Load-Following Capability of German Nuclear Power Plants

Currently, nuclear power plants are used in Germany to cover the base load and are predominantly utilized in continuous operation at nominal load. At the same time, the Federal Government is pursuing the goal of continuously expanding the amount of renewable energy used for generating electricity. Its share of the electricity supply is supposed to account for at least 30% in 2020 and to continuously grow thereafter. A significant share of the growth of renewable energy is based on technologies feeding the grid at fluctuating rates (e.g. wind power). A consequence of this is that the residual load, i.e., the load to be covered by conventional power plants (coal, gas, nuclear power), will fluctuate strongly to an increasing degree with the growing share of electricity supplied from renewable sources. In the current scientific debate, there is a strong disagreement regarding the degree to which the nuclear power plants can meet the requirements of an electrical system with a large share of renewable (i.e., fluctuating) feed being preferentially fed into the energy grid.

The purpose of this TAB-project is to identify the points where scientific consensus prevails and – on the other hand – to disclose the issues for which there is no consensus and reflect on the reasons for this. To this end, the project will present the current state of knowledge and the existing gaps in our knowledge, determine the demands for flexibility on the fleet of conventional power plants, especially the nuclear power plants, which result from the further expansion of using renewable energy for generating electricity, and illuminate the technical, operational, and possibly the licensing possibilities and limits of the load-following capability of German nuclear power plants. The main result will be a discussion of the question of how far the capacity for load-following operation of nuclear power plants is compatible with the demands for flexibility on the fleet of power plants as well as the economic factors that accompany flexible operation of nuclear power plants.