Solar Can Be Baseload: Spanish CSP Plant with Storage Produces Electricity for 24 Hours Straight

While Americans celebrated U.S. history on the Fourth of July yesterday, a company in Spain celebrated an historic moment for the solar industry: Torresol’s 19.9 MW concentrating solar power plant became the first ever to generate uninterrupted electricity for 24 hours straight.

The plant uses a Power Tower design which features a field of 2,650 mirrors that concentrate sunlight onto a boiler in a central receiver tower. The plant also utilizes molten salt as a heat-transfer fluid that allows the plant to generate electricity when there’s no sunlight. Recharge News reported on the milestone:

After commissioning in May, the plant was finally ready to operate at full-blast in late June and benefited from a particularly sunny stretch of weather, according to Diego Ramirez, director of production at Torresol.

“The high performance of the installations coincided with several days of excellent solar radiation, which made it possible for the hot-salt storage tank to reach full capacity,” Ramirez explains.

Torresol says that the plant will provide electricity for about 20 hours each day on average, with numerous days in the summer seeing 24-hours of supply. How does that compare with a similar-sized PV plant? The 21.2 MW Photovoltaic Solarpark Calaveron in Spain generates about 40 GWh a year. This smaller 19.9 MW power tower plant will generate about 110 GWh per year.


Yesterday’s news is a big milestone for Power Tower technology, which is still a very nascent technology compared to the more-mature parabolic troughs. There are only a few operating commercial-scale plants around the world, and Torresol’s is the only one with a 15-hour molten salt storage capability.

Further Reading:

Below are the earlier comments from the Facebook commenting system:

Michael Dunkley


July 6 at 3:22amJeffery Green

A small change would be to hook up natural gas and the plant uses fossil fuels only when needed.

July 9 at 12:32pmJ Peter Lynch

Congratulations. Storage is a subject that has generally been avoided, especially with PV systems, for years. We need breakthroughs in BOTH solar technologies and in storage to allow distributed solar systems to work…..great job…

July 7 at 10:09amEarl James

This is the kind of thinking and experimenting that we humans are capable of, and that could mitigate the doomsday meltdown rushing towards us! Too bad we have to deal with right wing greedheads in Congress who won’t move off the dime (or off their cash) and let human ingenuity have free rein. So “We can, but we won’t?” quote from my new novel Bella Coola: The Rainforest Brought Them Home, available on Amazon by July 25, 2011.,

July 6 at 1:37pmChuck Woolery

Very Freakin cool! Thanks for the info!

July 6 at 1:43pm

Chuck Woolery

Very Freakin cool! Thanks for the info!

July 6 at 1:43pm

Kurt Heinze

Energy storage is a key component of wind, solar, wave, tidal, etc… energy sources. We have generally been missing this point and making it easier for conservatives to dismiss “renewable” energy technologies like the aforementioned ones, allowing them to promote “clean coal” instead. All novel energy generating sources need to be coupled with energy storage or better yet a diversified portfolio of wind, solar, etc… that feeds into central/regional energy storage facilities might be a better approach. Once at the storage facility, the energy can be transferred into the grid when the demand it there. The question remains how much storage and what storage technologies are best. Unfortunately, this will not happen unless there are drastic changes made to our energies policies. Over subsidizing the fossil fuel industry will not allow for innovation, and without innovation, there will be no change. Society has come to a crossroad and needs to make a decision that will not only affect us but future generations. “I took the [road] less traveled by [a]nd that has made all the difference.” — Robert Frost from The Road Not Taken. I’m jumping down off my soapbox now.

July 17 at 7:03amRyan Scarrow

YES! This is my favorite renewable technology — I mean seriously, they’re melting salt into frickin’ lava. Combine this with more efficient buildings, photovoltaic panels, wind farms with flywheel storage, and natural gas turbines and you’ve got yourself the foundation for getting rid of coal altogether.

July 5 at 11:26amNicholas Jordan

The technology has never been the problem. Ford’s 1st car ran on hemp, which would be much easier to export to 3rd world countries than this solar tech. Hemp could easily replace dozens of environmentally hazardous industries. Which is why it is illegal.​d.shtml

July 5 at 11:57am

Paul Klemencic

Ryan, the salt stays molten all the time. This isn’t phase change material (PCM) storage. The molten salt mixture degrades at temperatures over 1050 deg F, and freezes at around 550 deg F. So a cold tank holds salt near the lower temperature, and the hot tank at the higher temperature. Molten salt acts both as a heat transfer fluid in the solar thermal collection system and as the thermal storage medium.


However, the costs of collecting heat in the solar thermal collection system can be beat by direct steam generation (DSG) systems. The use of the salt for thermal energy storage (TES) makes this system able to compete with the less expensive DSG systems.

July 10 at 8:12pm

Daniel Clark Orey

This is a great start… expensive now, but as thigns improve… every little bit helps… I wish there was a way to cover the roofs of big box stores and parking lots… again, every little bit helps…

July 5 at 1:30pmPierre Bull

Thanks for the heads up, Stephen, on this big milestone. One question for clarification: I’m not understanding the difference in total annual energy comparison? If the grid is able to handle production from a facility w/out storage, wouldn’t it still have an equal total generation to a plant w/ storage?

July 5 at 2:00pmStephen Lacey

My bad. The other plant was PV — I accidentally left that out. I’ve put that in the story for clarification.

July 5 at 2:18pm

Jeff Auxier

I am a big solar advocate. Equating this technology with “Solar can be baseload!” is a stretch.

July 5 at 4:02pm


So 24h delivery is not enough, huh?

July 5 at 5:40pm

Daniel Alós

Gran avance en energía solar!

July 5 at 2:14pm