Fourth Power’s Thermal Batteries Could Undercut Natural Gas Plants
▼ Summary
– Fourth Power is developing thermal batteries using superheated liquid tin and argon-filled chambers to store energy cheaply for 24/7 solar and wind power.
– The system stores energy by heating carbon blocks with electricity and releases it by pumping molten tin through graphite pipes, converting heat back to electricity via thermophotovoltaic cells.
– The startup plans to build its first full-scale battery and deliver commercial-scale units by 2028, aiming to undercut lithium-ion batteries and natural-gas plants in cost.
– The batteries are designed for daily charging and discharging, providing continuous electricity for around eight hours or more, twice as long as typical grid-scale lithium-ion batteries.
– Fourth Power has raised $20 million in a Series A Plus funding round to build a 1-megawatt-hour demonstration battery and projects costs could eventually fall to $25 per kilowatt-hour.
Fourth Power is pioneering a thermal battery technology that could revolutionize long-duration energy storage, potentially making solar and wind power more economically viable than natural gas plants. This innovative system uses superheated liquid tin and argon-filled chambers to store and release energy with remarkable efficiency.
The process begins when electricity from the grid heats carbon blocks within insulated, argon-rich chambers. To discharge energy, the system pumps molten tin heated to an extreme 2,400°C (4,352°F) through specialized graphite pipes, the only affordable material capable of enduring such intense temperatures. Thermophotovoltaic cells, similar in concept to solar panels, then capture the infrared light emitted by the glowing tin and convert it back into usable electricity.
Based in Cambridge, Massachusetts, the four-year-old startup has spent the last two years perfecting this technology and is now preparing to construct its first full-scale battery. If development proceeds as planned, Fourth Power aims to deliver commercial-scale units to customers by 2026, potentially undercutting both lithium-ion batteries and natural gas peaker plants on cost.
According to Arvin Ganesan, co-founder and CEO of Fourth Power, the company’s projections indicate that its first-to-market systems will be cost-competitive from the outset. The technology is designed for daily charging and discharging cycles, supplying continuous power for approximately eight hours or longer, twice the duration of most grid-scale lithium-ion batteries. A key to its efficiency lies in the insulation, made from petroleum coke, a waste product from oil refining, which limits energy loss to just 1% per day.
The company is currently conducting extensive tests on smaller versions of the system to verify power output and durability. In parallel, Fourth Power is designing a 1-megawatt-hour demonstration battery. To fund this project, the startup has secured $20 million in a Series A Plus funding round led by Munich Re Ventures, with participation from Breakthrough Energy Ventures and DCVC. This follows a $19 million Series A round raised in 2023.
Looking ahead, Fourth Power anticipates that large-scale production could drive the cost of electricity storage down to $25 per kilowatt-hour, a mere tenth of the cost associated with lithium-ion batteries. Ganesan emphasizes that the simplicity of the system and a streamlined supply chain make this ambitious target achievable. With fewer moving parts and limited reliance on complex components, the path to affordability appears clear and direct.
(Source: TechCrunch)
