solar-plus-storage
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Stem and the Art of Selling Less
The clean energy company made its name helping batteries choose their moment. Its own turning point came when it decided that selling more batteries was the wrong ambition.
The Solar Company That Bet on the Buildings Everyone Else Skipped
Isaac Baker and Ben Underwood built a solar company around the customers the industry finds too poor or too complicated. Nearly a decade in, the affordable-housing rooftops are paying them back.
Terrajoule Energy Inc
Terrajoule Energy is a Palo Alto cleantech company building modular, dispatchable solar power stations that deliver clean electricity around the clock without lithium-ion batteries. Its patented Dispatchable Solar Module (DSM) pairs prefabricated Linear Fresnel solar concentrators with a Steam Accumulator Energy Storage (SAES) system - storing energy as pressurized hot water in steel pressure vessels - and reciprocating steam piston engines to turn steam into electricity. The pitch is blunt: store energy in steel and water instead of rare metals, and undercut the cost of PV-plus-battery from day one. Founded by electrical engineer and serial hardware entrepreneur Stephen J. Bisset, Terrajoule raised an $11.5M Series A from NEA and Air Liquide's ALIAD, and was acquired by Environmental Clean Technologies Limited in December 2025.