An energy source that is replenished by the nature on its own and its consumption is less than its replenishment is called a renewable source of energy. Wind, solar, tidal are a few examples of renewable energy. Fossil fuel is not because it’s rate if consumption by humans is much higher than it being replenished by the nature.
Another form of energy is nuclear energy. It’s quite efficient but it’s very risky. Also, a nuclear power plant is an expensive proposition. Countries that plan to establish nuclear power plants, need to keep aside a significant amount of money to manage potential disasters occurring out of nuclear power plant.
It seems that renewable energies are quite apt for the upcoming generations of consumers. With people being sensitized about the ill-effects of fossil fuels(pollution) and disastrous effect of nuclear fuels we seem to be having a compelling case for renewable sources of energy. Below a few pictures of renewable energy farms.