1.2 Non-renewable energy

By contrast, non-renewable resources cannot be replenished as quickly as they are used. In the case of the fossil fuels that we commonly use this replenishment may take millions of years. The fossil fuels coal, oil and natural gas are also stored solar energy. The solar energy enabled plants and animals to grow. As they died the plants and animals were buried under geological strata and under pressure over millions of years the carbon content has created the hydrocarbon that we are now able to mine and tap.

We can calculate from our use rate of these resources and our estimates of the remaining reserves how long they are likely to last and, hence, how quickly we need to develop alternatives. In addition, it is our burning of these fuels that is increasing the levels of carbon dioxide (CO₂) and other gases in the atmosphere and generating global warming. This, of course, is the other key driver in encouraging the development of alternative sources of energy.

The last big source of energy, and one that is also non-renewable, is nuclear energy. The energy is released from the fission of the atomic nuclei of certain materials, such as uranium. As uranium ore is a mineral with finite levels of deposits, nuclear energy is also non-renewable. We usually consider it separately from fossil fuels because it does not have the global warming impact of fossil fuels. There are, of course, other issues with nuclear power, particularly how we dispose of the radioactive materials that result from the fission process.