Fourth Power

Fourth Power develops thermal battery technology that stores heat at high temperatures for industrial decarbonisation and grid flexibility.

Where it wins

• Replaces fossil-fuel boilers in industrial processes with stored thermal energy, cutting carbon emissions and energy costs.
• Provides long-duration energy storage (days to weeks) at a fraction of the cost of lithium-ion batteries, addressing grid-scale intermittency.
• Uses abundant, low-cost materials (sand, ceramics) instead of critical minerals, reducing supply chain risk and environmental impact.

Credibility: Founded by MIT professor Dr. Asegun Henry, a leading expert in thermal energy storage, and Arvin Ganesan, with a $45M seed round led by prominent climate investors.

• Sells modular thermal battery hardware that stores excess renewable electricity as high-temperature heat, then discharges it as steam or hot water on demand.
• Targets industrial heat (a major source of global emissions) and grid-scale storage, leveraging low-cost, abundant materials to achieve cost parity with fossil fuels.
• Unit of value is stored thermal energy (kWh-thermal), with margins driven by hardware scale and software optimisation of charge/discharge cycles.

• Competes with lithium-ion battery providers (e.g., Tesla, Fluence) for grid storage, offering lower cost and longer duration.
• Competes with hydrogen and synthetic fuel solutions for industrial heat, offering simpler integration and higher round-trip efficiency.
• Competes with electric boilers and heat pumps, offering higher temperature output suitable for heavy industry. Differentiators: Uses abundant materials, achieves higher temperatures than most electric alternatives, and targets both industrial heat and grid storage.

• Industrial manufacturers face high carbon taxes and rising natural gas prices, necessitating cost-effective decarbonisation of process heat.
• Grid operators struggle with renewable intermittency, lacking affordable long-duration storage solutions beyond lithium-ion.
• Critical mineral supply chains for batteries are volatile and environmentally damaging, creating ESG and cost risks.

Fourth Power’s wedge is industrial process heat, a hard-to-abate sector with urgent decarbonisation pressure. The main risk is scaling manufacturing and proving reliability at commercial scale. The opportunity lies in grid storage, where long-duration needs are growing. The next signal would be a signed offtake agreement with a major industrial customer or utility.

Develop a clear pricing model and unit economics to attract enterprise buyers. Expand partnerships with industrial equipment OEMs to embed thermal batteries into new heating systems. Target specific high-heat industries (e.g., cement, steel) with tailored solutions to accelerate adoption. Publish third-party validation of energy density and cost metrics to build credibility against incumbents.