Five hybrid energy farms

Five new hybrid windfarms on as many islands in the Aegean Sea are about to be built by the Public Power Corporation (PPC) to meet demands for electricity supplies. It is a «smart» technology, combining the use of different sources of energy, and has successfully been introduced on the island of Kythnos in recent years. The State has now turned its attention to renewable sources of energy because time is running out for Greece to fulfill its commitments to the European Union and the Kyoto Protocol. Hybrid energy farms are the first step toward broader use of renewable energy sources, combining wind, solar and/or hydroelectric energy with existing power plants using mineral fuels or petroleum. Renewable sources of energy will be used to complement conventional forms when the natural elements are uncooperative (such as on windless or cloudy days). «Hybrid systems are most beneficial as they give priority to renewable energy sources. If conventional means remain our main source of power, the gains will be very small,» Machi Sideridou, in charge of the campaign on climatic change for Greenpeace, told Kathimerini. Greece is committed to promoting renewable energy sources since it signed the Kyoto Protocol. In addition, a European Union directive rules that by 2010, 20.1 percent of energy must be produced from renewable sources. «At the moment, of the 11,000 megawatts (MW) required in Greece, just 270 MW come from renewable sources. So we need another 2,500 MW from renewable sources within the next eight years. So we have to move fast. And as photovoltaic technology is not yet developed enough, windfarms are attracting the attention of more and more investors,» Sideridou said. PPC began its first research in the early 1990s, but Sideridou said that experience has shown that it did not do as much as it could. Today, things have changed. «There should be an increase in the use of renewable energy sources at autonomous and weak networks, such as on the islands,» said Nikos Stavridis, director of PPC’s department of renewable energy sources. «So our studies are focusing on the way the use of natural sources such as wind, sun and water can be combined with diesel engines to save energy. The Kythnos model is considered one of the most successful of its kind around the world,» he added. Kythnos has the country’s only hybrid system. It began in 1982, within the framework of a European program to develop soft forms of energy. Five wind generators (each 25 kilowatts) were installed. In 1983, a 100 kW photovoltaic farm was set up (the second in Greece) which works independently in combination with the wind and diesel generators. The system operated on a trial basis until 1990, when some changes were made to the photovoltaic park and the five wind generators were replaced with new technology models (35 kW). In 1999-2000, a new powerful wind generator was installed on Kythnos, with a capacity of 500 kW and the country’s first truly hybrid system, one based on a combination of solar and wind energy. Soft forms of energy can now cover the island’s energy consumption needs, when conditions are favorable. «The results of the Kythnos farm’s operation are very good, but not as good as we would like. The use of alternative energy sources is greater than on other islands such as Icaria and Lemnos, but for reasons to do with the network, it is usually at about 20 percent,» said Stavridis. «Under certain conditions of course, it reaches 100 percent, doing away with the diesel generators. But the hybrid parks require high technology and delicate handling. The greatest disadvantage is their operation, as they require specialized scientific staff who do not always find it easy to get to these islands.» Icaria, Sifnos, Serifos, Astypalaia, Gavdos The cost of producing electrical power varies from one area to another, although PPC, for reasons of social policy, has just one billing system, a situation that the use of alternative energy sources could help solve. «For example, on Crete, the cost of operating windfarms is 2 drachmas/kW (2,000 drachmas or 5.87 euros/1,000 kW), compared to 40-76 drachmas/kW (0.12-0.22 euro) for petroleum-operated power stations. It costs PPC 70 billion drachmas (205 million euros) annually to operate petroleum-powered stations on the Aegean islands,» said Stavridis. So five new hybrid farms are to be set up on the islands of Icaria, Sifnos, Serifos, Astypalaia and Gavdos. On Icaria, an existing windfarm has seven, extremely productive generators (each 55 kW). Soon, generators more powerful than those on Kythnos are to be installed with a total capacity of 2 MW. Studies are under way to see how an Agriculture Ministry dam can be used to build a small hydroelectric unit. The farm has been included in the third Community Support Framework (CSFIII) and is due for completion within the coming year. Windfarm construction on the islands of Sifnos, Serifos and Astypalaia has been included in the CSFIII. Greek and foreign experts are researching it. PPC is seeking extra funds for the hybrid system, so that the windfarms can be combined with diesel engines. On Sifnos, the use of the existing photovoltaic farm (60 kW) is being considered. On the islet of Gavdos, south of Crete, there is already a small photovoltaic farm (24 kW) and an effort was made to include a second, 100 kW farm combined in a single system with two diesel engines, in the second CSF. However, PPC did not meet the deadline because of a dispute with a local landowner. Specifications for the plan are to be altered to attract more investors, and funds will be sought from CSFIII.

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