Hydroelectric Power

What is hydroelectric power?

Hydroelectricity is power from water in motion. Turbines capture kinetic energy from a stream of fast-flowing water or falling water. This generates renewable electricity.

Many hydroelectric power plants use an artificial dam. These dams create an upstream reservoir of water at an elevated height. The water can be released to flow through a series of turbines on its way downstream.

Pumped-storage hydroelectricity

Pumped-storage hydroelectricity is a way of storing energy for when it's needed. It uses electricity to pump water into an elevated reservoir when demand is low. This can then be released downstream as needed to generate electricity.

It provides no net-generation of electricity but it can help with load balancing. It's also useful for storing over-generation from intermittent sources like wind or solar.

How energy is captured from hydropower

Hydropower converts kinetic energy from moving water into electricity. The source of moving water can be:

• 'Run of the river' which is the natural flow from a body of water
• From a reservoir of water behind an artificial dam (more common)

Using an artificial reservoir allows for more controlled and efficient electricity generation. Water stored in the reservoir can be converted into electricity on demand.

Hydropower generation in Ireland

Ireland has a long history of hydropower generation. It dates right back to the Shannon Hydroelectric Scheme in the 1920s. The Ardnacrusha power plant on the Shannon remains Ireland's largest river hydroelectric scheme.

Other significant hydroelectric installations are Cathleen's Fall (Donegal), Poulaphouca (Wicklow) and Cliff (Donegal). Turlough Hill (Wicklow) is Ireland's only pumped-storage hydroelectricity plant.

Explore our map connected and potential hydroelectric sources in Ireland.