Distributed Generation

George Washington University (GWU) will develop a new technique to produce commercial III-V substrates called Transfer Printed Virtual Substrates (TPVS). To reduce costs, the team proposes using a single source substrate to grow numerous virtual substrate layers. The team will use an enabling technology, called micro-transfer printing (MTP), to transfer the layers from the source substrate, in the form of many microscale "chiplets," and deposit them onto a low-cost handle (silicon, for example). Once printed, the clean surfaces of the MTP process allows each chiplet to complete the epitaxial growth process on the lower cost substrate after having been seeded from the initial source and having sacrificial layers in between to release the chiplets from the source wafer. The TPVS process can potentially yield tens to hundreds virtual substrates from a single source wafer. Any micro/nanoscale device grown on III-V substrates, such as sensors, detectors, lasers, power electronics, and high-speed transistors, will experience significant cost reductions as a direct result of TPVS deployment. TPVS can also reduce the demand for rare minerals used for a wide range of critical technological applications due to the greater efficiency with which each initial source substrate is utilized.

Georgia Tech Research Corporation is developing a high-efficiency concentrating solar receiver and reactor for the production of solar fuels. The team will develop a system that uses liquid metal to capture and transport heat at much higher temperatures compared to state-of-the-art concentrating solar power facilities. This high temperature system will be combined with the team's novel reactor to produce solar fuels that allow the flexibility to store and transport solar energy for later use or for immediate power production. Higher temperatures should result in much higher efficiencies and therefore lower costs of produced fuel or electricity. Additionally, plant operators would have the flexibility to match electricity or fuel production with the changing market demand to improve the cost effectiveness of the plant.

Glint Photonics is developing an inexpensive solar concentrating PV (CPV) module that tracks the sun's position over the course of the day to channel sunlight into PV materials more efficiently. Conventional solar concentrator technology requires complex moving parts to track the sun's movements. In contrast, Glint's inexpensive design can be mounted in a stationary configuration and adjusts its properties automatically in response to the solar position. By embedding this automated tracking function within the concentrator, Glint's design enables CPV modules to use traditional mounting technology and techniques, reducing installation complexity and cost. These self-tracking concentrators can significantly decrease the cost of solar power modules by enabling high efficiency while eliminating the additional costs of precision trackers and specialized mounting hardware. The concentrator itself is designed to be manufactured at extremely low-cost due to low material usage and compatibility with high-speed fabrication techniques. Glint's complete module costs are estimated to be $0.35/watt-peak.

PV inverters convert DC power generated by modules into usable AC power. Ideal Power's initial 30kW 94lb PV inverter reduces the weight of comparable 30kW PV inverters by 90%--reducing the cost of materials, manufacturing, shipping, and installation. With ARPA-E support, new bi-directional silicon power switches will be developed, commercialized, and utilized in Ideal Power's next-generation PV inverter. With these components, Ideal Power will produce 100kW inverters that weight less than 100lb., reducing the weight of conventional 3,000lb. 100kW inverters by more than 95%. The new power switches will cut IPC's $/W manufacturing cost in half, as well as further reduce indirect shipping and installation costs.

The team led by Iowa State University (ISU) will develop an All Solid-State Sodium Battery (ASSSB) that will have a high energy content, can easily be recycled, and rely on highly abundant and extremely low cost starting materials. Commercially available sodium-based batteries operate at elevated temperatures, which decreases the efficiency and safety of the system. The team seeks to improve all three of the main components of a sodium-based battery: the anode, cathode, and electrolyte separator. The team's anode is a porous carbon nanotube layer that will serve as a framework on which sodium metal will be deposited. The separator will be made of a novel oxy-thio-nitride glass solid electrolyte, and the cathode will be composed of a polymer in which reversible sodium insertion and removal takes place. The team will need to overcome several challenges, including reducing interfacial resistance between the organic electrode and the solid electrolyte. The proposed sodium battery can operate at room temperature, uses a benign and scalable solid-stack design for a long cycle life, and expects to achieve an energy density eqivalent to state-of-the-art Li-ion cells.

MAHLE Powertrain with partners at Oak Ridge National Laboratory, Louthan Engineering, Kohler Company, and Intellichoice Energy will design and develop a CHP generator that uses an internal combustion engine with a turbulent jet ignition (TJI) combustion system. Similar to an automotive internal combustion engine, the proposed system follows the same process: the combustion of natural gas fuel creates a force that moves a piston, transferring chemical energy to mechanical energy used in conjunction with a generator to create electricity. The TJI combustion system incorporates a pre-chamber combustor, enabling the engine to operate in ultra-lean conditions (i.e. high air to fuel mixture), which results in significant improvement in engine thermal efficiency. The team will further increase the system's efficiency by using low friction engine components, while a low-temperature after-treatment system will reduce exhaust emissions.

The Massachusetts Institute of Technology (MIT) with partner Arizona State University will develop a new concept for PV power generation that achieves the 30% conversion efficiency associated with traditional concentrated PV systems while maintaining the low cost, low profile, and lightweight of conventional FPV modules. MIT aims to combine three technologies to achieve their goals: a dispersive lens system, laterally arrayed multiple bandgap (LAMB) solar cells, and a low-cost power management system. The dispersive lens concentrates and separates light that passes through it, providing 400-fold concentration for direct sunlight and 3-fold concentration for diffuse sunlight. The dispersive lens is a thin layer consisting of inexpensive, lightweight materials that can be manufactured at low cost using plastic molding, an improvement over traditional methods. The lens focuses the direct light onto the array of LAMB solar cells, while also focusing the diffuse light onto common PV cells integrated beneath the LAMB array. The power management system combines power from multiple cells into a single output so that the power from a panel of LAMB arrays can be processed with grid-interface power electronics, enabling as much as 20% additional energy capture in applications where the roof is partially shaded.

Massachusetts Institute of Technology (MIT) is developing a hybrid solar converter that integrates a thermal absorber and solar cells into a layered stack, allowing some portions of sunlight to be converted directly to electricity and the rest to be stored as heat for conversion when needed most. MIT's design focuses concentrated sunlight onto metal fins coated with layers that reflect a portion of the sunlight while absorbing the rest. The absorbed light is converted to heat and stored in a thermal fluid for conversion to mechanical energy by a heat engine. The reflected light is directed to solar cells and converted directly into electricity. This way, each portion of the solar spectrum is directed to the conversion system where it can be most effectively used. The sunlight passes through a transparent microporous gel that also insulates each of the components so that the maximum energy can be extracted from both the heat-collecting metal fins and the solar cells. This unique stack design could utilize the full solar spectrum efficiently and enable the dispatch of electricity at any time of the day.

Materials & Systems Research, Inc. (MSRI) is developing an intermediate-temperature fuel cell capable of electrochemically converting natural gas into electricity or liquid fuel in a single step. Existing solid-oxide fuel cells (SOFCs) convert the chemical energy of hydrocarbons--such as hydrogen or methane--into electricity at higher efficiencies than traditional power generators, but are expensive to manufacture and operate at extremely high temperatures, introducing durability and cost concerns over time. Existing processes for converting methane to liquid transportation fuels are also capital intensive. MSRI's technology would convert natural gas into liquid fuel using efficient catalysts and a cost-effective fabrication process that can be readily scaled up for mass production. MSRI's technology will provide low-cost power or liquid fuel while operating in a temperature range of 400-500ºC, enabling better durability than today's high-temperature fuel cells.