Daylight is a highly desired form of lighting (see Section 7.3.1) but fails reliably every day. Consequently, the developed world relies upon artificial light for much of the time. With very rare exceptions, this lighting is powered by electricity. Electricity is a refined fuel that is expensive to generate and to distribute. The generation of electricity often involves the burning of fossil fuels which itself sends carbon dioxide into the atmosphere. The end result of the accumulation of carbon dioxide in the atmosphere is believed to be global warming and climate change.