Renewable energy, often referred to as clean energy, comes from natural sources or processes that are constantly replenished. For example, sunlight or wind keep shining and blowing, even if their availability depends on time and weather.
Literally 'to make new again', a renewable resource is one that is naturally replenished with time, like the growth of new organisms or natural recycling of materials. Renewable energy is any energy production which uses one of these resources.
Renewable resources do not have a fixed quantity - more can always be generated. However, if the rate of use exceeds the rate of renewal - that is, the source is used more than it's being recreated - its continued use will become unsustainable.
Generally, renewable energy is taken to mean any of the following:
- Solar power
Resources are considered non-renewable if they take a very long time to be created (e.g. fossil fuels) or if their creation happened long ago and is not likely to happen again (e.g. uranium).
Primary energy flows are almost always renewable. On the other hand, biofuels are renewable and definitely count as fuels.
Renewable power is booming, as innovation brings down costs and starts to deliver on the promise of a clean energy future. Renewables are increasingly displacing “dirty” fossil fuels in the power sector, offering the benefit of lower emissions of carbon and other types of pollution.