Distributed Generation
MicroLink Devices
Epitaxial Lift-Off III-V Solar Cell for High Temperature Operation
MicroLink Devices is developing a high-efficiency solar cell that can maintain efficient operation at high temperatures and leverage reusable cell templates to reduce overall cell cost. MicroLink's cell will be able to operate at temperatures above 400°C, unlike today's solar cells, which lose efficiency rapidly above 100°C and are likely to fail at high temperatures over time. MicroLink's specialized dual-junction design will allow the cell to extract significantly more energy from the sun at high temperature than today's cells, enabling the next generation of hybrid solar converters to deliver much higher quantities of electricity and useful dispatchable heat. When integrated into hybrid solar converters, heat rejected from the cells at high temperature can be stored and used to generate electricity when the sun is not shining.
MicroLink Devices
High-Efficiency, Lattice-Matched Solar Cells Using Epitaxial Lift-Off
MicroLink Devices is developing low-cost, high-efficiency solar cells to capture concentrated sunlight in an effort to increase the amount of electricity generated by concentrating solar power plants. The continued growth of the CPV market depends strongly on continuing to reduce the cost of CPV solar cell technologies. MicroLink will make an all-lattice-matched solar cell that can achieve greater power conversion efficiency than conventional CPV technologies, thereby reducing the cost of generating electricity. In addition, MicroLink will use manufacturing techniques that allow for the reuse of expensive solar cell manufacturing templates to minimize costs. MicroLink's innovative high-efficiency solar cell design has the potential to reduce PV electricity costs well below the cost of electricity from conventional non-concentrating PV modules.
Mohawk Innovative Technology, Inc.
High-Speed Microturbine with Air Foil Bearings for Residential CHP
Mohawk Innovative Technology, Inc. (MiTi) and its partners at the University of Texas at Austin and Mitis SA will develop a 1 kW microturbine generator for residential CHP based on MiTi's hyperlaminar flow engine (HFE) design. Key innovations of the design include highly miniaturized components operating at ultra-high speeds and a viscous shear mechanism to compress air that is mixed with natural gas and undergoes a flameless combustion process that minimizes emissions. The hot combustion gas drives the turbine and generator to produce electricity and heat water for household use. Besides using the viscous shear-driven compressor and turbine impellers and flameless combustion, the turbogenerator uses permanent magnet generator elements and air foil bearings with very low power loss, all of which are combined into a highly efficient, low emission, and oil-free turbomachine for residential combined heat and power that requires little or no maintenance.
NanoConversion Technologies, Inc.
High-Efficiency Thermoelectric CHP
NanoConversion Technologies, along with researchers from Gas Technologies Institute (GTI), will develop a high-efficiency thermoelectric CHP system. This is a solid-state device that uses heat to create electricity and contains no moving parts, thus creating no noise or vibrations. Instead, this thermoelectric CHP engine uses a novel concentration mode-thermoelectric converter (C-TEC) to harness the heat of the natural gas combustor to vaporize and ionize sodium, creating positive sodium ions and electrons that carry electric current. The C-TEC uses this sodium expansion cycle to produce electricity using an array of electrochemical cells. The superadiabatic combustor technology from GTI provides a low emission external combustion heat source with 95% fuel-to-heat efficiency and a stable temperature compatible with the C-TEC units.
National Renewable Energy Laboratory
Ultrahigh Efficiency Photovoltaics at Ultralow Costs
This project team, led by the National Renewable Energy Laboratory (NREL), will employ hydride vapor phase epitaxy (HVPE), a fast growth technique used to produce semiconductors, to lower the manufacturing cost of multijunction solar cells. Additionally the team will develop new materials to be used in the HVPE process, enabling a chemical liftoff method that allows reuse of substrates. The chemical liftoff will mitigate costs of substrates, further reducing the overall system cost. NREL's approach will leverage this improved HVPE technology to produce thin, flexible, highly efficient multijunction cells, with very high power at low cost. III-V PV has several inherent advantages over other PV materials, including higher efficiency, low temperature coefficients, and low material usage. The novel combination of HVPE growth of multijunction solar cells and substrate reuse could result in more cost-effective, higher performing multijunction solar cells, which could ultimately lower the cost and increase the efficiency of PV systems. These innovations could spur greater adoption of PV systems and reduce reliance on fossil-fuel power generation.
NexTech Materials, Ltd. dba Nexceris, LLC
Advanced Solid Oxide Fuel Cell Stack for Hybrid Power Systems
Nexceris will develop a compact, ultra-high efficiency solid oxide fuel cell (SOFC) stack tailored for 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 and improving their efficiency and robustness would enhance the overall commercial viability of these systems. Nexceris' SOFC stack design includes a patented high performance planar cell design and a novel anode current collector that that provides structural support to each cell during pressurized operation, helps define the flow of fuel gas through the stack, and improves control over the reaction of natural gas in the cell, and a sealing approach that facilitates pressurized stack operation. If successful, this stack design will result in increased performance and durability at reduced cost. The 10-kW-scale cell stack building blocks will be housed within a hermetically sealed "hotbox" to reduce drastic changes in temperature and pressure during operation. These design features would allow for seamless integration with a turbine or combustion engine to maximize the overall efficiency of a hybrid system.
Northrop Grumman Aerospace Systems
FSPOT-X: Full Spectrum Power for Optical/Thermal Exergy
Northrop Grumman Aerospace Systems is developing a dish-shaped sunlight-concentrating hybrid solar converter that integrates high-efficiency solar cells and a thermo-acoustic engine that generates electricity directly from heat. Current solar cells lose significant amounts of energy as heat, because they do not have heat storage capability. By integrating a high-temperature solar cell and thermo-acoustic engine into a single system, thermal energy losses are minimized. The thermo-acoustic unit, which was originally designed for space missions, converts waste heat from the solar cell into sound waves to generate electricity using as few moving parts as possible. The engine and solar cell are connected to a molten salt thermal storage unit to store heat when the sun shines and to release the heat and make electricity when the sun is not shining. Northrop Grumman's system could efficiently generate electricity more cheaply than existing solar power plants and lead to inexpensive, on-demand electricity from solar energy.
Oak Ridge National Laboratory
A Natural-gas based High Efficiency Combined Thermo-chemical Affordable Reactor (NECTAR)
Oak Ridge National Laboratory
Nanocomposite Electrodes for a Solid Acid Fuel Cell Stack Operating on Reformate
Oak Ridge National Laboratory (ORNL) is redesigning a fuel cell electrode that operates at 250ºC. Today's solid acid fuel cells (SAFCs) contain relatively inefficient cathodes, which require expensive platinum catalysts for the chemical reactions to take place. ORNL's fuel cell will contain highly porous carbon nanostructures that increase the amount of surface area of the cell's electrolyte, and substantially reduce the amount of catalyst required by the cell. By using nanostructured electrodes, ORNL can increase the performance of SAFC cathodes at a fraction of the cost of existing technologies. The ORNL team will also modify existing fuel processors to operate efficiently at reduced temperatures; those processors will work in conjunction with the fuel cell to lower costs at the system level. ORNL's innovations will enable efficient distributed electricity generation from domestic fuel sources using less expensive catalysts.
Ocean Renewable Power Company
Innovative Deployment and Retrieval Scheme for Cross-flow Hydrokinetic Turbines
The Ocean Renewable Power Company (ORPC) will develop an innovative, self-deploying MHK power system, which will reduce the operating costs and improve the efficiency of MHK systems by up to 50%. ORPC's system is based on pitch control of the blades of a cross-flow turbine, in which the tidal flow passes across the turbine blades rather than in a radial fashion. This system will allow the turbine to self-propel itself to the deployment location, and lower itself to the sea floor remotely. This innovative approach will allow for lower costs of deployment and retrieval, reduced requirements for sea-bed foundation construction, as well as increased turbine efficiency. The ORPC team will design, build, and test a model scale of the MHK system to demonstrate the benefits of using a self-deploying turbine, before completing the design and cost analysis of the full-scale commercial system. Successful deployment of this system would significantly reduce the LCOE associated with MHK systems, making the technology a viable renewable resource to generate electrical power.
Otherlab, Inc.
Adaptive Fluidic Solar Collectors
Otherlab is developing an inexpensive small mirror system with an innovative drive system to reflect sunlight onto concentrating solar power towers at greatly reduced cost. This system is an alternative to expensive and bulky 20-30 foot tall mirrors and expensive sun-tracking drives used in today's concentrating solar power plants. In order for solar power tower plants to compete with conventional electricity generation, these plants need dramatic component cost reductions and lower maintenance and operational expenses. Otherlab's approach uses a smaller modular mirror design that reduces handling difficulty, suffers less from high winds, and allows the use of mass manufacturing processes for low-cost component production. These mirrors can be driven by mechanisms that utilize simpler, more readily serviceable parts which decreases system downtime and efficiency. The incorporation of low-cost and highly-scalable manufacturing approaches could significantly reduce the cost of solar electricity generation below conventional solar tower plant technologies.
Palo Alto Research Center
Micro-Chiplet Printer for MOSAIC
Palo Alto Research Center (PARC), along with Sandia National Laboratory (SNL) will develop a prototype printer with the potential to enable economical, high-volume manufacturing of micro-PV cell arrays. This project will focus on creating a printing technology that can affordably manufacture micro-CPV system components. The envisioned printer would drastically lower assembly costs and increase manufacturing efficiency of micro-CPV systems. Leveraging their expertise in digital copier assembly, PARC intends to create a printer demonstration that uses micro-CPV cells or "chiplets" as the "ink" and arranges the chiplets in a precise, predefined location and orientation, similar to how a document printer places ink on a page. SNL will provide micro-scaled photovoltaic components to be used as the "ink," and the PARC system will "print" panel-sized micro-CPV substrates with digitally placed and interconnected PV cells. This micro-chiplet printer technology may reduce the assembly cost of micro-CPV systems by orders of magnitude, making them cost competitive with conventional FPV. To demonstrate the effectiveness of the printer, the project team will investigate two types of backplanes (electronically connected PV arrays arranged on a surface): one with a single type of micro-PV cell, and one with at least two types of micro-PV cells.
Panasonic R&D Company of America
Low Profile CPV Panel with Sun Tracking for Rooftop Installation
Panasonic Boston Laboratory will develop a micro-CPV system that features a micro-tracking subsystem. This micro-tracking subsystem will eliminate the need for bulky trackers, allowing fixed mounting of the panel. The micro-tracking allows individual lenses containing PV cells to move within the panel. As the sun moves throughout the day, the lenses align themselves to the best position to receive sunlight, realizing the efficiency advantages of CPV without the cumbersome tilting of the entire panel. The Panasonic Boston Laboratory team will examine a number of methods to allow the individual lenses to track the sunlight. Each panel will be comparable in thickness and cost to a traditional FPV panel.
Pennsylvania State University
Wide-Angle Planar Microtracking Microcell Concentrating Photovoltaics
Pennsylvania State University (Penn State), along with their partner organizations, will develop a high efficiency micro-CPV system that features the same flat design of traditional solar panels, but with nearly twice the efficiency. The system is divided into three layers. The top and bottom layers use a refractive/reflective pair of tiny spherical lens arrays to focus sunlight onto a micro-CPV cell array in the center layer. The micro-CPV arrays will be printed on a transparent sheet that slides laterally between the top and bottom layer to ensure that the maximum amount of sunlight is delivered to the micro-PV cell throughout the day. Advanced manufacturing using high-throughput printing techniques will help reduce the cost of the micro-CPV cell arrays and allow the team to create five-junction micro-PV cells that can absorb a broader range of light and promote greater efficiency. By concentrating and focusing sunlight on a specific advanced micro-PV cell, the system can achieve much higher efficiency than standard FPV panels, while maintaining a similar flat panel architecture.
Redox Power Systems, LLC
Low-Temperature Solid Oxide Fuel Cells for Transformational Energy Conversion
Redox Power Systems is developing a fuel cell with a mid-temperature operating target of 400°C while maintaining high power density and enabling faster cycling. Current fuel cell systems are expensive and bulky, which limits their commercialization and widespread adoption for distributed generation and other applications. Such state-of-the-art systems consist of fuel cells that either use a mixture of ceramic oxide materials that require high temperatures (~800°C) for grid-scale applications or are polymer-based technology with prohibitive low temperature operation for vehicle technologies. By combining advanced materials that have traditionally been unstable alone, Redox will create a new two-layer electrolyte configuration incorporating nano-enabled electrodes and stable ceramic anodes. The use of these materials will increase system power density and will have a startup time of less than 10 minutes, making them more responsive to demand. Redox is also developing a new fuel processor system optimized to work with their low-temperature solid oxide fuel cells. This new material configuration also allows the operating temperature to be reduced when incorporated into commercially fabricated fuel cells. These advances will enable Redox to produce a lower cost distributed generation product, as well as to enter new markets such as embedded power for datacenters.
RedWave Energy, Inc.
High Speed Diode and Rectenna for Waste Heat to Electricity Harvesting
The team led by RedWave Energy will develop a waste heat harvesting system, called a rectenna, that converts low-temperature waste heat into electricity. Rectennas are nanoantennas that convert radiant energy to direct current (DC) electricity. The rectennas are fabricated onto sheets of flexible material in tightly packed arrays and placed near key heat sources such as the turbine's condenser, heat exchanger, and flue gas cooling stack. Heat radiates onto the nanoantennas and energizes electrons on the antennas' surface. These electrons are rectified by the system, resulting in DC power. This technology will target the waste heat in industrial processes and thermoelectric power generation.
SAFCell, Inc.
Solid Acid Fuel Cell Stack for Distributed Generation Applications
SAFCell is developing solid acid fuel cells (SAFCs) that operate at 250 °C and will be nearly free of precious metal catalysts. Current fuel cells either rely on ultra-pure hydrogen as a fuel and operate at low temperatures for vehicles technologies, or run on natural gas, but operate only at high temperatures for grid-scale applications. SAFCell's fuel cell is utilizing a new solid acid electrolyte material to operate efficiently at intermediate temperatures and on multiple fuels. Additionally, the team will dramatically lower system costs by reducing precious metals, such as platinum, from the electrodes and developing new catalysts based on carbon nanotubes and metal organic frameworks. The proposed SAFC stack design will lead to the creation of low cost fuel cells that can withstand common fuel impurities, making them ideal for distributed generation applications.
Saint-Gobain Ceramics and Plastics, Inc.
Super High-efficiency Integrated Fuel-cell and Turbo-machinery - SHIFT
Saint-Gobain will combine a pressurized all-ceramic solid oxide fuel cell (SOFC) stack with a custom-designed screw compressor and expander to yield a highly efficient SOFC and Brayton cycle hybrid system. In this configuration, the SOFC stack generates most of the system's electric power. The expander converts a portion of the stack's waste exergy to additional electric power. Saint-Gobain and its partners will integrate three enabling technologies: Saint-Gobain's robust all-ceramic SOFC stack, Brayton Energy LLC's rotary screw engine (compressor and expander), and Precision Combustion Inc.'s (PCI) SOFC-reformer integrated hotbox. Due to its monolithic nature, the all-ceramic stack enables high pressure, efficient operation, and long-term durability that may provide a 20-year life without stack replacement. Saint-Gobain will develop low-cost ceramic forming techniques to link to its multi-cell co-sintering process. The screw components developed in this program would eliminate the risk of pressure surges during operation. This is a common problem with conventional gas turbines, which can potentially damage SOFC stacks. Finally, PCI's unique hotbox will allow pressurized operation of the SOFC stack and maximize heat transfer and waste heat capture to minimize energy losses. This project will potentially introduce a new distributed, high durability, and enhanced lifetime electricity production system capable of 70% efficiency.
Sencera Energy, Inc.
Kinematic Flexure-Based Stirling-Brayton Hybrid Engine Generator for Residential CHP
Sencera Energy and Ohio University will develop a novel kinematic Stirling-Brayton hybrid engine using flexure based volume displacement in lieu of a conventional piston-cylinder Stirling engine. A Stirling engine uses a working gas housed in a sealed environment, in this case the working gas is helium. When heated by the natural gas-fueled burner, the gas expands causing a piston to move and interact with an alternator to produce electricity. As the gas cools and contracts, the process resets before repeating again. Advanced Stirling engines endeavor to carefully manage heat inside the system to make the most efficient use of the natural gas energy. The flexure-based design achieves the same function as a piston-cylinder set by simply changing the volume of the working spaces, as opposed to sliding a piston along the interior of a cylinder. The removal of pistons from the design eliminates the need for sliding seals such as piston rings or air/gas bearings, resulting in lower engine friction, less fluid flow loss and fewer dead volumes. It also lowers the potential fabrication cost compared to other heat engines. The proposed kinematic engine design provides easy coupling to existing rotary alternator designs, which allows the use of robust, mature, and cost-effective off-the-shelf alternator technologies and controllers.
Sunpower, Inc.
Free Piston Stirling Engine Based 1kW Generator
Sunpower, in partnership with Aerojet Rocketdyne and Precision Combustion Inc. (PCI), proposes a high-frequency, high efficiency 1 kW free-piston Stirling engine (FPSE). A Stirling engine uses a working gas such as helium, which is housed in a sealed environment. When heated by the natural gas-fueled burner, the gas expands causing a piston to move and interact with a linear alternator to produce electricity. As the gas cools and contracts, the process resets before repeating again. Advanced Stirling engines endeavor to carefully manage heat inside the system to make the most efficient use of the natural gas energy. New innovations from this team include the highly efficient and high frequency design which reduces size and cost and can be wall mounted. The heater-head assembly acts as the heat exchanger between the burner and the enclosed working gas, and the higher temperature allows for greater efficiency. Aerojet Rocketdyne will assist this effort by developing high temperature materials to use in this process, while PCI will add a novel catalytically-assisted, two-stage, burner to maximize heat transfer to the heater-head.
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