Written question WQ83141

Geothermal energy refers to any heat derived from the ground, from depths of a few metres to multiple kilometres beneath the Earth’s surface. The deeper you go down in the earth the hotter it gets. However, the rate of increase varies dependent on the location and rocks. Iceland has the advantage of very hot temperatures that can be used for geothermal heat and power. The geology of the UK is different to that of Iceland, which limits this potential source of power to certain areas, such as Cornwall, where there are several projects underway.

The evidence on the geology of Wales indicates the rate of increase in temperature with depth is lower than the UK average. This means that the cost of drilling boreholes to the depths required to access rocks hot enough to drive a petrothermal power station is likely to be prohibitive in Wales.

However, opportunities have been identified for shallower ground source heating and cooling using resource from flooded abandoned coal mines and in urban areas with shallow groundwater systems. We are committed to conducting detailed, local area energy planning across Wales, which will include identifying where shallow geothermal energy can be used to decarbonise the heating of local buildings.