its effect on the properties of PLA composites was also under investigation.

#39 Engineering Thermotolerant Bacillus Coagulans for Production of D-lactate from Lignocellulosic Biomass
Qingzhao Wang, Lonnie Ingram and K T Shanmugam Maria Pinilla, Qiong Zhang and Babu Joseph, UF

Lactic acid is an attractive, renewable chemical for production of bio-based plastics (polylactic acid, PLA), but commercial production currently uses food-based sources of sugar as a feedstock. Pure optical isomers of lactate needed for PLA are typically produced by microbial fermentation of sugars at temperatures below 40°C. Bacillus coagulans produces (L+)-lactate as a primary fermentation product and grows optimally at 50°C and pH 5, conditions that are optimal for activity of commercial fungal cellulases. This strain was engineered to produce D(-)-lactate by deleting the native ldh (L-lactate dehydrogenase) and alsS (acetolactate synthase) genes to impede anaerobic growth, followed by growth-based selection to isolate suppressor mutants that restored growth. One of these, strain QZ19, produced about 90 g L-1 of optically pure D (-)-lactic acid from glucose in <48 hours. By using QZ19 for simultaneous saccharification and fermentation of cellulose to D-lactate (50ºC and pH 5.0), the cellulase usage could be reduced to 1/3 that required for equivalent fermentations by mesophilic lactic acid bacteria. Together, the native B. coagulans and the QZ19 derivative can be used to produce either L(+) or D(-) optical isomers of lactic acid (respectively) at high titers and yields from non-food carbohydrates such as cellulose and hemicellulose (xylose).

#73 Characterization of Invasive Potential of Naturalized Populations and Cultivated Types of Elephantgrass, A Bioenergy Species for Florida
Lynn Sollenberger, Kenneth Woodard, Joao Vendramini, Christine Chase, Yolanda Lopez, Maria Gallo, Jeff Seib, Ken Langeland and Hermes Gerardo, UF

Elephantgrass (Pennisetum purpureum Schum.) is a candidate bioenergy grass in the southern Gulf Coast Region, but it is also a weed in sugarcane (Saccharum sp.) fields, rights of ways, and natural areas of central and southern Florida. It is not known if naturalized populations (NPs) and cultivated elephantgrass types are similar genetically and in characteristics related to invasiveness. This information is needed to inform decision making regarding use of elephantgrass as a bioenergy crop in the region. Objectives were to compare 10 elephantgrass NPs collected throughout Florida with six cultivated types in terms of: i) morphology, growth characteristics, and mechanisms of vegetative spread; ii) flowering behavior and seedling recruitment; and iii) genetic relatedness. Elephantgrasses were planted in replicated 2- by 5-m plots at locations in North and South Florida in 2008. In September 2009 and 2010, cultivated types were taller (3.8 vs. 3.4 m), had longer (92 vs. 62 cm) and wider (35 vs. 20 mm) leaves, and had fewer tillers per plant (32 vs. 38) but greater tiller mass (270 vs. 160 g per tiller) than NPs. Cultivated types were more upright growing and less likely to lodge. Among all grasses, there was a 56-d range in initiation of flowering, with cultivated types flowering later than NPs. One cultivated type did not flower in either year, and another did not flower in Year 2 when the first freeze occurred on 2 December (32 d earlier than in Year 1). Random amplification of polymorphic DNA (RAPDs) and simple sequence repeat (SSRs) markers, used to assess the genetic relatedness between NPs and cultivated elephantgrasses, generated phylogenetic trees that clearly separated the two groups of entries. This clear distinction between cultivated elephantgrasses and NPs indicates that these markers may be useful in the future to efficiently select for parents in a bioenergy breeding program. Additionally, our data indicate that among elephantgrass types there is a wide range in plant growth characteristics and traits associated with potential invasiveness. Therefore, it should be possible to select types with reduced invasive potential for use in bioenergy production systems.

Energy Storage & Delivery

#40 Towards Solid-State Li Ion Batteries with Semiconductor Nanowire Anodes
Nicholas Rudawski, Jeong-Hyun Cho, Binh Tran, Guangyu Chai, Isaiah Oladeji, Mark Orazem, S. Picraux and Kevin Jones, UF

Li ion battery (LIB) technology is promising for use in energy storage for mobile devices and transportation applications. However, significant challenges must be addressed prior to implementation. Specifically, the safety of LIBs using organic solvent-based liquid electrolytes (LEs) is of concern under certain operating conditions. Likewise, current LIB electrode materials have low specific capacities on the order of ~200 mAh/g and can suffer from poor cyclability. Replacing LEs with solid-state electrolytes (SSEs) offers the potential for safer LIBs, but the use of SSEs has been reported only with lower performance electrode materials. Therefore, developing LIBs with SSEs and high specific capacity and cyclability electrodes is of great interest. A potential solution is the development of an all solid-state LIB with semiconductor nanowire (NW) electrodes. It is known that semiconductor NW electrodes in half-cell configurations with LEs exhibit specific capacities several times greater than current LIB electrode materials with excellent cyclability for a wide range of cycling rates, yet the performance of NW electrodes in contact with SSEs has never been investigated. Thus, it is intriguing to consider developing LIBs with SSEs and semiconductor NW electrodes to create cells that are safer than those with liquid electrolytes and have excellent specific energy, capacity, and cyclability. Ge, in particular, is attractive as an electrode material in high power applications since it has high Li+ diffusivity.

For this work, Ge NWs were grown directly on polished stainless steel (SS) substrates using the Au-catalyzed vapor-liquid-solid growth method. Subsequently, the samples were attached to SS handle sheets using conductive Ni paste and coated with LiyAl1-xGaxSPO4 SSE layers of thickness 0.2 – 1.0 ¼m using an electroless spray deposition method. The samples were fabricated into air-tight pouch cells for electrochemical testing in an Ar atmosphere using single-ply polypropylene separators and 1.0 M LiPF6 in 1:1 (by volume) ethylene carbonate:dimethyl carbonate LE with the Ge NWs on the SS substrate as one electrode and Li metal foil as the other electrode (half-cell configuration). The electrochemical properties of the cells were evaluated with galvanostatic cycling and electrochemical impedance spectroscopy in a three-electrode configuration with the Ge NWs on the SS substrate as the working electrode and Li foil as the counter and reference electrodes. Transmission electron microscopy and scanning electron microscopy were used to analyze the structural and morphological evolution of the NWs before and after electrochemical testing. Preliminary results on the effect of increasing SSE layer thickness on the electrochemical cycling performance and microstructural evolution of Ge NWs half-cells with an SSE layer and LEs will be presented as a step towards the end goal of developing an all solid-state lithium ion battery with a semiconductor nanowire anode.

#44 Solid-Liquid Hybrid Lithium Ion Batteries
Isaiah Oladeji, Guangyu Chai, Bin Tran, Craig Nelson, Don Sun and Paul Valesco, Planar Energy

Lithium ion battery technology is the most promising candidate for future electrical vehicle technology. But traditional batteries are limited by their polymer separator, organic additives, and liquid electrolytes. These components determine the performance, lifetime, and safety of the battery. The replacement or elimination of these components, and the reduction of battery cost, will make electric vehicle technology a reality. Planar Energy hybrid cells are a step closer to that goal. The cells consist of all-inorganic electrodes, inorganic solid-state electrolyte film, and very low liquid electrolyte content for high rate performance. The complete cells are grown by Planar Energy using its unique, low cost ambient deposition technology.

#45 Theoretical And Experimental Studies Of Fullerite Modified By Oxidation, Intercalation, And Radiation
Charles Weatherford, Kalayu Belay and Gennady Gutsev

Since the discovery of C60 fullerene in 1985, a large amount of experimental and theoretical effort has been devoted to the study of various gas-phase and solid fullerenes, charged fullerenes, and interactions of fullerenes with organic and inorganic species. One of the prospective applications of fullerite is its use in hydrogen storage. Fullerites intercalated by different species are interesting from a technological point of view since they can be used for gas storage with a controlled yield of the gas stored. Recent experimental studies have shown that fullerite can be hydrogenated for up to 8.2 wt.% H. The pressure P = 12 MPa and temperature T = 425 to 455 °C were found to be the optimal conditions for fullerite C60 hydrogenation. Molecular hydrogen has a poor physical sorption in pure fullerite while defects such as C60O and/or intercalates drastically increase the sorption ability.

We have performed joint experimental and theoretical studies of fullerite intercalated with oxygen [1] and acetylene [2] and studied the dimerization of defect fullerenes [3] that can be formed by oxidation or irradiation. We found that oxidation of C60 fullerite intercalated by oxygen presents a rather complicated process that starts at 193°C and continues at substantially higher temperatures. It was rather surprising to find stable endohedral complexes O2@ C60-x formed by defect fullerenes. Such defect structures are capable of holding H2 also. Certain defect fullerenes can dimerize forming dumbbells. However the capacity of such dumbbells for hydrogen sorption, has not yet been studied. We also found that acetylene intercalate possesses an fcc lattice and acetylene releases under the sample heating. In addition, we have performed some preliminary work on graphene obtained from graphite oxide.

#81 Bipolar Energy Storage Technology
Julius Regalado, G4 Synergetics

The demand for efficient energy storage technology is increasing. Several emerging technologies would benefit from efficient energy and power delivery in excess of 70% round trip efficiency. Present day battery technology can be effective in many of these applications; however, several losses due to the typical construction of a battery from an array cells leads to reduced efficiency. Losses due to interconnects, packing fraction, and controls can and are significant in large format batteries (cell count >5). Therefore, a construction that minimizes energy losses would be highly desirable. All losses incurred adversely effects the performance metrics of a battery especially at high cell counts. A typical reduction in energy density and power output can be reduced by as much as 50 % (15-25 wh/kg for typical hybrid-NiMH battery back). Accordingly, G4’s approach is motivated towards eliminating energy losses due to packaging multiple cells into more efficient modules.

G4 ‘s approach applies the advantages of bipolar battery construction to minimize energy losses. Bipolar battery technology eliminates several components resulting in a package that is both energy dense, power rich and therefore highly efficient and highly effective. The result from a successful bipolar construction would result in battery with large cell count to approach the single-cell performance metrics (Whr/kg, W/kg). To verify the construction, several well-known electrochemical couples were selected for integration. The electrochemical couples were as follows: NiMH, Zn-MnO2, Li-Ion and Ultracapacitors.

NiMH was selected because it’s well understood, safe and known for its service in many applications. Zn-MnO2 was selected due to its low cost and environmentally benign attributes; Lithium-ion was selected for its energy and power richness, and Ultarcapacitor for its copious power densities in excess of 2000W/kg. G4’s is integrating each of these electrochemical couples into the bipolar format.

G4 has established bipolar battery technology as an effective energy storage design format. Multiple modules have been constructed in arrays of 5, 20 and 50 cells. The resistive loss incurred between cellular interconnect was found to be less than 5 u-ohm with insignificant mass contribution. In a conventional pack designs the interconnects can contribute significantly to battery resistance fractions and/or to mass fractions.

The Bipolar battery architecture offers many significant advantages over conventional battery technologies. Now that the essential mechanics and design factors are better understood and prototypes have been validated, G4’s focus is on incorporating advanced energy rich chemistries developed by: ANL, OVONIC and BASF into its battery technology to serve as the premier platform technology for future electrochemical and electrostatic energy storage devices to come. G4 intends to refine, produce and commercialize these technologies in Alachua, Florida.

#103 Design, Fabrication and Evaluation of Micro-Supercapacitors
Majid Beidaghi and Chunlei Wang, FIU

Supercapacitors, also called Electrochemical Capacitors (ECs), have higher power density and cycle lifetime compared to batteries and higher energy density compared to conventional electrolytic capacitors. Supercapacitors are used to power hybrid electric vehicles and portable electronic equipments and other devices. Miniaturized supercapacitors or micro-supercapacitors have attracted attention to provide power to small electronic devices. Recently our group has focused on development of on-chip micro-supercapacitors. We have explored various techniques, materials and structural designs for micro-supercapacitors. Both two and three dimensional micro-electrodes where fabricated. Various electroactive materials where integrated on the microelectrodes. These include carbon nanotubes (CNTs), Polypyrrole and manganese oxide. More recently we have also examined the integration of Graphene sheets into micro-electrodes as promising high power and energy electroactive material. Details of fabrication method and electrochemical performance of micro-supercapacitors will be presented at the meeting.

#109 Remarkable Oxygen Reduction Activity from Pure Single Wall Carbon Nanotube Films
Rajib Das and Andrew Rinzler, UF

Thin films of pure single wall carbon nanotubes deposited on hydrophobic membranes are demonstrated to have a remarkably high oxygen reduction activity. For measurements in aqueous electrolyte the activity is shown to exceed (on a mass basis) that of finely divided platinum on carbon black (Vulcan XC-72). Three terminal measurements in a specially constructed air breathing electrochemical cell demonstrate that the activity is high in base and remains high in pH neutral water. When operated as the oxygen breathing electrode in a magnesium-oxygen battery a 1.5 mm thick pure SWNT film exhibits performance that compares favorably to a highly engineered commercial Pt based electrode.

Solar Energy

#17 Determination of the Historical Solar Resource for any Latitude – Longitude location in Florida
Charles Cromer, UCF-FSEC

Engineering a solar system requires a prediction of the expected power generated from that system over time to predict cost effectiveness or for sizing to meet a particular load. This requires historical information on the solar resource available at that particular site location. The direct beam and direct global solar resource values for any geographical location in Florida were found by using actual data taken at the Florida Solar Energy Center (FSEC) for 2010 and correlating those values against clearness values derived from NOAA geostationary satellite data. Using the correlations developed, eleven years of satellite data (2000 – 2010) were used to provide expected monthly average solar resource values for any location in Florida. These solar resource values (watts per meter square per day) were developed into a web based algorithm that allows one to find the expected average solar resource for a given location in Florida. A solar Atlas for Florida was produced that provides monthly calculated values matched to colors with the lowest values of the full range of average values representing the deepest blue-purple color and the highest values of the range representing the brightest red. Twenty-six color plates were produced including direct global and direct beam annual averages as well as the direct global and direct beam monthly averages. Go to http://livewire.fsec.ucf.edu/src/ to access the solar resource calculator.

#86 Efficient Inverted Polymer Solar Cells Using Silole-Containing Low-Bandgap Polymer
Cephas Small, Jegadesan Subbiah, Frederick Steffy, Chad Amb, John Reynolds and Franky So, UF

Polymer solar cells (PSCs) are a promising alternative as low-cost renewable energy sources. In bulk-heterojunction (BHJ) photovoltaic devices the vertical phase morphology and grain size of the active layer play a crucial role in determining the exciton dissociation efficiency and charge extraction efficiency, as well as the power conversion efficiency. In an ideal device structure, the donor and acceptor molecules should segregate toward the anode and cathode, respectively. However, several donor polymer-PCBM systems have exhibited vertical phase separations that could only be optimized if the device structure was inverted such that the cathode is at the bottom and the anode is on the top of the device. In this work, we have studied the performance of normal and inverted bulk-heterojunction (BHJ) solar cells with an active layer composed of a blend of poly[(4E,4²-bis(2-ethylhexyl)dithieno[3,2-b:2²,3²-d]silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl] (DTS-BTD) and {6,6}-phenyl-C71 butyric acid methyl ester (PC71BM). To enhance the device performance of the inverted cell, a MoO3 thin film was used as an anode interlayer. For inverted cells, ZnO was used as an interlayer for the bottom cathode. The inverted devices exhibited an increase in short circuit current density (Jsc) by 32% over the conventional solar cells (16.77 mA/cm2 in the inverted devices compared to 12.71 mA/cm2 in the conventional devices). Overall, the inverted structure had a higher power conversion efficiency of 5.81% compared to the conventional structure of 4.91%. Our X-ray photoelectron spectroscopy results show that the top surface of the polymer blend is donor-rich, resulting in morphology more favorable to the inverted structure and a significantly higher short-circuit current in the inverted cells.

#18 Thin-Film Pilot Line Process Development
Don Morel, Chris Ferekides and Elias Stefanakos, USF

Thin film solar cell technology is rapidly expanding into commercialization and is expected to be the dominant technology in the future. CdTe and CuInGaSe2( CIGS) are the leading thin film technologies in terms of demonstrated performance. CdTe has already garnered significant market share due to its low production cost. Several organizations throughout the world have announced installation of large scale CIGS manufacturing lines. The success of these operations depends critically upon the refinement and optimization of the manufacturing processes. To assist in these ongoing developments we are developing a thin film pilot line facility at USF. The initial focus is on CIGS technology. The key tool in the facility is a roll-to-roll vacuum coating machine. The web width is 14, and the web can be either stainless steel or high temperature tolerant, flexible and light-weight plastics such as polyimides. The tool has a throughput capacity in the Megawatt/year range which validates its use as a prototype for manufacturing scale-up.

The key to successful manufacturing of these devices is to choose the reaction pathway that allows for optimization of the tradeoffs among efficiency, yield, materials utilization and throughput. We have been addressing each of these in several ways to guide the design and building of the deposition system. Over the past year we have focused particularly on materials utilization. Because thickness and compositional uniformity are key factors in performance and yield, deposition tools must be designed to meet these stringent demands. We have developed and are using process simulation tools to help in the design and configuration of these deposition tools. Minimizing edge losses while achieving uniformity is an important factor for all materials and is a key design consideration for the deposition tools.

Loss of In and Ga because of low sticking coefficients during deposition is also a significant materials utilization issue. In this case the process recipe is the key leveraging factor. The Group III elements are lost from the growth surface due to formation of volatile Se compounds. We have developed processing procedures which achieve significantly less loss than the conventional co-deposition process that is currently in use by most manufacturers. These insights are also guiding the design and configuration of the deposition tools that are being incorporated in the roll-to-roll machine.
While procedures are being developed to reduce the loss of Group III elements, the uncertain future cost of Indium at high production levels may still be a significant impediment to cost reductions. To address this issue we are developing kesterite solar cells. The kesterites are similar in composition and structure to CIGS but replace In and/or Ga with more earth abundant Zn and Sn. As Group II and Group IV elements respectively, Zn and Sn form a valence couple to replace the Group III element. These compounds introduce additional complexities but show promise of achieving the same performance as CIGS. The pilot deposition machine will be fully capable of incorporating their use should they meet the requisite performance objectives.

#55 Monitoring the Device Quality of CIGS Thin-Film Solar Cells
Neelkanth Dhere, Ashwani Kaul and Eric Schneller, UCF-FSEC

The process of fabricating a thin-film CIGS solar cell involves a sequence of various material deposition and post treatment processes. The completed device has a multilayer structure in which small fluctuations in the chemical composition or thickness of any one layer will compromise the overall performance of the solar cell. Therefore, it is essential to perform quality control among each successive step to ensure consistency from one run to the next. A set of analysis procedures have developed that can be performed after each step to validate that the deposition has been carried out correctly. Starting with the sputter deposition of a Molybdenum back contact, a sheet resistance measurement can confirm that this layer has sufficient thickness and conductivity. After the deposition of a Copper-Indium-Gallium precursor layer it is important to perform an elemental analysis using techniques such as energy-dispersive X-ray spectroscopy (EDS) and/or Electron Probe Micro Analysis (EPMA) to ensure that the starting precursor has the correct chemical composition. There can be fluctuations in the deposition rates of a metallic sputtering target over its lifetime, so it is necessary to constantly monitor this to avoid any inaccuracy in the elemental ratios. During the Selenization or Sulfurization process, the absorber layer is completed and the CIGS phase can be verified using both EPMA and X-ray diffraction. Since this is the most important ingredient, additional characterization tools would be beneficial. The heterojunction partner layer, Cadmium Sulfide, is prepared by a chemical bath deposition. This layer must be of adequate thickness to provide a uniform junction across the entire cell area, but not be too thick to block a significant part of incident photons from reaching the absorber. The thickness can be estimated by the color of the film (interference pattern) after deposition over the absorber. However, a more exact measurement can be obtained by verifying the transmission spectrum from a bare glass sample that went through the same treatment process. The chemical bath deposition is extremely sensitive to small fluctuations in time and temperature, and bath compositions so it is important to verify that this layer has been deposited successfully. The final deposition of the ZnO/ZnO:Al TCO bilayer must also be verified to provide a consistent high quality device, as problems with this layer can lead to shunt paths within the device and high series resistance. Measurements of the sheet resistance and transmission spectrum can ensure a film of required properties. Measurements can be done on a bare witness glass sample that went through the same deposition process. It is very important to monitor each step carefully during the fabrication process of a CIGS thin-film solar cell. Small changes or variations in any one layer will compromise the entire device and cause large changes in the cell parameters. Analyzing a sample after each step can ensure consistency in device quality.

#8 High Efficiency Organic Photovoltaic Cell and Novel Polymer and Device Structure
Cephas E. Small, Song Chen, Sai-Wing Tsang, Jegadesan Subbiah, Chad Amb, Tzung-Han Lai, John R. Reynolds and Franky So, UF

Single layer bulk heterojunction organic photovoltaic (OPV) cell based on low band gap polymers and fullerene derivatives theoretically can reach 10% power conversion efficiency (PCE). Tremendous progress has been gained in OPV technology in the past decade. Numerous low band-gap polymers have been developed in order to utilize the electronic properties and optical absorption in a composite layer with the fullerene derivatives. Significant improvements in charge collection efficiency and device stability have also been shown with novel device structures. In this presentation, we will present our recently developed OPV cells with over 8% PCE under one sun irradiation. The devices also demonstrate remarkable improvement in stability compared to previously reported OPV cells. Such high device efficiency and stability are attributed to the high optical absorption of the dithienogermole-thienopyrrolodione (DTG-TPD) low band-gap polymer and the use of nanocrystal modified charge collecting electrode. Details of the opto-electronic properties of the materials and devices will be presented. The solution processable DTG-TPD polymer and nanocrystals are believed to have great potential for commercialization using the low-cost roll-to-roll printing process.

#111 Photovoltaic Effect Based on Mott Insulators
Efstratios Manousakis, FSU

We have shown that a narrow-gap Mott insulator, when appropriately chosen, can become the basis for solar cells of high efficiency. These materials are, by their nature, characterized by strong local Coulomb repulsion between the outer-shell electrons which leads to an enhancement of the impact ionization rate. Namely, the strong electron-electron interaction causes the highly energetic photo-excited electron/hole pair to decay into multi electron/hole pairs, in a time-scale shorter than any other relaxation processes. We also show that the ideal maximum efficiency in these types of materials can be significantly higher than the Queisser-Shockley limit for maximum efficiency in the absence of impact ionization. We will also discuss cases of transition metal oxide based materials which we are currently studying using ab initio methods for electronic structure calculations.

ORAL PRESENTATIONS SESSION IV

Energy Efficiency

#80 Application of Ground Source Heating and Cooling System at the Syracuse CoE Headquarters Building
Suresh Santanam, Syracuse Center for Excellence

Use of natural heating and cooling strategies was one of the key design objectives in the design and development of the new Syracuse Center of Excellence in Energy and Environmental Systems (Syracuse CoE) headquarters building. Application of ground source heating and cooling (GSHC) loop in the design was an element unique to this building which is located within the urban center of Syracuse, New York. An effective GSHC loop was designed using software simulations in conjunction with on-site test bore geothermal data. The GSHC loop consists of 49 wells, each 300 feet deep. The well filed is a rectilinear grid, with wells spacing at 20-ft. The entire well field and all horizontal pipe runs and interconnects are buried below grade, such that the space available for an on-site surface parking lot. The GSHC loop system was constructed and successfully tested and deployed. The GSHC loop works in concert with the building’s hot water and boiler water thermal loops to maintain the required thermal conditioning for the building spaces during the heating season. During summer months, the GSHC loop is used to reject heat from the building. In this manner, the building uses the ground as a natural reservoir to augment and manage heating and cooling requirements of the building. GSHC loop at the Syracuse CoE building become operational at the end of 2009. The GSHC loop heat input and extraction is being carefully monitored through the building management system (BMS) to prevent any significant increase or decrease in undisturbed ground temperature. The BMS also collects information on the heat delivery by the GSHC loop (GWL), the hot water loop (HWL), and the boiler water loop (BWL). Operational data from the building management system was extracted and analyzed to assess and characterize the performance of the GSHC loop during winter months of 2009-2010. Initial results show that the GSHC is performing as designed, contributing up to 1.0 million BTU per of hour of heat to the building systems. Our preliminary assessment during the first winter of operation shows that the GSHC loop could deliver approximately 20 percent of the heating needs of the building. We are continuing our data collection and analysis. We anticipate that more extensive data over multiple seasons will be required to fully document the efficacy of the GSHC loop at this building. We envision that our experience and information related to construction of this GSHC loop system provides additional data to enable other proposed urban building developers to explore the use of such a system in their construction.

#94 KUNNE Indoor Climate Control Temperature & Humidity Management Technology
Teppo Jokinen, Palm Beach R&D

KUNNE Air Conditioning Systems:

1. Eliminate air filters

2. Eliminate the Consistent Need for Duct Cleaning and Disinfections

3. Eliminate the Need for Special Equipment Typically Used in Conventional A/C Systems

4. Patented and Award-Winning Product (R&D Magazine 100 Award)

5. Eliminate “SICK Houses”

6. Far exceeds the Equipment Life Expectancy of Conventional A/C Equipment

7. Overall Savings in Costs (Never – Before used Technologies)

8. Improved health of indoor environments

#64 Efficiency – Maximize Full Potential, Sustain Savings, Mitigate Risk
Michelle Simon, Schneider Electric

Learning how to strategically address energy efficiency and facility resources is of upmost importance, even in good economic times. With challenging budgets and an increased need to improve efficiency and implement needed capital improvements, many factors need to be considered, both long-term and short.

The goal of this presentation will be to help the audience navigate the enormity of energy information available, gain knowledge on successful processes, and overcome some of the initial challenges surrounding the implementation and sustainability of energy efficiency initiatives.

This will allow organizations to strategically align their resources and evaluate opportunities based on performance-driven and cost mitigation results. Even now more than ever, reduction in operating costs and utilizing non-traditional means of procurement through alternative public-finance options is paramount to institutional success. In order to be successful, the decision makers of the organization must have the tools needed to bring that success to fruition.

#90 The Role of Energy Storage in the Adoption of Renewable Energy for the Grid
Joseph Simmons, FGCU

Two major sources of renewable energy for electricity production (solar and wind) suffer from unpredictable intermittency and a mismatch of production vs load. Energy storage can be used to fill in the intermittency gaps, shift electrical production from periods of low demand to periods of high demand, and defer transmission upgrades. This presentation discusses energy storage by supercapacitors, batteries and compressed air and gives examples of tests under way and in the planning stage of a research partnership between the Renewable Energy Program at Florida Gulf Coast University and the Arizona Research Institute for Solar Energy at the University of Arizona. Tests include the use of novel high energy-density supercapacitors for the smoothing of electricity production from high efficiency, single-axis tracking solar modules in Florida and Arizona, and peak-shaving of PV solar production to cover the afternoon and evening load using a novel quasi-adiabatic compressed air energy storage system.

#117 Geothermal, Basements & Stormwater Vaults To Reduce Energy & Conserve Water In Florida
Thomas Mudano and Steve Hickok, Sustainable Environment Research Foundation

The Sustainable Environment Research Foundation (SERF) is a catalyst to bring together businesses, non-profit organizations, research and educational institutions into a collaborative environment to research and develop emerging alternative energy technologies, water conservation, sustainable building construction methods, marine sciences and environment.

Known as the “Sunshine State,” it should come as no surprise that Florida ranks 3rd in the nation for energy consumption due to the abundant use of air conditioning. Geothermal energy is an untapped resource for “cooling” buildings in Florida. The goal is to capitalize on geothermal technology in Florida to reduce energy costs. Geothermal components of the SERF facility incorporate Geothermal Air Conditioning Systems & Heat Recovery: The facility shall have types of geothermal systems in place used to reduce energy costs. Water is the best conduit to remove heat from a building. With a geothermal system, heat that has been removed to help cool the building can be reused to provide hot water for the water heating system. The result further reduces energy needs of the facility and maximizes efficiencies.

Another focus of SERF relates to water conservation, storage and reuse. With new technology, large-sized rainwater harvesting & storm water cisterns can be constructed below the ground or buildings, increasing the amount of storm water captured, cleaned and “re-used” within a building. Research of the system will take place on an on-going basis to continuously improve upon the technologies used.

Until now, constructing basements in Florida and in areas where there is a high water table has prevented building below the ground. Using new technology, a water-tight basement system can be constructed to reduce energy costs by taking advantage of the normal ground-cooled temperatures of 72° – 74° and increasing usable space for data centers, shelters, or other residential or commercial uses. Using an innovative system, and utilizing the existing soil to create concrete walls in place without excavation. The ‘cutter-soil-mixing’ (CSM) technology is truly “green” and creates a water tight basement or storm water vault anywhere in Florida.

Energy Policy

#76 Cleantech Manufacturing: Made in Florida
Carlos M Gonzalez, US BlueChip Energy & Advanced Solar Photonics

BlueChip Energy, LLC (BCE) is a fully integrated solar PV power generator, occupying all segments of the solar power value chain — from the manufacturing of solar panels and balance of systems components by its wholly owned subsidiary Advanced Solar Photonics, to the sale of turnkey solar power plants, to the sale of solar electricity to utility, commercial and residential customers. BCE develops, finances, builds, operates, and monitors solar plants for companies and individuals, as well as for its own portfolio.

BlueChip Energy’s two flagship utility scale solar projects, theRinehart Solar Farm (10 MW) and the Sorrento Solar Farm (40 MW), received approval from the Federal Energy Regulatory Commission (FERC) as self-certified small power production facilities, or Qualified Facilities (QFs) earlier this year, requiring the local utility to provide interconnection to them and purchase the electricity they produce. Additionally, these two solar farms have received approval to operate as Exempt Wholesale Generators (EWGs), providing the facilities with undisputed access to the power distribution network. FERC has also granted the company Market-Based Rate Authorization, allowing BCE to purchase and sell wholesale electricity and offer renewable energy products to customers.

#11 Energy Consumption Simulation and Construction Cost Analysis for Wood and Steel Framing System in Florida Residential Housing – Case Study
Aiyin Jiang, UNF

Comparing to wood stud framing, steel stud framing offers some advantages for its fundamental characteristics. However, it is not clear how steel stud framing compares with wood stud framing in terms of overall cost to the builders and energy performance to the residents. The study conducts construction cost analysis and simulates energy performance for these two different wall framing system for houses in four metropolitan cities which are located in four different weather areas in Florida. It indicates that a house built with steel wall frame is 53% more in construction cost and 6%-7% more in annual energy consumption than wood wall frame. Further research would be conducted in studying the impact on energy performance and construction cost by modifying steel stud spacing, novel insulation materials, and new construction techniques.

#34 An Upstream Carbon Pricing Modeling Approach to Establish a Public Benefit Fund for Florida
Zafar Siddiqui, Ted Kury and Julie Harrington, FSU & UF

This paper presents an economic modeling approach for upstream carbon pricing with the dual purpose of generating a public benefit fund (PBF) for Florida while addressing greenhouse gas emissions. The PBF can be used towards clean technology investment in addition to support those contributing fossil fuel emitters to assist in a transition towards cleantech sources of energy generation.

The definition of upstream carbon pricing involves several nodes ranging from fossil fuel extraction through drilling/mining, or importation into an economy, to various distribution mechanisms. For the purpose of this paper, the producers, where fuels first enter the economy, are taken as upstream in the fuel chain. The advantage is that an upstream system captures virtually all fossil fuel use and carbon emissions while controlling for leakages, at minimum cost. The economic model was developed to be available and user friendly for researchers, policymakers, and other interested parties. It works bidirectional, based on varying input data and dependent on user’s preferable variable and unit regarding model outcome(s).
The model can either take the amount of the PBF as given, and calculate the necessary carbon price, retail electricity charge, or sales tax addition, or calculate the amount of PBF generated by a given carbon price, retail electricity charge, or sales tax addition. A least cost economic dispatch model is used to approximate electric utilities fuel price elasticities. The hourly cost is calculated for each available generating unit. For units with the capability to burn different fuels, the cost and emissions rate of each fuel are considered and the least-cost alternative is selected. Then all of the generating units are ordered from lowest cost to highest, and the units with the lowest hourly costs are dispatched until the hourly electric loads are met. During execution, the model tracks the energy production for each unit, as well as the units of fuel burned, the total dispatch costs, and the carbon emissions. These output variables can be aggregated by utility, type of plant and fuel type, among others.

Using this modeling approach, different scenarios were examined with carbon prices ranging from $0.40 to $21 per metric ton, electricity prices ranging from $0.125/kWh to $0.148/kWh and corresponding PBF results ranging from $100 Million to $5.2 Billion. Imposition of a price of $5 per metric ton of carbon emitted in 2012 would yield $ 1.29 Billion in PBF and reduces the emission by 2.31 Million Metric Tons over BAU level . Other corresponding policy options would be an electricity price of 12 cents/kWh or 0.4% addition in sales tax in Florida. The model provides an initial foray into modeling varied energy pricing options in order to develop a state-specific PBF as a means to provide investment opportunities for current generating units and for cleantech businesses.

#75 Carbon Revenue Redistribution Strategies via Subsidies for Low-Emission Generators
Patricio Rocha and Tapas Das, USF

The implementation of a CO₂ emissions control scheme, either a cap-and-trade program with auctioned permits or a carbon tax, will provide the government with an important new source of revenue. Several economists advocate for the redistribution of this carbon revenue i.e., for the emissions control schemes to be revenue neutral. In this paper, we present an optimization model to obtain redistribution strategies of the carbon revenue collected by an electricity-sector emissions control scheme. The redistribution is accomplished via allocation of subsidies for low-emission generators. The allocation is obtained by maximizing a social welfare function. We consider two types of subsidies: bid subsidies, which are aimed at reducing the bid price of low-emission generators during an electricity auction; and R & D subsidies, which are aimed at increasing the R & D investments of low-emission generators and long run reduction of their bid prices. For each type of subsidy, we present a model and demonstrate its application via an example problem. We examine the impact of transmission capacity and the amount of revenue available for redistribution on subsidy allocation policies and the resulting benefits of load price reduction, market share increase of low-emission generators, and CO₂ emissions reduction in the network.

#98 Characterizing Energy Efficiency Using Utility and Appraiser Data
Nicholas Taylor, UF

The residential building sector accounts for a significant portion of US energy consumption (EIA 2009) and associated greenhouse gas emissions. The sector also offers substantial opportunities for efficiency gains and overall energy savings (Dietz 2010; Horowitz 2007). Over the last 15 years, federal, state and utility residential energy efficiency programs have continued to develop and expand. While some are prescriptive, the most highly regarded are based on HERS scores. While it is understood that the fundamentals of the HERS process, and programs that rely on it, are based on sound building science principles, few studies have evaluated how program implementation, regional impacts and occupant behavior affect actual homes’ absolute and relative energy consumption (i.e., performance) and the expendable income via reduced utility bills on which energy efficiency mortgages are predicated. This paper examines the energy performance of homes participating in various energy efficiency programs for new residential construction with the objective of assessing whether HERS-rated performance is a reliable indicator of post-occupancy energy performance.