The archive
Writing
Essays and explainers on energy storage, battery chemistry, and the economics of holding clean power until it is needed.
Explainer Why vanadium flow batteries age differently Vanadium flow stores energy in liquid tanks that don't degrade like electrodes do. That difference in aging changes the economics of long-duration storage. Essay The storage that gravity built Pumped hydro is the largest form of grid storage on Earth. The reason it rarely appears in battery coverage is geography, not performance. Essay The battery that wasn't finished Retired EV packs still have useful capacity. Repurposing them for grid storage is a genuine opportunity, and a genuinely difficult engineering problem. Essay What zinc-ion gets right about grid storage Zinc-ion batteries use water as their electrolyte, which sounds like a problem and turns out to be the point. The safety and materials case is real; the cycle life question is not yet closed. Explainer The supply chain argument for sodium-ion Sodium-ion batteries do not beat lithium-ion on performance. For stationary storage, they may not need to. The case is about where the materials come from. Essay The case for storing heat instead of electricity A hot water tank is a battery for heat loads, with no round-trip conversion losses. That matters more than grid planners typically acknowledge. Essay When the wind doesn't blow for a week The four-hour battery solves the evening peak. The multi-day calm is a different problem, and the technologies competing to solve it look nothing like lithium-ion. Essay In praise of boring batteries The battery that will decarbonize the grid is unlikely to be the exciting one. For storage that never moves, cheap, safe, and durable beats dense and clever almost every time. Essay The grid's hardest hour is after sunset Why the defining challenge of a renewable grid is not making clean power but covering the few hours each evening when the sun is gone and demand is not.