Fourth Power stores electricity as heat and converts it back with light.
A utility-scale thermal storage system built from graphite, engineered to dispatch multi-day power quickly, safely and affordably.
Charge. Store. Discharge.
Step 1 — Charge:
Off-peak electricity powers resistive heaters that radiate heat to graphite blocks for storage
Step 2 — Store:
Heat is stored in graphite blocks within a heavily insulated, inert environment, resulting in minimal thermal loss for days or weeks at a time
Step 3 — Discharge:
On dispatch, the heat is thermally emitted as high-intensity light and converted to electricity using thermophotovoltaic cells
The Physics
At operating temperature, our core glows as bright as an old-fashioned incandescent filament. That glow is the whole point. Thermal radiation scales with the fourth power of temperature (to put that into perspective: this means doubling the heat results in sixteen times the light output). It's this nonlinear physics, not brute-force scale, that gives our high-temperature system its power density.
Services
Solutions
That glow is the whole point. Thermal radiation scales with the fourth power of temperature (to put that into perspective: this means doubling the heat results in sixteen times the light output). It's this nonlinear physics, not brute-force scale, that gives our high-temperature system its power density.
Power: 20 MW-e Storage: 1 GWh-e (50-hr baseline), scalable to 100+ hours Footprint: ~1 acre incl. balance of plant Dispatch: <10 seconds Lifespan: 30+ years Materials: graphite + TPV, domestic supply Environment: inert argon
• Breakthrough 1: High-temperature liquid metal pumping using all-graphite mechanical pumps — a Guinness World Record held by Fourth Power’s founder. • Breakthrough 2: Thermophotovoltaic cells exceeding 41% efficiency, leveraging advances originally designed at NREL. • Breakthrough 3: Patented emitter deposition prevention, solving the degradation problem that had limited TPV at scale.
