What is Renewable Energy?

Renewable energy comes from energy sources that can be used without becoming depleted. In essence, it is energy from sources other than fossil fuels.

Sometimes, the term ‘renewable energy’ is used to refer specifically to electricity that has been generated without burning fossil fuels. However, whilst it is true that renewable energy sources are primarily used to produce electricity, there are other ways of harnessing them. For instance, space heating and hot water can be provided directly from solar power or biomass, with no electricity involved.

Is Nuclear Energy Renewable?

Although nuclear energy has been called renewable, the majority of people disagree. At present there are plentiful supplies of the material used to produce it; however, these supplies are finite, and once exhausted they will not be renewed.

Energy from renewable source is sometimes also called ‘green’ energy because it is more environmentally-friendly than fossil-fuel energy. Burning fossil fuels causes a build-up of certain gases in the atmosphere, and scientific evidence indicates that this change in the atmosphere is affecting our climate. Renewable energy does not increase the levels of greenhouse gases in the atmosphere, so it is environmentally-friendly, or ‘green’. Nuclear energy produces no carbon dioxide emissions and is not contributing to the greenhouse effect, but it cannot be classed as ‘green’ either, because the waste from nuclear power stations is in itself a threat to the environment.

Renewable Energy in Daily Life

Solar energy, geothermal energy, wind power and the force of moving water can all be harnessed for the production of electricity. Electricity generating stations can also be powered by biomass. The automotive industry is increasingly offering vehicles that can run on fuels from renewable sources. Biomass, solar energy and geothermal energy lend themselves well to heating water and space. There are long traditions of converting wind power and water power into mechanical energy in wind and water mills.

Arguably all these forms, except geothermal energy which originates from the earth itself, are different manifestations of solar energy, since it is the sun that causes winds and tides and provides the energy that enables crops to grow.

What Does Carbon Neutral Mean?

Concerns over climate change are centred on the fact that we are currently putting too much carbon dioxide and other greenhouse gases into the air around us by burning vast quantities of fossil fuels. The composition of the atmosphere is changing, and scientists believe heat that would normally have risen up through the atmosphere and dispersed into space, is now being trapped inside the atmosphere. This is causing the earth’s average temperature to rise.

Biomass crops put oxygen into the atmosphere, through photosynthesis, whilst they grow. So although they release carbon dioxide when they are burnt, over their complete lifecycle they have not significantly altered the composition of the air; in their growing phase they took in carbon dioxide and water and converted it into oxygen and carbohydrates, and in their subsequent phase, as combustible fuel, they combined oxygen with stored energy and released it back into the atmosphere as thermal energy and carbon dioxide.

Fossil fuels are not carbon neutral because they have no effect on our atmosphere until, having been extracted from the earth, they are burned and produce emissions. This is why biomass is called ‘carbon neutral’ and fossil fuels are not.

However, strictly speaking biomass is not carbon neutral, but low carbon. It is practically impossible for any energy source to be completely carbon neutral because normally there are stages in its production, delivery and utilisation that involve the use of other energy resources, and it is almost inevitable that some of these processes will emit carbon.

Why Don’t We Use More Renewable Energy?

Only around 5 per cent of the UK’s electricity is produced by non-fossil fuel power stations, and the proportion of non-renewable energy used for purposes other than electricity generation is also low. However, the use of renewable energy around the country is slowly growing, sometimes for large-scale applications and sometimes on a very small scale. The government has an obligation to increase the proportion of energy obtained from renewable sources within a set timescale, so we are likely to see more Renewable Energy schemes being introduced in years to come.

Renewable energy is an exciting topic. We can see and feel the energy of the sun, wind and sea all around us every day, yet man has still not fully explored all the ways in which we could tap into their power. Research and developmental work is ongoing and renewable energy technologies are advancing all the time; but there may be ways of harnessing these elemental forces that nobody has yet tried. It will be interesting to see what the future holds.