In public buildings lighting accounts for about 40% of the electricity costs. If you multiply this figure by the number of kindergartens, schools and universities, town halls, local government buildings and government departments, libraries, swimming pools and hospitals, then the total is enormous. Lighting in public buildings is currently consuming far more energy than necessary, with all the negative side-effects such as high running costs, electricity bottlenecks and damage to the climate. That can easily be changed.