KKM began commercial operation on November 6, 1972. With a net nominal capacity of 355 MW, the boiling water reactor is a base load thermal power plant that produces electricity round the clock. It is BKW's biggest production plant, covering nearly 40% of the power requirement in the area supplied by BKW. The plant's high availability of, on average, 90% is high by international standards and reflects its reliability and operating safety, as well as attesting to the expertise of its more than 300 staff. This was recently confirmed by the EU Stress Test and an international mission performed by the International Atomic Energy Agency (IAEA). If security of supply in north-west Switzerland is to be maintained, it is important that KKM remain connected to the grid for as long as the plant is able to produce electricity safely and cost-effectively. The importance of KKM for power supply became clear during Hurricane Lothar in 1999. Without KKM, at least 700,000 people would have been without electricity in north-west Switzerland instead of the 300,000 who suffered a power failure at that time. Continued operation of the plant is also a major factor in ensuring the proper transition to power supply through renewable energy.