Spain’s concentrated solar power association has handed lawmakers a study claiming the technology could help achieve an 85 percent renewable grid by 2030. 

The model, developed by the industry body Protermosolar, also forecasts the complete elimination of coal and nuclear from the electricity system, with a 92 percent cut in carbon emissions and costs more or less the same as at present.

Protermosolar developed the model, using consumption data from 2014 to 2017, in response to a government-commissioned report issued earlier this year on how to meet 296 terawatt-hours of electricity demand a year by 2030.

The report predicted Spain would need to keep its coal and nuclear capacity and build out almost 24.6 gigawatts of combined-cycle gas generation to serve as backup to around 47 gigawatts of solar PV, or about 10 times the amount installed in the country today.

The expert commission’s model would cut carbon dioxide-equivalent emissions by around 81 percent from 2017 levels. But it would miss the recently approved European Union target of a 32 percent renewable contribution to total energy consumption. 

It would also see 4.6 terawatt-hours of renewable energy per year being curtailed. In contrast, Protermosolar’s plan would meet the European Union target while curtailing just 830 gigawatt-hours a year.

The secret to Protermosolar’s scheme is to cap the PV build-out at 25 gigawatts, or a little over half of that envisioned by the expert commission, and to add 17.7 gigawatts of concentrated solar power to Spain’s existing fleet of 2.3 gigawatts.

Protermosolar imagines that all the new CSP capacity would be equipped with around 15 hours of thermal storage, and the plants would be used exclusively to store energy during the daytime and feed it back to the grid at night. 

This would allow CSP to complement diurnal PV production over and above the output from 33 gigawatts of wind, up from 23 gigawatts today.

Protermosolar’s analysis of historical data showed wind output was a fairly steady 25 percent of total installed capacity across the country.

The association’s proposed mix would also help guard against a massive duck curve associated with an excessively PV-heavy grid.

Around 23 gigawatts of hydro and pumped hydro, 15.8 gigawatts of combined-cycle gas, 8.5 gigawatts of cogeneration and 5 gigawatts of biomass and biogas, along with energy imports from Europe, would help the electricity system deal with any wind and solar shortfalls.

In building its model, Protermosolar assumed “reasonable” improvements in mainstream renewable technologies. One of these enhancements was in the average cost of CSP, which was estimated as being €55 (USD $64) per megawatt-hour. 

This is significantly below the estimate provided by Lazard in its latest levelized cost of energy analysis, issued last November. Lazard calculated a price range of between $98 and $181 per megawatt-hour for solar thermal towers with storage.

But Protermosolar’s president, Dr. Luis Crespo Rodríguez, told GTM that his association’s estimate was not unreasonable given that a project being developed by ACWA Power in Dubai was given a tariff of $73 per megawatt-hour last September.

Dubai and southern Spain have similar levels of direct normal irradiance, he said, adding, “We think that with a 17-gigawatt market in Spain, having a price of €55 is not excessive.”

Previous energy mix models, including the expert commission’s study, ignored CSP as a viable generation source. Crespo Rodríguez said they used outmoded data on the technology’s cost and efficiency.

The 14-member expert commission was not expected to promote CSP.

Hand-picked by a government known for its anti-renewables stance, the commission had practically no research budget and worked on its 550-page study while juggling other duties, according to Crespo Rodríguez. Now things have changed, though.

In June, a new, pro-renewables administration took the reins in Spain and the energy portfolio was handed to a former boss of Abengoa, one of the world’s leading CSP players.

Does this mean the country might consider betting its energy future on a technology that is still struggling to prove its worth? Crespo Rodríguez said Protermosolar is still awaiting a response to its study from Spain’s newly minted Ministry for Ecological Transition.

“I’m convinced that when they see it, this will open their eyes,” he said. “It shows we can advance more rapidly.”