Eskom’s latest CSP RFI is as much about storing energy as it is about generating it.
By Tom Nevin in Cape Town
Soon after its leap of faith into the fledgling concentrated solar power (CSP) community, South Africa appears keen to extend its membership in the small but growing club of innovative solar energy generation. Eskom, South Africa’s state-owned power utility, has issued a request for information that tests market interest for the design, supply and installation of a 100MW CSP plant planned for Upington in the sunny Northern Cape Province. Completion date is 2016.
After a flurry of initial interest, South African CSP assumed Cinderella status when it attracted little further attention - due mainly to commercial bank reluctance to fund what they considered to be an untested and risky energy generation method, despite successful projects in the US and Spain.
This changed in March this year, when a partnership comprising Spanish CSP pioneer Abengoa, and the South African Industrial Development Corporation won a bid to develop a two-pronged 150MW CSP venture in the region. This includes a 100MW parabolic mirrors solar plant at the embryonic Uppington solar park and a 50MW tower installation near the hamlet of Pofadder, 100km to the west.
Both projects will sell their output to Eskom. The 100MW CSP plant could well be the first energy producer in the park when it switches on in June 2014.
Expressions of interest for Eskom’s latest RFI are anticipated from both South African and foreign contenders and the response should be interesting. A CSP tower project with storage capacity backed by Eskom, coud see financial risk virtually disappear and tendering could be brisk.
The development of the heat-storage capabilities of CSP has generated an undercurrent of speculation over whether this is of more than passing interest to Eskom. CSP technology trumps most other electricity generating systems with its storage capacity.
Although not yet at jackpot status, CSP tower can incorporate molten salt as a storage and heat transfer medium, a strong basis for the technology to take pole position in future proliferation that could sooner rather than later assume fleet proportions.
“A CSP tower system’s ability to store six hours of heat is enough at this early stage of development to be attractive to the industry. The process efficiently collects energy until mid afternoon when solar radiation begins to drop off and delivers it at the time of peak demand until around 9pm when demand drops”, explains Ken Robinson, senior executive at management consultants Accenture.
Heat storage is undoubtedly the Holy Grail in contemporary energy and the Upington solar park’s ultimate success could well depend on the level of heat storage innovation that can be achieved.
This spark of anticipation has prompted Eskom to call for CSP heat storage information to be included in its latest RFI. Specifically, it calls for “a 100MW central receiver concentrated solar power plant (with molten salt as storage and heat transfer medium)”.
The utility also intends to contract with an “owner’s engineer” to assist it initially with the business case, basic engineering and with preparation of bidding documentation. This entity would also be expected to act as an execution partner.
Base load contender
A growing number of analysts maintain that Eskom’s interest in CSP confirms its belief that CSP has the potential to deliver base load power, the current preserve of fossil fuel, nuclear and hydro.
Hydro is an questionable prospect for much of Africa. Water sufficient for big dam purposes occurs in only equatorial regions, about 20% of the land mass, whereas solar radiation is abundant, partcularly in the southwestern and northern parts of the continent.
The Northern Cape area selected for South Africa’s CSP baptism is notable for the amount of sunshine that radiates onto virtually 365 days a year. South Africa's DNI easily tops 2,900 kWh/m2/year. The best possible in the US southwest, for comparison, ranges from 1300kWh/m2/year (in Daggett, CA) to 2,700 kWh/m2/year (in Arcata, SF).
Funding for the project will most likely come from the World Bank and the Clean Technology Fund, along with such institutional lenders as the African Development Bank. Commercial banks could also show renewed interest. Potential suppliers and contractors had until May 8 2012 to register their interest.
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*Article updated 11.05.12