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dam-l Solar station in Cape Town/LS
The following appeared in the Nov. 5 "Cape Times" from South Africa.
>
>THE global energy debate has been renewed as the Green Party in Germany is
>pushing for the abolition of nuclear power early in the next century. South
>Africa, with its abundant sunshine, could lead the way if the Northern Cape
>government guilds a power-generating solar chimney in its desert region.
>Environment Writer MELANIE GOSLING reports.
>
>THE Northern Cape government is chasing international backing for a
>revolutionary solar-powered power station that would be one and a half
>times as high as Table Mountain - and three and a half times taller than
>the highest building in the world.
>The power station, which is planned to be built in the Northern Cape desert
>at a cost of R2-bn, will be up and running in about five years time.
>The station will generate about 200 megawatts of power, about twice as much
>as the "pocket nuke" power stations that Eskom plans to build in South
>Africa.
>In addition to the chimney, the power station will have a circular glass
>"roof" near the base of the chimeny about four kilometre in diameter.
>The Northern Cape government appointed a consultant, Wolf Stinnes, to do a
>pre-feasibility study on the solar power station, and based on his results,
>have given him the go-ahead to do a full feasibility study.
>Stinnes will work with the University of Stellenbosch's department of
>mechanical engineering on the project, led by Professor Detlev Kröger.
>The Northern Cape government plans to raise international funding to
>finance the project.
>Dr Thomas Harms of the university's thermodynamics division, who will also
>be working on the project, said it would be possible to raise international
>funding.
>"The tower is designed by a Germany civil engineering company,
>Schlaich-Bergermann and Partners, who are confident that they can guarantee
>the structure, and at the university our new studies can guarantee that the
>thermodynamics will work.
>"With those two guarantees, international funding can be raised.
>"Also, internationally there is a need to look at alternative energy
>sources. There are several reasons for this. One is that fossil fuels are a
>finite resource and therefore have a limited lifespan, and another is the
>resistence to nuclear power. The Green Party in Germany now wants to
>decommission nuclear power plants.
>"But probably the most important is the scientific view regarding the
>effects of carbon dioxide emmissions, which result from burning coal and
>oil, a greenhouse gas which contributes to global warming.
>"Solar energy has no carbon dioxide emissions. These factors mean there is
>international interest in getting a full-sized solar plant up and running,"
>Harms said.
>One solar power station, designed by Schlaich Bergermann and Partners, has
>been operating in Spain in Manzanares, 150km south of Madrid, since 1982.
>It was built as a research station to test the efficacy of solar power. It
>was relatively small with a chimney of only 195m high, and could generate
>only 50kW (subs: kilowats, NOT to be confused with megawats MW).
>The aim of the Spanish power station was to verify the performance of the
>solar power design. So successful was the research project, that the
>designers, Schlaich Bergermann, put out a booklet distributed to various
>countries saying: "What is there to stop us doing it now?"
>They say that although the construction costs are high, the running costs
>are extremely low. The solar power station in Spain operated with only two
>people, so staff costs are low compared with nuclear or coal-fired power
>stations.
>Also, unlike conventional power stations, solar power stations do not have
>to buy fuel or pay for the disposal of waste. The sun's energy is free, and
>leaves no waste to clean up.
>Says Harms: "Virtually all the cost of the solar plant is in the
>construction. It runs very cheaply with only a few operators, compared to
>hundreds in coal or nuclear power stations.
>"According to calculations by Stinnes, it will be cheaper than coal-fired
>power stations in the long run, one of the reasons is because it has a very
>long lifespan - about 100 years, compared to about 50 years for a
>coal-fired power station."
>The solar power energy station consists of a long chimney with wind
>turbines inside, and surrounded by an enormous horizontal glass structure
>about 6m off the ground.
>The glass roof "collects" the sun's radiation. Rather like a garden
>greenhouse, the shortwave radiation penetrates the glass and traps the
>longwave radiation from the heated ground. The ground under the glass roof
>heats up and transfers its heat to the air above it. This hot air rises and
>flows up the chimney, and this air current drives the turbines in the
>chimney.
>The South African solar power station will have a chimeny 1500m high and
>160m in diametre. The glass roof around the base of the chimney will be
>four kilometres in diametre.
>Rodney Buttle, who heads Eskom's renewable energy research division, says
>they have reservations about the "very ambitious" project.
>Originally Eskom was working jointly with the University of Stellenbosh and
>the Northern Cape government on the project.
>"Eskom is still evaluating four types of solar power, one of which is the
>chimney. At this stage we don't believe we're in a position to elect one of
>the four technologies above the others.
>"But the others have run ahead with the chimney technology. We're still
>particpating in the sense that we're sharing knowledge, but we believe
>their project is very ambitious and has a lot of questions which remain
>unanswered.
>"Eskom's not opposing it, but they've run ahead of the game and made
>certain assumptions. The scheme has the potential of not meeting
>expectations," Buttle said.
>Stinnes says Eskom was meant to do the pre-feasibility study, but because
>they dragged their feet, the Northern Cape appointed him instead.
>"Eskom's chairman has said there is no future for solar power generation in
>South African, yet this is one of the fastest growing areas of power
>technology in the world. This design will be a world first because it will
>be able to generate power 24 hours.
>"We're still hpayy for Eskom to come on board, but theyu've got a lot of
>catching up to do," Stinnes said.
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Lori Pottinger, Director, Southern Africa Program,
and Editor, World Rivers Review
International Rivers Network
1847 Berkeley Way, Berkeley, California 94703, USA
Tel. (510) 848 1155 Fax (510) 848 1008
http://www.irn.org
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