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 [转帖]太阳能：是否一定高技术：Can Desert Solar Supply Europe's Energy? |
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抢注G8
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作者：抢注G8 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
BusinessWeek
Europe May 1, 2008, 1:10PM EST text size: TT
Can Desert Solar Supply Europe's Energy?
The technology already exists to harvest the sun's power in North Africa and the Middle East for use in the north. All that's needed is investment
by Jens Lubbadeh
The oil of the 21st century is not buried deep within the earth. Instead, it falls on its surface—as sunshine.
"The sun is the hidden asset of North Africa and the Middle East," says Gerhard Knies, a spokesman for the Trans-Mediterranean Renewable Energy Cooperation (TREC), a network of scientists and politicians from various countries who have taken it upon themselves to solve Europe's energy problem.
Their vision, which they call Desertec, is to turn desert sun into electricity, thereby harnessing inexhaustible, clean and affordable energy.
"We don't have an energy problem," says Hans Müller-Steinhagen, of the German Aerospace Center (DLR). "We have an energy conversion and distribution problem."
Müller-Steinhagen has been commissioned by Germany's Environment Ministry to check the feasibility of Desertec in several studies. His conclusion is that Desertec is a real possibility.
In his studies, he has scrutinized the energy situation in Europe, North Africa and the Middle East from the point of view of the post-oil era. Out of all the alternative energy sources, one stands head and shoulders above the rest: "No energy source even comes close to achieving the same massive energy density as sunshine," Müller-Steinhagen says.
And no other energy source is available over such a large area. Every year, 630,000 terawatt hours in the form of solar energy falls unused on the deserts of the so-called MENA states of the Middle East and North Africa.
In contrast, Europe consumes just 4,000 terawatt hours of energy a year—a mere 0.6 percent of the unused solar energy falling in the desert.
Powering Europe from the Desert
Europe needs a lot of electricity, but gets little sun. The MENA countries, on the other hand, get a lot of sun, but consume little electricity. So, the solution is simple: The south produces electricity for the north. But how would the enormous energy transfer work? And how do you turn desert sun into electricity?
It's actually relatively easy. Desertec is low-tech—no expensive nuclear fusion reactors, no CO2-emitting coal power plants, no ultra-thin solar cells. The principle behind it is familiar to every child who has ever burnt a hole in a sheet of paper with a magnifying glass. Curved mirrors known as "parabolic trough collectors" collect sunlight. The energy is used to heat water, generating steam which then drives turbines and generates electricity. That, in a nutshell, is how a solar thermal power plant works.
Energy can be harnessed even at night: Excess heat produced during the day can be stored for several hours in tanks of molten salt. This way the turbines can produce electricity even when the sun is not shining.
Should the Sahara, therefore, be completely covered with mirrors? No, says Müller-Steinhagen, producing a picture by way of an answer. It shows a huge desert in which are drawn three red squares. One square, roughly the size of Austria, is labelled "world." "If this area was covered in parabolic trough power plants, enough energy would be produced to satisfy world demand," he says.
A second square, just a fourth of the size of the first one, is labelled "EU 25," in a reference to the 25 member states the European Union had before Bulgaria and Romania joined in 2007. This area could produce enough solar energy to free Europe from dependence on oil, gas and coal. The third area is labelled "D," for Germany. It is merely a small dot.
A Win-Win Situation
Under the plan, the sun-rich states of North Africa and the Middle East would build mirror power plants in the desert and generate electricity. As a side benefit, they could use residual heat to power seawater desalination plants, which would provide drinking water in large quantities for the arid countries. At the same time they would obtain a valuable export product: environmentally friendly electricity.
"The MENA countries are in a three-way win situation," says Müller-Steinhagen. But Europe also wins: it frees itself from its dependence on Russian gas, rising oil prices, radioactive waste and CO2-spewing coal power plants.
For countries such as Libya, Morocco, Algeria, Sudan and especially Middle Eastern states, the solar power business could be the start of a truly sunny future. It could create jobs and build up a sustainable energy industry, which would bring money into these countries and enable investment in infrastructure.
In fact, Desertec is no futuristic vision—the technology already exists and is tried and tested. Since the mid 1980s, solar thermal power plants have been operating trouble-free in the US states of California and Nevada. More plants are currently being built in southern Spain. And building work has started on solar thermal power plants in Algeria, Morocco and the United Arab Emirates.
Part 2: Making the Switch
Müller-Steinhagen has calculated what the energy switch would cost: To generate 15 percent of Europe's electricity demand, around €400 billion ($623 billion) would be needed by 2050 to pay for the construction of solar thermal power plants. The power plants would cost €350 billion, while €50 billion would have to be spent on an electricity grid network to transport electricity from North Africa to Europe.
This would require a network of high-voltage direct current transmission lines—also a technology which exists and is tried and tested. It is the only way to transport electricity for thousands of kilometers with relatively little energy loss.
But if it is all so simple, then why do countries with enough solar radiation build expensive and dangerous nuclear power plants, instead of investing in this simple technology? Are there not deserts in the US? Why are Americans not freeing themselves from their oil dependence through solar power? And why has no one really started to exploit the technology?
"After the solar thermal power plants were built in California and Nevada, people lost interest in solar thermal power because fossil fuels became unbeatably cheap," says Müller-Steinhagen. Solar power was neglected even though the US was in the advantageous position, compared to the MENA region, of being a single political entity rather than a conglomerate of countries with differing interests. The US could achieve energy self-sufficiency through solar thermal power plants in the sunny south-west. But it was only recently that scientists writing in the respected magazine Scientific American unveiled a "Solar Grand Plan" for the US.
Cheap oil has stood in the way of a solar thermal breakthrough. Although sunshine abounds in Saudi Arabia, the United Arab Emirates, Kuwait and other countries, so does oil. However these rich countries could also afford to build solar thermal power plants. "In Saudi Arabia or the United Arab Emirates, electricity costs half a cent per kilowatt hour," Müller-Steinhagen says. "This makes it hard to convince people of the benefits of solar thermal power."
Lack of Awareness
"There is a lack of awareness in MENA countries about what this technology can do," says Samer Zureikat, founder of the Frankfurt-based renewable energy company MENA Cleantech. "If you talk to people there about solar power, they think of small solar panels that power street lamps. They don't think of enormous power plants that can supply enough electricity for a whole country."
For Zureikat, the switch to solar thermal energy is an inescapable necessity: "Europe needs energy. North Africa and the Middle East need water—and fast."
Müller-Steinhagen agrees with him. In a different study, he investigated the region's future need for water and the possibility of desalinating sea water with solar thermal-produced energy. The study's conclusion was that water shortages in the MENA region would triple by 2050.
The interest in solar thermal power is slowly growing. Masdar, an Abu Dhabi-based firm which invests in alternative energy, is a partner in a project constructing three solar thermal power plants in Spain. It also wants to build them in its own country.
Admittedly, solar thermal-produced power is still not competitive. However, conventionally generated energy is getting more and more expensive—and solar thermal power gets cheaper with the construction of every new power plant. By 2020 at the latest, Müller-Steinhagen predicts, solar-thermal electricity will be the same price as fossil fuel-generated energy. On top of that, solar thermal has greater price stability as the sun yields unlimited and free energy, which does not require elaborate and costly raw material extraction.
Solar Sarko
Müller-Steinhagen wants people to take another look at the technology—and quickly. Now is the right time, he says: Europe's old power plants are coming to the end of their operational lives and new ones have to be built. These investments will decide the future of our power, given that the operational lives of power plants extend into decades.
And politicians are starting to take an interest in the idea. The German government is supporting it. On the European level, German members of the European Parliament such as the Green Party's Rebecca Harms and Matthias Groote from the center-left Social Democratic Party are throwing their weight behind Desertec.
Even French President Nicolas Sarkozy has also suddenly discovered solar energy, despite his recent sales of nuclear power plants to North African states. "We are being inundated with enquiries from France," says Müller-Steinhagen. Sarkozy wants to promote solar energy within his controversial Union for the Mediterranean, a proposal for a loose alliance of countries bordering the Mediterranean Sea and other EU states.
SPD politician Groote is hoping for "new initiatives when France takes over the EU presidency in the second half of the year." However, his Green Party colleague Harms warns against too much optimism: "There is still only a minority in the European Parliament promoting solar thermal power. We are still a long way from a unified energy policy."
Too many questions remain unanswered. Who will pay for the electricity network? Who would own it? Could the various stakeholders agree on a collective guaranteed price for solar thermal electricity fed into the grid?
The latter issue is especially important for investors and industry. Wolfgang Knothe, a board member of MAN Ferrostaal, an industrial services provider, says: "We need political security to get going."
A lack of money is not the problem. "Renewable energy is in," says Nikolai Ulrich of HSH Nordbank. "It is relatively easy at the moment to get investment for renewable energy projects."
Desertec is still only a vision. But visions are needed, says Knothe: "Without Kennedy's dream, there wouldn't have been a moon landing."
Then, the will to make the vision reality existed, although the technology did not. With Desertec, it is exactly the reverse: The technology is available—but the will is missing.
作者：抢注G8 在 海归商务 发贴, 来自【海归网】 http://www.haiguinet.com
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 [转帖]太阳能：是否一定高技术：Can Desert Solar Supply Europe's Energy? -- 抢注G8 - (11589 Byte) 2008-6-25 周三, 07:12 (1020 reads)
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