Geothermal undercuts solar-plus-storage in Nevada utility filing

Three geothermal offers came in at 105 to 107 dollars per megawatt-hour in NV Energy's 2026 resource plan filing — about 7 percent below the capacity-weighted average of roughly 114 dollars for the eleven solar-plus-battery offers in the same document. The comparison comes from the sunniest state in the lower 48, where solar has spent a decade being described as unbeatable on cost.

Using the filing's corrected prices, the geothermal deals total 180 MW at a weighted average of 105.56 dollars per MWh, against 4,370 MW of solar-plus-storage at 113.89 dollars. The solar figure covers panels paired mostly with four-hour batteries. Joel Edwards, co-founder and CTO of geothermal developer Zanskar, posted on October 7 that "the flippening has come".

The direction of travel inside the filing matters as much as the level. The three solar-plus-storage projects NV Energy put forward in 2024 averaged about 94 dollars per MWh. Boulder Solar III's levelized price rose from about 85 dollars to about 125, which Edwards attributes to permitting delays, land carrying costs, higher financing costs and tariffs. Individual solar bids still came in lower — Sleepy Orange at 89.80 dollars, White Pine Solar at 101.92 — but the geothermal average beat the solar fleet.

The policy backdrop is doing most of the work. Under the One Big Beautiful Bill passed in 2025, wind and solar projects that did not begin construction by July 4, 2026 must be in service by the end of 2027 to claim federal tax credits. Geothermal, like battery storage, keeps the full federal credit for projects starting construction through 2033 — a much longer runway, in Edwards's words. A geothermal plant also runs day and night regardless of weather, and Edwards argues that twelve-plus hours of storage would cost more and still not cover multi-day gaps.

The buyers are already moving. Google is backing up to 150 MW of new Ormat geothermal through NV Energy; Amazon is backing 100 MW from Zanskar. Fervo's third-generation well design boosted drilling rates by 143 percent, and its latest Cape Station well was finished in 21 days. Big Oil-backed Mazama has placed a 135-million-dollar bet on superhot geothermal, its second well reaching 10,350 feet about 80 percent faster than its first.

Two of the three geothermal deals and two of the solar deals are sleeved contracts tied to specific large customers rather than open bids — the corporations, not the utility's ratepayers, are carrying the price risk. The mandates and subsidies built the solar fleet; in Nevada's own filings, the unsubsidised heat from underground is now cheaper than the sun.