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Distributed Generation

Brayton Energy

1kW Recuperated Brayton-Cycle Engine Using Positive-Displacement Components

Brayton Energy will develop a 1 kW recuperated Brayton cycle engine to produce heat and electricity for residential use. To begin the cycle, compressed air is preheated in a recuperator before adding fuel, then the air-fuel mix is ignited in a combustion chamber. The high temperature exhaust gases then expand through the turbine, providing some of the work that drives the compressor and also produces electricity in a generator. Major project innovations include the use of a rotary screw-type compressor and expander that operate in a sub-atmospheric Brayton cycle i.e. below atmospheric pressure. In addition, Brayton will also use their innovative patented recuperator that is currently in production, and an ultra-low emission combustor.

Brown University

Marine Hydrokinetic Energy Harvesting Using Cyber-Physical Systems

Brown University is developing a power conversion device to maximize power production and reduce costs to capture energy from flowing water in rivers and tidal basins. Conventional methods to harness energy from these water resources face a number of challenges, including the costs associated with developing customized turbine technology to a specific site. Additionally, sites with sufficient energy exist near coastal habitats which depend on the natural water flow to transport nutrients. Brown University's tidal power conversion devices can continuously customize themselves by using an onboard computer and control software to respond to real-time measurements, which will increase tidal power conversion efficiency. Brown University's technology will allow for inexpensive installation and software upgrades and optimized layout of tidal power generators to maximize power generation and mitigate environmental impacts.

California Institute of Technology

Optics for Full Spectrum, Ultrahigh Efficiency Solar Energy Conversion

The California Institute of Technology (Caltech) is developing a solar module that splits sunlight into individual color bands to improve the efficiency of solar electricity generation. For PV to maintain momentum in the marketplace, the energy conversion efficiency must increase significantly to result in reduced power generation costs. Most conventional PV modules provide 15-20% energy conversion efficiency because their materials respond efficiently to only a narrow band of color in the sun's spectrum, which represents a significant constraint on their efficiency. To increase the light conversion efficiency, Caltech will assemble a solar module that includes several cells containing several different absorbing materials, each tuned to a different color range of the sun's spectrum. Once light is separated into color bands, Caltech's tailored solar cells will match each separated color band to dramatically improve the overall efficiency of solar energy conversion. Caltech's approach to improve the efficiency of PV solar generation should enable improved cost-competitiveness for PV energy.

California Institute of Technology

Micro-Optical Tandem Luminescent Solar Concentrator

Researchers at the California Institute of Technology (Caltech) and their partners will design and fabricate a new CPV module with features that can capture both direct and diffuse sunlight. The team's approach uses a luminescent solar concentrator (LSC) sheet that includes quantum dots to capture and re-emit sunlight, micro-PV cells matched to the color of the light from the quantum dots, and a coating of advanced materials that enhance concentration and delivery of sunlight to the micro-PV cells. In addition, the light not captured by the quantum dots will impinge on a tandem solar cell beneath the LSC sheet. The design of the LSC will focus on lowering the number of expensive micro-PV cells needed within the concentrator sheet, which will reduce system costs, but still maintain high efficiency. The design will also allow the module to be effective without any tracking system, making it potentially attractive for all PV markets, including space-constrained rooftops.

Carnegie Mellon University

Nanocomposite Magnet Technology for High Frequency MW-Scale Power Converters

Carnegie Mellon University (CMU) is developing a new nanoscale magnetic material that will reduce the size, weight, and cost of utility-scale PV solar power conversion systems that connect directly to the grid. Power converters are required to turn the energy that solar power systems create into useable energy for the grid. The power conversion systems made with CMU's nanoscale magnetic material have the potential to be 150 times lighter and significantly smaller than conventional power conversion systems that produce similar amounts of power.

Cogenra Solar, Inc.

Double-Focus Hybrid Solar Energy System with Full Spectrum Utilization

Cogenra Solar is developing a hybrid solar converter with a specialized light-filtering mirror that splits sunlight by wavelength, allowing part of the sunlight spectrum to be converted directly to electricity with photovoltaics (PV), while the rest is captured and stored as heat. By integrating a light-filtering mirror that passes the visible part of the spectrum to a PV cell, the system captures and converts as much as possible of the photons into high-value electricity and concentrates the remaining light onto a thermal fluid, which can be stored and be used as needed. Cogenra's hybrid solar energy system also captures waste heat from the solar cells, providing an additional source of low-temperature heat. This hybrid converter could make more efficient use of the full solar spectrum and can provide inexpensive solar power on demand.

Colorado School of Mines

Low-Cost Intermediate-Temperature Fuel Flexible Protonic Ceramic Fuel Cell Stack

The Colorado School of Mines is developing a mixed proton and oxygen ion conducting electrolyte that will allow a fuel cell to operate at temperatures less than 500°C. By using a proton and oxygen ion electrolyte, the fuel cell stack is able to reduce coking - which clogs anodes with carbon deposits - and enhance the process of turning hydrocarbon fuels into hydrogen. Today's ceramic fuel cells are based on oxygen-ion conducting electrolytes and operate at high temperatures. Mines' advanced mixed proton and oxygen-ion conducting fuel cells will operate on lower temperatures, and have the capacity to run on hydrogen, ethanol, methanol, or methane, representing a drastic improvement over using only oxygen-ion conducting electrolytes. Additionally, the fuel cell will leverage a recently developed ceramic processing technique that decreases fuel cell manufacturing cost and complexity. Additionally, their technology will reduce the number of manufacturing steps from 15 to 3, drastically reducing the cost of distributed generation applications.

Colorado School of Mines

High Efficiency, Low Cost & Robust Hybrid SOFC/IC Engine Power Generator

The Colorado School of Mines will develop a hybrid power generation system that leverages a pressurized, intermediate-temperature solid oxide fuel cell (SOFC) stack and an advanced low-energy-content fuel internal combustion (IC) engine. The custom-designed, turbocharged IC engine will use the exhaust from the anode side of the SOFC as fuel and directly drive a specialized compressor-expander that supplies pressurized air to the fuel cell. High capital costs and poor durability have presented significant barriers to the widespread commercial adoption of SOFC technology. In part, these challenges have been associated with SOFC high operating temperatures of 750-1000°C (1382-1832°F). This team will use a robust, metal-supported SOFC (600°C or 1112°F) technology that will provide greater durability, better heat management, and superior sealing over standard ceramic-supported SOFC designs. The modified diesel IC engine in a hybrid system provides a low-cost, controllable solution to use the remaining chemical energy in the fuel cell exhaust. The system will use the hot air and exhaust gases it produces to keep components running at the proper temperatures to maximize overall efficiency. The team will also develop supporting equipment, including a specialized compressor-expander and power inverter. The new system has the potential to enable highly-efficient, cost-effective distributed power generation.

Columbia University

Demonstration of Near-Field Thermophotovoltaic (TPV) Energy Generation

The Columbia University team is developing a proof-of-concept solid-state solution to generate electricity from high-temperature waste heat (~900 K) using thermal radiation between a hot object placed in extreme proximity (<100 nm) to a cooler photovoltaic (PV) cell. In this geometry, thermal radiation can be engineered such that its spectrum is quasi-monochromatic and aligned with the PV cell's bandgap frequency. In this case, it is estimated that electricity can be generated with a conversion efficiency beyond 25% and with a power density that could greatly outperform currently available thermal photovoltaic devices and other thermoelectric generator designs. To overcome the significant challenge of maintaining the proper distance between a hot side emitter and a cooler PV junction to prevent device shorting, the team will develop microelectromechanical actuation systems to optimally orient the PV cell. By providing a universal solid-state solution that can, in principle, be mounted and scaled to any hot surface, this technology could help retrieve a significant fraction of heat wasted by U.S. industries

Cree Fayetteville, Inc.

Compact, High Voltage, High Energy Density Diamond Capacitors for Power Electronics Applications

Cree Fayetteville will develop high voltage (10kV), high energy density (30 J/cm3), high temperature (150 °C+) capacitors utilizing chemical vapor deposition (CVD) diamond capable of powering the next generation of high-performance power electronics systems. CVD diamond is a superior material for capacitors due to its strong electrical, mechanical, and materials qualities that are inherently stable over varying temperatures. It also has similar qualities of single crystal diamond without the high cost. Commercial CVD diamond deposition will be utilized to prove the feasibility of the technology with consistent, low cost, high-resistivity diamond films. The CVD diamond will be used as an optimal dielectric for today's demanding power electronics applications. Most power electronics systems require large capacitors to filter switching noise and provide sufficient energy to loads during transient periods. But present-day film and ceramic capacitor technologies are quickly becoming obsolete as the switching frequency and operating temperature of power electronic systems continue to increase. Using CVD diamond for this purpose may provide a capacitor technology that does not experience lifetime-limiting overheating, at both low frequency (high energy) and high frequency (low equivalent series resistance) conditions, and with reasonable size and cost. In conjunction with a robust electrode metallurgy and proven high-temperature packaging techniques, energy densities in excess of 80 J/cm3 have been modeled; the proposed specification of 30 J/cm3 will be a drastic improvement over current technologies. The team's effort will primarily focus on the development and characterization of multi-layer CVD diamond capacitor design, packaging, and fabrication techniques, resulting in proof of concept prototypes to demonstrate the technology feasibility.

Cree, Inc.

Agile Direct Grid Connect Medium Voltage 4.7-13.8 kV Power Converter for PV Applications Utilizing Wide Band Gap Devices

Cree is developing a compact, lightweight power conversion device that is capable of taking utility-scale solar power and outputting it directly into the electric utility grid at distribution voltage levels--eliminating the need for large transformers. Transformers "step up" the voltage of the power that is generated by a solar power system so it can be efficiently transported through transmission lines and eventually "stepped down" to usable voltages before it enters homes and businesses. Power companies step up the voltage because less electricity is lost along transmission lines when the voltage is high and current is low. Cree's new power conversion devices will eliminate these heavy transformers and connect a utility-scale solar power system directly to the grid. Cree's modular devices are designed to ensure reliability--if one device fails it can be bypassed and the system can continue to run.

Cummins Corporate Research & Technology

Efficient Knock Suppression in Spark Ignited Engines

Cummins Corporate Research & Technology will develop an advanced high efficiency natural gas-fueled internal combustion engine for high-power distributed electricity generation. The team is seeking to achieve 55% brake thermal efficiency while maintaining low exhaust emissions. The enabling technology is wet compression, where fine droplets of water are sprayed directly into the engine cylinders, causing the charge temperature to drop and thereby prevent the onset of damaging engine knock at high compression ratios. Since it takes less energy to compress cooler air, the savings from reduced compression work can be passed on to increase the net engine output. Wet compression is a transformative technology that dramatically improves engine efficiency while still allowing for conventional engine manufacturing methods at existing facilities.

Det Norske Veritas (U.S.A)

Third Party Valuation of Grid and Microgrid Energy Storage Technologies

Det Norske Veritas (DNV GL) and Group NIRE will provide a unique combination of third-party testing facilities, testing and analysis methodologies, and expert oversight to the evaluation of ARPA-E-funded energy storage systems. The project will leverage DNV GL's deep expertise in economic analysis of energy storage technologies, and will implement economically optimized duty cycles into the testing and validation protocol. DNV GL plans to test ARPA-E storage technologies at its state-of-the-art battery testing facility in partnership with the New York Battery and Energy Storage Technology Consortium. Those batteries that pass the rigorous evaluation process will be adapted for testing under real world conditions on Group NIRE's multi-megawatt, wind-integrated microgrid in Texas. Testing will show how well the ARPA-E storage technologies can serve critical applications and will assist ARPA-E-funded battery developers in identifying any issues with performance and durability. This testing will also deliver performance data that buyers of grid storage need, enabling informed choices about commercial adoption of grid storage technologies.

FloDesign Wind Turbine Corp.

Breakthrough High-Efficiency Shrouded Wind Turbine

FloDesign's innovative wind turbine, inspired by the design of jet engines, could deliver 300% more power than existing wind turbines of the same rotor diameter by extracting more energy over a larger area. FloDesign's unique shrouded design expands the wind capture area, and the mixing vortex downstream allows more energy to flow through the rotor without stalling the turbine. The unique rotor and shrouded design also provide significant opportunity for mass production and simplified assembly, enabling mid-scale turbines (approximately 100 kW) to produce power at a cost that is comparable to larger-scale conventional turbines.

Foro Energy, Inc.

Low-Contact Drilling Technology to Enable Economical EGS Wells

Foro Energy is developing a unique capability and hardware system to transmit high power lasers over long distances via fiber optic cables. This laser power is integrated with a mechanical drilling bit to enable rapid and sustained penetration of hard rock formations too costly to drill with mechanical drilling bits alone. The laser energy that is directed at the rock basically softens the rock, allowing the mechanical bit to more easily remove it. Foro Energy's laser-assisted drill bits have the potential to be up to 10 times more economical than conventional hard-rock drilling technologies, making them an effective way to access the U.S. energy resources currently locked under hard rock formations.

FuelCell Energy, Inc.

Adaptive SOFC for Ultra High Efficiency Power Systems

FuelCell Energy will develop an adaptive, pressurized solid oxide fuel cell (SOFC) for use in hybrid power systems. Hybridized power generation systems, combining energy efficient SOFCs with a microturbine or internal combustion (IC) engine, offer a path to high efficiency distributed generation from abundant natural gas. Proof-of-concept systems have shown the potential of this hybrid approach, but component optimization is necessary to increase system efficiencies and reduce costs. Existing SOFC stacks are relatively expensive components, and improving their efficiency and robustness would enhance the overall commercial viability of these systems. This team's approach is to focus directly on improving SOFCs with hybrid integration as their end goal. Their adaptive cells will withstand the necessary pressure fluctuations, and the compact stack design aims to make the best use of heat transfer while minimizing leakage losses and maintaining high performance. The team will take a modular approach, building 2-5kW stacks that can be grouped together in a pressurized container. These modules can be added or removed as needed to suit the scale of the hybrid system, enabling a range of power applications. The baseline cell technology will also be modified through advanced materials that extend the useful life of stack and mitigate the harmful effects of contaminants on fuel cell performance. If successful, these adaptive, efficient, robust SOFCs could provide a path to greater than 70% efficiency when integrated into a hybrid system.

FuelCell Energy, Inc.

Dual-Mode Intermediate Temperature Fuel Cell: Liquid Fuels and Electricity

FuelCell Energy will develop an intermediate-temperature fuel cell that will directly convert methane to methanol and other liquid fuels using advanced metal catalysts. Existing fuel cell technologies typically convert chemical energy from hydrogen into electricity during a chemical reaction with oxygen or some other agent. FuelCell Energy's cell would create liquid fuel from natural gas. Their advanced catalysts are optimized to improve the yield and selectivity of methane-to-methanol reactions; this efficiency provides the ability to run a fuel cell on methane instead of hydrogen. In addition, FuelCell Energy will utilize a new reactive spray deposition technique that can be employed to manufacture their fuel cell in a continuous process. The combination of these advanced catalysts and advanced manufacturing techniques will reduce overall system-level costs.

Gas Technology Institute

Hybrid Solar System

Gas Technology Institute (GTI) is developing a hybrid solar converter that focuses sunlight onto solar cells with a reflective backside mirror. These solar cells convert most visible wavelengths of sunlight to electricity while reflecting the unused wavelengths to heat a stream of flowing particles. The particles are used to store the heat for use immediately or at a later time to drive a turbine and produce electricity. GTI's design integrates the parabolic trough mirrors, commonly used in CSP plants, into a dual-mirror system that captures the full solar spectrum while storing heat to dispatch electricity when the sun does not shine. Current solar cell technologies capture limited portions of the solar spectrum to generate electricity that must be used immediately. By using back-reflecting gallium arsenide (GaAs) cells, this hybrid converter is able to generate both electricity from specific solar wavelengths and capture the unused light as heat in the flowing particles. The particle-based heat storage system is a departure from standard fluid-based heat storage approaches and could enable much more efficient and higher energy density heat storage. GTI's converter could be used to provide solar electricity whether or not the sun is shining.

General Electric

Electrothermal Energy Storage with a Multiphase Transcritical CO2 Cycle

GE is designing and testing components of a turbine system driven by high-temperature, high-pressure carbon dioxide (CO2) to develop a more durable and efficient energy conversion system. Current solar energy system components break down at high temperatures, shortening the system's cycle life. GE's energy storage system stores heat from the sun in molten salt at moderate temperature and uses surplus electricity from the grid to create a phase change heat sink, which helps manage the temperature of the system. Initially, the CO2 remains at a low temperature and low pressure to enable more efficient energy storage. Then, the temperature and pressure of the CO2 is increased and expanded through a turbine to generate dispatchable electricity. The dramatic change in temperature and pressure is enabled by an innovative system design that prevents thermal losses across the turbine and increases its cycle life. This grid-scale energy storage system could be coupled to a hybrid solar converter to deliver solar electricity on demand.

General Electric

Tensioned Fabric Wind Blades

General Electric (GE) Power & Water is developing fabric-based wind turbine blades that could significantly reduce the production costs and weight of the blades. Conventional wind turbines use rigid fiberglass blades that are difficult to manufacture and transport. GE will use tensioned fabric uniquely wrapped around a spaceframe blade structure, a truss-like, lightweight rigid structure, replacing current clam shell wind blades design. The blade structure will be entirely altered, allowing for easy access and repair to the fabric while maintaining conventional wind turbine performance. This new design could reduce production costs by 70% and enable automated manufacturing while reducing the processing time by more than 50%. GE's fabric-based blades could be manufactured in sections and assembled on-site, enabling the construction of much larger wind turbines that can capture more wind with significantly lower production and transportation costs.

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