The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is focused on developing an energy storage technology that stores electricity as heat and converts its back to electricity whenever needed using thermophotovoltaics (TPV). If successful, the innovation will help transition the United States (US) towards a fully renewable electrical grid. The company is developing one of the only battery technologies able to deliver a cost per unit energy (CPE) for energy storage that will enable the use of renewables by the electrical grid. The innovation will also reduce the production of carbon dioxide (CO2) during the production of electricity and may do the same for transportation and industrial processes. The solution will also support the USs national defense by increasing the economic manufacturing competitiveness of the US and improving energy security, as well as enabling utility customers to benefit from significant cost savings._x000D_ _x000D_ The intellectual merit of this project is focused on the development of a thermal battery system that takes electricity from any source and converts it to extremely high-temperature sensible heat in inexpensive graphite blocks. The innovative feature is its ability to decouple power and energy, enabling any discharge duration between 1-100 hours. Currently, no other system can achieve such great and variable discharge levels at such low cost. The company will build two test rigs to test the pumps, pipes, joints, and valves, and then to test the thermophotovoltaics modules under aggressive thermal cycling conditions. The technical objectives are to: (1) set up the induction furnace system to prescreen materials and components; (2) determine which grades of graphite from large-scale suppliers can meet the specifications of future commercial demonstrations; (3) pre-screen approaches to sealing; (4) quantify the reaction strength of the bonding agent and determine how it can be used in products; and, (5) verify that the system installed seals sufficiently well so that future test loop work will not be delayed. The prototypes hardware will be scaled-up and the critical components will be stress-tested. The company has already developed a fully-functioning, integrated system at a small scale, 1-10 kilowatt-hour-electric (kWh-e), that works as a proof-of-concept. The reliability of the full-scale hardware in the test loop must be demonstrated prior to building a 1 megawatt-hour-electric (MWh-e) scale demonstration. The company is developing one of the only battery technologies able to deliver a cost per unit energy (CPE) of less than$25/kWh-e for energy storage which will enable the full penetration of renewables onto the electrical grid._x000D_ _x000D_ This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.