Autor: David Tscholl , 07.04.2013

Since the 90s the South American country of Chile has seen a rapid economic development. This growth is accompanied by a growing energy demand, which currently increases at an annual rate of eight percent.

According to Chilean President Sebastian Pinera it will take an expansion of the country's installed hydropower output from currently 17 GW to 25 GW to satisfy the growing energy demand until 2020. Chile's energy matrix shows that about 60 percent of the country's demand is covered by fossil fuels, of which almost the entire supply has to be imported. The remaining 40 percent of demand is met by renewable energy sources. Hydropower accounts for about 35 percent, and therefore the lion's share, making it the most important source of electricity produced from the country's own resources.

In 2004 Chile had to deal with problems caused by its growing dependence on energy imports when gas deliveries from Argentina stopped and the country experienced a shortage in its electricity supply. This situation resulted in a new energy policy focusing more strongly on energy efficiency and renewable energy sources.

In recent years large hydropower projects have faced growing resistance from environmental protection activists. In 2004 the Chilean government provided support even for small hydropower projects with a new legislation: the laws “Ley Corta 1” and “Ley Corta 2” support and facilitate a profitable operation of small hydropower plants. Thanks to these legal simplifications and facilitations a small but interesting hydropower plant project was realized near the city of Cunco in the Araucanía Region last year. Bavarian turbine manufacturer Ossberger provided its renowned cross-flow turbines including the clever SCADA control system.

The new hydropower plant was constructed on a 5 km long irrigation channel, which deducts a water volume of 18 m3/s from the Río Allipén. Depending on the season the river carries a water volume of 100 m3/s up to 1,000 m3/s. During the summer months the water of the channel is used to irrigate agricultural fields, while during the winter months the water is not needed by farmers. During this period or in longer rainy seasons the water of the channel is used to produce hydropower energy. The head at the end of the about 5 km long diversion channel measures 20 meters.

For the construction of the small hydropower plant a joint venture was founded by the Allipén irrigators collective, a collective of local farmers and operators of irrigation plants, and the Santiago de Chile–based company GPE (Gestión de Proyectos Eléctricos). The company specializes in developing and operating small power plants together with agricultural associations, such as the hydropower projects Huasco in Vallenar and Puclaro in La Serena, both positioned at the bottom of irrigation storage reservoirs, as well as the Mallarauco power plant, which was also built next to an irrigation channel. In general these projects bear more advantages for the Chilean agriculture than just supporting more than 120,000 farmers, who would not be able to realize such plants considering their low income. The farmers can still use the water at their disposal, they can make additional profit with the hydropower plant and they can, at least partly, invest in improvements of their existing irrigation systems. At the same time the local electrical grid is improved with the construction works of the plant. Chile has an extraordinarily great potential for such hydropower plants. Unfortunately there are huge differences of opinion within the irrigator collectives regarding these projects: 5060 members of the Puclaro collective had negotiated for more than three years until an agreement for the construction of the small hydropower plant was reached.

Regarding the selection of a suitable turbine type the Chilean company GPE relied on the tried and tested cross-flow turbines manufactured by Ossberger. The operator saw the advantages of the cross-flow turbines by Ossberger in the small effort needed for the installation, the easy handling and easy maintenance as well as the turbines' good part load behavior. For the channel's total flow rate of 18.0 m3/s two cross flow turbines identical in construction were installed, which produce a nominal output of 1.48 MW each at a head of about 20 meters. The two synchronous generators manufactured by AEM Dessau have an output of 1.48 MVA each. For this plant Ossberger also delivered a SCADA system automatically controlling the two turbines. It enables monitoring and controlling not only on site but also over the internet with access being protected by passwords and authorization regulations.

The construction works on the hydropower plant near Cunco on the Chilean Río Allipén took about one year. The plant was put into operation in May 2012 and has been running smoothly ever since, very much to the operators' satisfaction. In general there are a few adjustments and improvements to be made throughout Chile in order to increase the efficiency of the country's existing hydropower potential. GPE, a specialist for small power plants, relies on the technical know-how of its experienced European partners to promote the development of hydropower in the South American state of Chile with flagship projects, such as the power plant on the Allipén River.

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