Hydro power

The leading renewable energy source

Hydro power is the most important renewable energy source for both Vattenfall and the EU’s energy mix. It accounts for approximately 11% of European electricity generation and 60% of total renewable electricity generation.

Ever since Vattenfall was established in 1909 to manage the Swedish government’s hydro power investments, hydro power has played a key role both for Vattenfall and for Sweden as a whole.

Today Vattenfall owns and runs more than 100 hydro power plants – the vast majority of them are in Sweden, although there are several in Finland, Germany and the Netherlands as well. Hydro power accounts for roughly 20% of Vattenfall’s total electricity generation.

Hydro power is derived from the movement of water, usually by extracting the potential energy that water accrues in its natural cycle: evaporation and rainfall create glaciers and lakes from which water flows back down to the sea in the form of rivers. To capture this energy, watercourses are usually dammed so that the flow can be controlled, and the water is then fed to a lower level via a turbine. The flowing water causes the turbine to rotate, and this drives a generator that produces electrical energy. The greater the drop and the greater the flow of water, the higher the capacity.

Hydro power is easy to regulate and generates energy as soon as the water is released. It isn’t dependent on short-term weather conditions or wind, or on time-consuming, technically complex start-up processes.

As a result, it can be used to generate both baseload power (the quantity of electricity that is always needed) and regulating power (electricity generation that can quickly be turned on and off to cover variations in demand and in generation from other power sources).

A pumped-storage hydro power plant is one way of storing energy and balancing out supply and demand for electricity. When electricity generation is high but consumption is low, excess electricity is used to pump water up to a reservoir. Then, when demand is high, the water is released to generate more electricity.

Hydro power is a reliable, cost-effective and renewable energy source that produces virtually no emissions that affect the climate or the environment. But hydroelectric dams do affect the flow of water in rivers and have a significant impact on animal and plant life, including migratory fish. Energy companies are working hard to minimise and offset these effects.

Countries such as Norway, Sweden, France and Austria, which benefit from major differences in terrain and suitable watercourses, derive a large proportion of their energy mix from hydro power. Countries like Denmark and Poland, on the other hand, have completely different natural features and must therefore rely on other energy sources.