Energies Media
At peak daylight in the Mojave Desert, the $2.2 billion Ivanpah Solar Electric Generating System looks like an engineering triumph: three 450-foot towers illuminated by thousands of gleaming mirrors.
Yet beneath that glittering facade lies one of California’s most expensive clean energy dilemmas. Utilities want to abandon the troubled 392-megawatt facility, but state regulators refuse to let them walk away.
Now, four researchers from the National Renewable Energy Laboratory have devised a turnaround strategy that could rescue the site from premature closure.
Pacific Gas & Electric and Southern California Edison are seeking to exit their 25-year power purchase agreements early. The utilities cite chronic underperformance and operating costs that no longer make financial sense.
However, the California Public Utilities Commission has repeatedly rejected their exit requests.
California mandates 60% renewable electricity by 2030, and taking 392 megawatts offline creates a major policy setback. Regulators also point to hundreds of millions of dollars in transmission infrastructure tied to Ivanpah that would be wasted.
Furthermore, replacing Ivanpah with new solar projects is hindered by equipment tariffs, tax credit uncertainties, and lengthy permitting delays.
Ivanpah’s central vulnerability stems from a fundamental design flaw: a direct-steam system built without thermal energy storage.
Since opening in 2014, the plant has delivered only 70% to 80% of its expected annual generation. Passing clouds frequently halt the steam turbines, forcing operators to burn natural gas to restart the power cycle.
Without storage, Ivanpah must sell electricity during midday hours when cheap photovoltaic solar floods California’s grid, pushing spot prices down to zero or negative levels.
Yet one critical component performed exceptionally well: the field of 173,500 tracking mirrors achieved 92% to 94% operational availability. The solar collection field was never the problem; the failure was how collected heat was processed and monetized.
To break the deadlock, researchers evaluated repurposing Ivanpah’s existing infrastructure rather than bulldozing it. The plan retains the high-performing mirror field and central towers while replacing the outdated direct-steam boilers.
By installing a modern molten-salt receiver, the facility can capture high-temperature solar energy and transfer it into thermal storage. This system connects the mirror array to a two-tank molten-salt system capable of storing 12 hours of energy.
Instead of dumping power during midday price troughs, the plant can hold its heat and generate electricity when grid demand peaks after dark.
When Ivanpah was built, midday solar power still commanded strong market prices. As low-cost solar panels saturated global grids, international developers adapted by making molten-salt thermal storage standard on central tower projects.
Global energy markets in China, Morocco, and Israel quickly built standardized 100-megawatt solar towers paired with thermal storage.
Firms like China Three Gorges Renewables and CNNC HuiNeng gained extensive experience operating large-scale thermal storage systems. Ivanpah remained isolated as a first-generation relic, incapable of shifting generation to match evening price spikes.
This operational gap left the Mojave facility financially stranded while international peers demonstrated the profitability of dispatchable solar thermal energy.
Here is the final breakthrough revealed by the researchers’ financial modeling: retrofitting Ivanpah transforms a failing asset into a high-yield power plant.
Assuming the existing towers and mirror arrays are treated as sunk costs, the upgraded facility achieves a 30% higher internal rate of return than Ivanpah’s historical baseline. At 2024 grid schedules, the retrofitted plant could deliver dispatchable power at a competitive rate as low as 6.99 cents per kilowatt-hour.
This conversion proves that legacy clean energy assets retain immense salvage value when adapted to modern market conditions.
By converting a stranded direct-steam plant into a dispatchable 12-hour thermal storage giant, four researchers have handed California a blueprint to save its Mojave Desert facility.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.

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