Solar Opponents Win: Palen To Be Trough, Not Tower

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According to a filing with the California Energy Commission (CEC) this week, Abengoa has apparently given up on attempting to permit what would have been California’s second concentrated solar power (CSP) project after Ivanpah to use tower technology.

In its latest iteration, this was to have been a 250 MW tower with storage.

Instead, in response to opposition, Abengoa will revert the plan to a trough project.

Image Credit: Brightsource Ivanpah

“In response to the concerns that have been raised, the Project Owner has determined that a solar trough project, similar to that approved in the original application for certification, will be pursued for this site, and the design will include energy storage,” the company said in its filing.

It’s a sad day for California, which had a chance at state-of-the-art advanced technology; tower CSP with storage, thanks to decades of investment in research by NREL and Sandia.

Workers at a
Image Credit: Google

As part of trying to stop Palen, a well-orchestrated media frenzy was created by opponents, centered on the supposed danger to birds at Ivanpah, and claimed 28,000 birds were killed by the project.

This opposition is directly responsible for Abengoa’s dialing back to less advanced technology.

NRG Energy as ⅓ owner was operating Ivanpah when thousands of identical stories made outlandish claims about avian mortality. Many began with this line: “Workers at a state-of-the-art solar plant in the Mojave Desert have a name for birds that fly through the plant’s concentrated rays….”

“Ivanpah is like a lightning rod for news,” former NRG Energy spokesman Jeff Holland confided at the time; astonished by the rancorous coverage. “Everything else is so quiet.”

In April of 2015, the actual first year avian mortality was estimated by HT Harvey (the environmental firm commissioned by the CEC to assess the project) to be at most 3,400, not 28,000.

With no count of the background mortality rate in an equivalent 3,500 acres next to the 3,500 acre Ivanpah site, there is no way to compare this estimate to background mortality rates. The CEC concluded: “Comprehensive Analysis of Ivanpah’s First Year Qualifies Avian Impact as ‘LOW.’ ”

But as soon as Abengoa’s filing appeared, the opponents started up again, on the CEC docket. This time, Abengoa cut short the circus, and after the first five comments on the Palen docket in response to its earlier request to extend the deadline so it could do the engineering design to add storage for the tower project, the firm threw in the towel.

Trough configuration had previously been approved for the Palen site for Solar Millennium, which was bankrupted by the PV price wars in 2011. Abengoa together with BrightSource (as Palen Solar Holdings) bought the permitted site, and had planned to build a 500 MW tower CSP project.

After a long and contentious permitting process, a 250 MW tower with storage appeared to have a way forward, and BrightSource sold its share to the older firm, Abengoa, which has global experience building CSP towers with storage.

Tower is best for storage

Storage is the reason we need CSP. There’s plenty of cheap PV. It does a great job — in the daytime. But to fully replace carbon combustion, we need a solar technology for nighttime too.

Trough is the older technology. Because it uses oil as the heat transfer fluid, it has to sort of “bolt-on” molten salt storage. The hot oil has to go through a heat exchanger to store the heat in tanks of molten salts, ready to boil water to make the steam to drive the turbines when needed.

And since the hot oil is run through miles of pipes out through the solar field, it can’t get to the high temperatures and efficiencies of tower CSP.

Tower is the advanced CSP. It is inherently much more efficient in enabling storage, because the same molten salts circulating up and down the tower can also be stored in tanks for use when needed.

For these reasons, tower — with molten salts — is the obvious choice if you want storage. And California wants storage.

Thank you Jimmy Carter
Image Credit: io9

Instead, the state will now get older trough technology developed in the Carter era, not designed to include energy storage.

The first trough plant, SEGS, was built before storage became a necessity. Its developers were bankrupted by the abrupt repeal of Carter’s advanced energy incentives when the Reagan administration went back to backing fossil fuels.

Like the other nascent solar technology of the time (PV), CSP was then driven from America. While PV went to Japan where Sharp and Panasonic grew to become the first major solar panel makers; CSP went to Spain, and Spanish firms became world leaders in trough CSP.

With generous government support once again advancing clean energy technologies, two California tower CSP developers (SolarReserve and BrightSource), were able to find investors.

BrightSource developed the 377 MW Ivanpah tower CSP in the Mojave desert and SolarReserve is now commissioning Cresent Dunes, the 110 MW tower with 12 hours of molten salt storage at Tonopah.

Despite starting a decade after Spanish CSP, tower bids are now as likely to be awarded to these two US startups globally as to the now well-established Spanish CSP industry.

BrightSource is developing tower projects in Israel and — with storage — in China.

SolarReserve has a 6 GW global pipeline and is developing tower projects with 12 hours of storage in South Africa and with 24 hours of storage at Copiapo in Chile.

But back home in their native California? Just more trough. Thanks, solar zombies.

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