Early production at Crescent Dunes, the new solar power tower plant with integrated energy storage, has been meager, but developer SolarReserve says not to worry, things are going according to plan.
Crescent Dunes began selling energy to the Nevada electric utility NV Energy last October, sporadically until the end of 2015, then a bit more regularly in 2016. Still, through March the highest monthly output was February’s 9,095 megawatt hours, according to Federal Energy Regulatory Commission reports. That’s a capacity factor of 11.9 percent for the month, a long way from the 52 percent overall capacity factor expected at Crescent Dunes in the long run.
Via email, I asked SolarReserve’s vice president of communications, Mary Grikas, what was up. She said the plant, in The Middle of Nowhere, Nevada, is purposefully pursuing a “deliberate ramp-up.”
“We’re not required under our PPA with NV Energy to be fully ramped up until January 2017 so we’re taking things slowly,” Grikas said. “This was also accounted for in our financial modeling, so we’re meeting our commitments both to NV Energy, as well as meeting our revenue requirements.”
A fully ramped up Crescent Dunes is promising 500,000 MWh a year from its single 110-megawatt tower surrounded by more than 10,000 heliostats. Pound for pound, that would make it a heavier hitter than the three-unit, 377-MW, direct-steam Ivanpah plant, whose backers once talked of producing around 975,000 MWh annually but now would be happy to reach 780,00 MWh, the sum of the plant’s long-term minimum contractual obligations. (Energy storage also means Crescent Dunes doesn’t require the substantial natural gas that Ivanpah gobbles up to prime the system in the morning and keep it from locking up overnight.)
But that’s assuming it all works. Crescent Dunes isn’t the first plant of its type — the 20-MW Gemasolar tower in Spain has been in operation since April 2011, seemingly without issue, although I’ve been unable to determine if it has reached its annual generation target of 110,000 MWh/year — but it does represent a big scale-up of the basic technology.
Crescent Dunes took longer to build and commission than expected, so it will be interesting to see if it can indeed hit full stride next year. Lots of interested parties will presumably be watching closely. SolarReserve’s technology is proving to be attractive around the world, with a 100-MW project under construction in South Africa and another, a tower/PV combo totaling 260 MW, planned for Chile. And just last week, SolarReserve signed a memorandum of understanding with the state-owned Shenhua Group “to build 1,000 megawatts of solar thermal projects in China.”
Crescent Dunes cost about $1 billion to build. In March, CEO Kevin Smith told SoCal Tech “we’re looking to cut costs 30 to 40 percent with the next group” of projects. For that kind of money — $650 million, say — you could build 350 MW of PV, and in a sunny Southwest U.S. location generate around 900,000 MWh annually.
That’s more than what Crescent Dunes hopes to deliver, true, but PV electricity has value challenges. There’s lots of it at the same time, it peaks around noon, and is largely a nonfactor come dinnertime, when demand remains high during summer in the West. Crescent Dunes, with its molten salt storage, plans to hum into the evening, giving the utility power when it wants it (not forcing it to take the power whenever it arrives).
If it succeeds as efficiently as planned, with costs coming down, Crescent Dunes might even be enough to give power towers a chance again in the United States, where planned projects have fallen by the wayside.
First, though, there’s this shakeout period, in which production seems to be an afterthought to testing, learning and fixing.
Grikas said the sophisticated software at the plant is working fine and “the core technology continues to perform quite well, with the molten salt receiver performing above the expected efficiency curve.” The work, she said, is in “getting the balance of system components in a first-of-its-kind facility up to full speed.”
She went on to say: “On a day-to-day basis, we have a punch list of items that we’re going through — similar to any type of new construction. We’re also running through various operational scenarios to ensure that the plant operators thoroughly know all the procedures and are comfortable with operating the facility under various conditions, which will in the long run help to maximize output.”