Overview
- Installed at Holmes Western Oil’s enhanced oil recovery site in Kern County, the 100 MWh unit is charged by a dedicated 20 MW off‑grid solar array and now operates automatically each day.
- After roughly 10 weeks of on-site testing, Rondo reports round‑trip efficiency above 97% and storage temperatures exceeding 1,000°C, delivering high‑pressure steam through existing lines.
- The heat battery runs alongside gas boilers with no retrofits and supplies around‑the‑clock steam by charging during roughly the six lowest‑cost hours of electricity each day.
- According to the company, displacing a natural‑gas boiler avoids about 13,000 metric tons of CO2 per year and enables credits under California’s Low Carbon Fuel Standard.
- Backed by Breakthrough Energy Ventures and Energy Impact Partners, Rondo is pursuing broader deployments across multiple regions, while some critics question using renewables to support oil production.