The tricky art of storing heat from the sun

The poster boy for concentrated solar power with thermal energy storage is Torresol Energy’s 19.9MW Gemasolar power plant in Andalusia, Spain. Photo credit: SENER

The poster boy for concentrated solar power with thermal energy storage is Torresol Energy’s 19.9MW Gemasolar power plant in Andalusia, Spain. Photo credit: SENER

A Chilean renewable energy tender that closed in October could be the first in the world where energy storage becomes the deciding factor for success. Great news for the industry? Perhaps. But actually it’s not so easy to say.

The bidding for a concentrated solar power (CSP) plant in Chile’s Atacama Desert, backed by a USD$20m government grant and more than $86m in alternative funding, is conditional on a minimum three-hour thermal energy storage (TES) facility.

And sources close to the tender, the entries for which are still being considered by the Chilean government, have confirmed that if there is a tie between different offers on all the main eligibility criteria then the amount of storage will determine which project wins. This might sound unusual, but in CSP it’s not something that would raise eyebrows.

After all, CSP players have increasingly been embracing storage in recent years. For those new to the subject, CSP involves focusing sunlight onto a point to create enough heat to drive a turbine. The critical word here is ‘heat’: unlike photovoltaics (PV), CSP does not produce electricity directly from sunlight. That means it can only be used in areas with high solar irradiation. It’s also generally more expensive than PV.
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Storage gets touch of TV glamour

While it has little to do with the industry we couldn’t resist pointing out that a glamorous new ad has an energy storage angle. Mercedes-Benz’s five-minute Sprinter van promotional film is shot in and around Torresol Energy’s Gemasolar concentrated solar power plant in Spain, which readers may know is famous for having the world’s largest molten salt storage reserve.