STORING SUN IN STEAM

Direct steam generation: Full steam ahead for grid parity
Eric Jaques, 11 June 2010 (CSP Today)

"…[T]he synthetic oil…coursing through the world’s concentrated solar power (CSP) plants’ absorber tubes…[is flammable] and toxic..[and] hampering the technology’s mainstream prospects, breaking apart at 400° Celsius and effectively imposing a temperature limit on solar installations.

"With sheer cost curtailing CSP’s utilitarian evolution, many experts are eyeing direct steam generation (DSG)…No heat exchange systems, no oil costs, and the removal of several thermodynamically compromising steam production steps means solar field investment costs could be cut by around 15 percent…What’s more higher temperatures will result in greater power cycle efficiencies and lower fluid pumping parasitics."

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"Power towers such as PS10 and PS20 already produce direct saturated steam at around 250°C, but the key superheated technological battle is likely to be waged between parabolic trough and linear Fresnel, both of which are starting to dream beyond the pilot plant realm…

"Leading the way for parabolic trough is the Spanish consortium of CIEMAT, IDEA, and Iberdrola, which is aiming to build a 3 MW plant in the municipality of Puertollano, Spain, by 2012. Last year the project stalled due to lack of public funding, but the green light is back on after consortium members agreed to foot the bill."

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"As for Fresnel, Ausra, a major player owned by French nuclear giant Areva, was recently selected as the solar steam boiler supplier for the proposed 100 MW JOAN1 concentrated solar thermal power project in Ma’an, Jordan…The project is expected to go live in 2013 as the largest DSG CSP project in the world…

"…Solar Power Group, which unveiled the first large-scale pilot plant in 2000 and has long since gained first-mover advantage in the 450°C space…is currently developing four new projects…[and may] hit the market with approximately 15% cheaper electricity costs than equivalent parabolic trough systems…"