Munich Re backs Fourth Power

Fourth Power raised $20 million in a Series A+ round led by Munich Re Ventures , with participation from DCVC and Breakthrough Energy Ventures, bringing its total funding to nearly $40 million.

The Boston-based company’s system converts electricity into heat using liquid metal at 2400°C, stores it in carbon blocks, and converts it back to electricity via thermophotovoltaics. Built from domestic materials, the modular system is designed to scale from 5 to over 100 hours of storage at a cost below $25/kWh, offering utilities a lower-cost alternative to lithium-ion batteries.

The new funding will support the commissioning of a 1 MWh demonstration project using full-scale commercial components — the final step before customer deployments — and deepen supplier and utility partnerships ahead of expected commercial launches by 2027.