Utility-Scale Solar

The Sunset of Solel, Siemens and Solar Trough CSP Technology

Siemens, unable to find a buyer for the CSP remnants of Solel, lays off 150 workers.

The Sunset of Solel, Siemens and Solar Trough CSP Technology

The Sunset of Solel, Siemens and Solar Trough CSP Technology

Concentrating solar power (CSP) via solar trough technology is struggling.

In October 2009, German industrial giant Siemens bought solar thermal trough firm Solel for $418 million from founder Avi Brenmiller and other investors.

In October 2012, plummeting PV costs, among other forces, drove Siemens to announce its intention to exit the solar business. It would sell off its solar assets, starting with what was once Solel in Beit Shemesh, Israel. The firm has lost more than $1 billion since 2011, according to Bloomberg.

Last week, Siemens Solar Thermal sent 150 of its 200 employees home, having failed to find a buyer at the right price, according to reports in Globes.

Spain's Abengoa was one of the bidders, but the firm "withdrew its offer because of uncertainty about the market's future, even though Siemens had agreed in principle to finance the plant's operations for two years, 'until the picture clears,'" according to Globes. Founder Brenmiller was also said to be making a bid for his former firm, according to reports. 

At one point, the facility had 400 employees. The firm's remaining employees will support existing Spanish projects, one in operation and three nearing completion.

Solel was one of the early solar thermal players, building hundreds of megawatts of parabolic trough solar thermal plants in California's Mojave desert in the late 1980s and early 1990s. These solar systems use curved reflectors that track the sun and focus sunlight on a receiver tube filled with a fluid that when heated is used to create steam to drive a generator. 

Trough technology would seem to have lost its advantage not only to photovoltaics, but to solar power tower technology, as well. 

No CSP projects were finished in 2012, but at least three projects totaling 750 megawatts are under construction and slated for completion in 2013:

  • Abengoa’s 280-megawatt Solana parabolic trough project in Arizona with six hours of storage and with a PPA from APS
  • The BrightSource Energy (BSE) 370-megawatt (cumulative) Ivanpah Units One, Two, and Three pressurized steam solar power tower in California’s Mojave Desert with a PPA from PG&E and SCE
  • SolarReserve’s 110-megawatt Crescent Dunes solar power tower outside Tonopah, Nevada, with ten hours of molten salt storage with a PPA from NV Energy

Ausra, another trough-based CSP technology company, was founded by Peter Le Lievre and a group of Australians leveraging its compact linear fresnel reflector (CLFR) technology. Areva, the nuclear industry engineering firm, purchased the VC-funded startup in 2010. and its projects include:

  • A 125-megawatt CLFR project in India used as standalone power generation
  • A 44-megawatt CLFR solar augmentation project in Australia (similar to Tucson Electric).
  • A CLFR molten salt storage system on line summer 2013


BrightSource have been rocked by challenges in finance, permitting, personnel, and regulatory domains.

Other CSP firms include eSolar, along with smaller-scale solar modular trough firms such as Suntrough and Sopogy.

With plunging PV prices on one side and historically low natural-gas prices on the other, CSP technology still has its work cut out for it.

from GTM Research 2011 CSP Report

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