Sun, Jun 26, 2016 page14

• In Israeli desert, world’s highest solar tower looks to future

  Part of Israel’s plan to make renewable energy account for 10 percent of its power supply by 2020, the Ashalim solar tower faces criticism of being too expensive and complex

  • By Daphne Rousseau / AFP, ASHALIM, Israel
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  In the middle of southern Israel’s desert, engineers are hard at work building the world’s tallest solar tower, reflecting the nation’s high hopes for renewable energy.

  Once completed late next year, the Ashalim Tower will rise to 240m, taller than Paris’ Montparnasse Tower and London’s Gherkin, according to the Israeli government and the consortium building it.

  Covered in stainless steel, the square tower in the rocky Negev Desert with a peak resembling a giant lighthouse will be visible from dozens of kilometers away.

  

  A picture taken on May 26 shows some of the 55,000 mirrors directing sunlight toward the Ashalim solar tower that is under construction near the southern Israeli kibbutz of Ashalim in the Negev Desert.

  Photo: AFP

  A field of mirrors covering 300 hectares — the size of more than 400 football pitches — will stretch out from its base, directing sunlight toward the tower’s peak to an area called the boiler, which looks like a giant lightbulb.

  The boiler, whose temperature will rise to 600°C, generates steam that is channeled towards the foot of the tower, where electricity is produced.

  The construction, costing an estimated 650 million euros (US$723 million), is being financed by US firm General Electric, which has bought the energy business of France’s Alstom, with Israeli private investment fund Noy also involved.

  Israel’s government launched a tender for the project in 2010, committing to purchase electricity from it over 25 years as part of a shift toward renewable energy and energy independence.

  The country mainly generates electricity using plants fired by coal, natural gas and fuel oil. Its domestic supply of natural gas has grown with the discovery of fields in the Mediterranean.

  Solar requires a major investment, though costs are gradually coming down.

  Energy from a solar tower is “two to three times more expensive to produce than classic electricity plants using carbon,” for example, said Eran Gartner, who heads the Megalim consortium managing the project.

  The tower should provide 121 megawatts, or 1 percent of Israel’s electricity needs, enough for a city of 120,000 households.

  The nation of 8 million people is seeking to make renewable energy account for 10 percent of its total consumption by 2020.

  Solar power offers a clean alternative to fuel and carbon-fired electricity plants, which contribute to global warming with their heat-trapping carbon dioxide emissions.

  “The government agreed to move ahead with this technology — even though we do not hide the fact that it is more expensive than traditional electricity production — precisely to achieve lower costs over time,” Gartner said at the site.

  “The second solar tower will be slightly less expensive, the third much less expensive, et cetera,” he said.

  He predicted a futuristic landscape of towers overlooking the desert.

  Israel could in theory meet all its electricity needs through solar energy by using only 4 percent of the Negev Desert, said Eitan Parnass, head of the Green Energy Association of Israel.

  Israel’s offshore gas finds are a major boost toward energy independence, but Parnass said it must continue to diversify to avoid reliance on a single source in the turbulent Middle East.

  “We are in a situation where we cannot simply look at the economic aspect,” he said.

  “Israel has no choice but to diversify its energy independence, first for reasons of security,” he said.

  However, critics have panned the project as too expensive and complex compared with other solutions.

  Yael Cohen, an Israeli lawmaker with the opposition Zionist Union alliance and co-chair of the Green Movement political party, said the project has “requirements so demanding and costs so high” that it cannot be replicated.

  Solar power has for years formed a part of life in Israel, where rooftop panels are often used to heat the water tanks of homes.

  A solar tower and its field of mirrors, a technology known as concentrated solar thermal, is only profitable as part of a large-scale project, unlike a photovoltaic field, where each panel acts as a small generator.

  The Ashalim Tower will be equipped with 50,600 projecting mirrors, amounting to a total reflective surface of 1 million square meters.

  Like sunflowers, the mirrors will turn toward the path of the sun.

  Engineers have developed reservoirs for the task of storing heat when the sun is not out.

  “It’s the big plus of solar tower technology ... centralization and stockage of energy at nighttime opens the path to massive use of solar electricity in Israel,” Parnass said.

  Solar towers have already been built in locations such as Morocco, South Africa and California, where the world’s tallest at present — standing at 137m — is in Ivanpah in the Mojave Desert.

  “We multiplied the size of the mirrors by a third compared to the previous generation,” Gartner said. “Everything is connected by WiFi instead of by cables. The tower and its boiler are also designed to reduce costs. Everything is done to pursue profitability.”
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