Electricity Demand refers to the amount of electric power that is required by consumers at a given time. It varies throughout the day and night, as well as throughout the year due to seasonal changes in temperature and other factors. The peak load or maximum demand for electricity occurs during hot summer days when people use air conditioning and other cooling appliances more frequently. In contrast, the lowest demand usually happens at night while most people are sleeping. Electric utilities must be able to generate enough power to meet this fluctuating demand, which is why they have a variety of generation sources such as coal-fired plants, nuclear reactors, natural gas turbines and renewable energy facilities like wind or solar farms.