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Fourth Power
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Develops modular high-density thermal energy storage
Fourth Power
Work Here?
Develops modular high-density thermal energy storage
Overview
Fourth Power develops a thermal battery system for utility-scale energy storage. It stores excess wind and solar energy at very high temperatures to provide reliable power when needed, with a high power density and modular design. The subsystems sit in an argon environment to prevent fire risk and chemical degradation, enabling safe, scalable operation where energy and power can be scaled independently. The company differentiates itself by offering a cost-competitive, scalable solution aimed at utilities and regulators, rather than consumers, positioning renewable energy storage as a cost-effective alternative to fossil fuels. Its goal is to make renewable energy the most affordable and accessible source of power through advanced thermal storage technology, working with utility companies and government partners to broaden adoption.
About Fourth Power
Industries
Hardware
Industrial & Manufacturing
Energy
Company Size
11-50
Company Stage
Series A
Total Funding
$39M
Headquarters
Cambridge, Massachusetts
Founded
2021
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Simplify's Take
What believers are saying
- Fourth Power says three utilities signed letters of interest by December 2023.
- Arvin Ganesan said a Massachusetts pilot commissions this year, de-risking commercialization.
- AI and electrification drive utility demand for long-duration storage and peaker replacement.
What critics are saying
- The Boston demo is still commissioning in 2026, delaying revenue until 2028.
- Utilities demand bankable proof; one failed pilot kills financing and commercial credibility.
- Lithium-ion, pumped hydro, and sodium-ion vendors already own procurement channels and interconnection teams.
What makes Fourth Power unique
- Fourth Power stores grid electricity as 2,400°C heat in carbon blocks.
- Its compact 25 MW modules fit football-field sites near urban load centers.
- The design separates subsystems in argon, avoiding fire and chemical-degradation risks.
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Funding
Total Funding
$39M
Above
Industry Average
Funded Over
2 Rounds
Industry standards
Growth & Insights and Company News
6 month growth
↑ 0%1 year growth
↑ 0%2 year growth
↑ 0%Munich Re has invested in Fourth Power, a company that develops energy storage systems. These systems store electricity as heat in carbon blocks and convert it back to electricity when required.
As utilities face surging demand from electrification and the advancement of artificial intelligence, Fourth Power, a flexible-duration energy storage provid...
Tim Crino from Inc. on how Fourth Power's $20M Series A Plus, led by Munich Re Ventures, will be used to achieve commercial viability and build out a sales and partnerships pipeline.
Fourth Power has raised $20 million in Series A Plus funding, led by Munich Re Ventures, to commercialize its utility-scale thermal energy storage system. The system offers a 10x cost advantage over lithium-ion batteries and scales from 5 to 100+ hours. The funding will support a 1 MWh-e demonstration and deepen partnerships. Fourth Power's technology uses 2400°C liquid metal for heat transfer, achieving high power density and reducing costs to less than $25/kWh-e.
BOSTON-(BUSINESS WIRE)-To support the rapidly growing demand for clean, firm power, grid energy storage pioneer Fourth Power has added Fred Huang and Patrick Schweiger to the senior leadership team as Executive Vice Presidents (EVPs).
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About Fourth Power
Industries
Hardware
Industrial & Manufacturing
Energy
Company Size
11-50
Company Stage
Series A
Total Funding
$39M
Headquarters
Cambridge, Massachusetts
Founded
2021
There are no jobs for Fourth Power right now.
Find jobs on Simplify and start your career today