Alternative energy is any source of energy that does not use fossil fuels. It includes solar energy, wind energy, geothermal energy, hydroelectric energy, biomass energy, tidal energy, ocean wave energy, and nuclear energy. Each of these has advantages and disadvantages, including with regard to cost and to environmental and health effects.
Much effort is currently being devoted to replacing fossil fuels with alternative energy in an attempt to slow the rate of climate change and other adverse effects of their use. However, many people view the progress as being excruciatingly slow, as indicated by the fact that the use of coal and other fossil fuels has continued to set new records.