Small hydropower has a bigger future in Europe

Hydroelectricity already generates almost 20% of the world’s electricity.

As well as being renewable, it is competitive with other energy sources and far more reliable than wind, solar or wave power. Despite its advantages, however, it does not represent a quick fix solution to the current energy dilemma and can cause significant problems.

The Bakun dam in Malaysia is supposed to be completed in February next year. First proposed in the 1960s, it will be the second highest rockfill dam in the world and will flood an area of 700 square kilometers, equivalent to Singapore. It has been dogged with social and environmental controversies: Sarawak indigenous people have been relocated and tropical rainforest is being destroyed.

Hydroelectric projects upset ecosystems. The water which flows out of the dam differs in temperature and silt content to the water upstream. It can cause bank erosion and endanger plant and animal life. In North America, wild salmon populations have been affected because dams have cut off their upstream spawning grounds.

Despite its green image, hydroelectricity can be responsible for greenhouse gas emissions in countries with tropical climates. When the vegetation around and at the bottom of reservoirs begins to rot it produces carbon and methane. A study conducted by Philip Fearnside of Brazil’s National Institute for Research in the Amazon in Manaus, estimated that, in 1990, the Curuá-Una dam in Pará, Brazil, contributed to the greenhouse effect three-and-a-half times more than generating the same amount of electricity from oil would have done. These concerns are of less importance in colder countries where the climate is less conducive to producing greenhouse gases.

For the EU the sites for large-scale hydroelectric dams are all but exhausted. The EU is now focusing on the development of small hydropower (SHP), which already has an installed capacity of 11,600 MW. SHP installations typically have capacities which are lower than 10 MW and place an emphasis on environmental integration. Although the sites required are smaller, success still depends on a country’s geography. Almost 85% of Europe’s capacity is located in six countries. Italy is the leader (2,405.5 MW), followed by France (2,060 MW), Spain (1,788 MW), Germany (1,584 MW), Austria (1,062 MW) and Sweden (905 MW). According to a report published in 2004 by the Thematic Network on Small Hydro Power (TNSHP), in the then EU15 some 14,000 SHP plants were in operation with an average size of 0.7 MW. There are approximately 2,800 SHP plants installed in the then new member states (EU10) and about 400 in the then candidate countries (Romania, Bulgaria).

As with large-scale hydroelectricity, productivity will be affected by the volume of rainfall - despite increases in capacity, the energy produced by the hydraulic sector dropped by 0.8 TWh and 0.932 TWh between 2004 and 2005, in France and Spain respectively, as a direct result of rainfall deficit.

The EU has the leading small hydraulic power sector in the world, exporting its techno-logies all over the world. It has placed a heavy emphasis on the environmental integration of hydro-power plants in order to limit adverse effects on nature. The European Small Hydraulic Association estimates turnover at €150-180 million a year, employing nearly 200,000 people. New member states represent promising markets. Perhaps small hydropower will provide the security of supply which Europe needs.

Hydropower - opening the floodgates

• Most hydropower plants rely on dammed water which creates a reservoir. Gates on the dam open and gravity drags the water through a pipeline, called the penstock, which leads to a turbine. The greater the height from which the water is falling and the greater the pressure it is under, the more potential energy builds up. This energy is released when the water hits the blades of the turbine, causing them to rotate. This provides the energy needed for the generator to function. Larger plants also have grid energy storage facilities. At times of low-energy demand, excess energy is used to pump water to a higher reservoir, which is released back to a lower one through a turbine, when the energy demand grows.

Hydroelectricity already generates almost 20% of the world’s electricity.