Decommissioned Nuclear Power Plant as System Services Providers

The ongoing changes of the power system with decommissioning of several nuclear power plants and large-scale introduction of variable power production without direct connected generators will probably result in a situation where there is a lack of reactive power and inertia.

The lack of reactive power could reduce the possibilities to transmit power in the north-south direction, giving a challenging power balance with electricity trapped in northern Sweden. Lack of inertia could in worst case make it necessary to reduce the output from the largest units, to ensure the grid availability if the largest unit is disconnected. Decommissioned nuclear power plants could play a role in providing system services, but it would require investments and costs to provide these services.

A conclusion of this work is that it is easiest and probably most financially viable to carry out as few modifications to current design as possible. The current lack of economic incentives makes it highly improbable that nuclear power plants will be modified to provide system services. To realise this potential, the value of this kind of services must first be recognized by TSOs and integrated into the electricity market.