Energy Resources and Electricity Generation

We generate electricity in a handful of ways - some of which are better for our planet than others. Although we have traditionally relied on fossil fuels to produce the majority of the electricity that we use in our homes, non-renewables are slowly catching up and overtaking electricity supply as we become ever more conscious of the harmful impact of non-renewable energy on the environment.

Renewable energy

Wind turbines, water energy (hydropower), geothermal energy, solar heating systems and solar cells are renewable forms of energy. As the effects of climate change become more established, renewable energy sources are becoming the preferred method of generating electricity. In 2019, renewable energy sources provided more electricity to homes than fossil fuels since the opening of the UK’s first power plant in 1882.

Wind turbines

Kinetic energy from wind is used to turn the blades of a wind turbine, which is connected to a generator. The limitations of wind energy is that it is dependent on weather - if there is no wind, no electricity will be produced. Also, some people think the turbines are ugly and an ‘eyesore’ on the landscape. The benefits of wind energy is that no polluting gases are produced and there are no fuel costs.

Water energy

Kinetic energy can be harnessed from the movement of waves or tides and used to drive a generator. Hydroelectric power stations create gravitational potential energy by storing water in a dam. When the water gushes through the tubes inside the dam, the gravitational potential energy is converted into kinetic energy which is used to drive a generator. Like wind energy, no polluting gases are produced and there are no fuel costs. It is more reliable than wind energy since tidal movements and waves are constant. The disadvantages of water energy are that they can only produce small amounts of energy at a time and can cause habitat destruction along coastal regions.

Geothermal energy

Thermal energy from hot rocks underground can also be used to generate electricity. Water is pumped down to the rocks through a pipeline which returns to the surface as steam. The steam is used to rotate a turbine which is connected to a generator. The rocks are hot due to radioactive decay of unstable nuclei underground. Geothermal energy is a reliable form of energy and does not produce any polluting gases. However, it is limited to regions of the world where there are hot rocks underground.

Solar cells

Solar cells convert light energy directly into electrical energy and are used in devices such as calculators and artificial satellites. The original source of energy is nuclear fusion in the Sun. No polluting gases are formed but it is an inefficient and expensive method of generating electricity. Furthermore, it is dependent on weather conditions and does not work at night.

Solar panels

Solar panels don’t generate electricity directly, but are used to heat up water. You’ll have probably seen these on the roofs of homes and other buildings. Cold water enters the solar panel and is heated by light energy from the Sun. Warm water leaves the solar panel and is stored in a tank until it is used. Although it produces no polluting gases and there are no fuel costs, warm water is only produced in sunny climates during the day.

Non-renewable energy

Fossil fuels and nuclear power are both non-renewable energy sources. It uses material which cannot be replaced and will eventually run out.

Fossil fuels

Fossil fuels include coal, oil and natural gas. They are formed from the fossilised remains of plants and animals which died millions of years ago. The chemical energy within fossil fuels releases heat energy when burned. The heat energy is used to convert water into steam which is used to turn a turbine which drives a generator. The advantage of generating energy using fossil fuels is that they are relatively cheap and (for now) readily available. They also produce a large amount of energy from a small amount of fuel. The disadvantages are that they release sulfur dioxide and carbon dioxide gases when they burn, which leads to acid rain and global warming respectively. Since fossil fuels are a non-renewable resource, their supply will eventually run out if we keep using them.

Nuclear power

In nuclear power stations, unstable radioactive particles (such as uranium and plutonium) undergo nuclear fission in an controlled chain reaction. The unstable particles release neutrons which bombard other nuclei. The kinetic energy of these particles is used to generate heat energy and convert water into steam. The steam is used to turn a turbine which is connected to a generator (learn more about nuclear fission here). The advantage of nuclear power is that is produces a huge amount of energy from very small amounts of fuel - a million times more energy can be generated from 1 kg of uranium compared to 1 kg of coal. The fuel is readily available and no polluting gases are produced. The disadvantages are that accidents at nuclear power plants can be catastrophic (think Chernobyl and Fukushima) and that the radioactive waste needs to be very carefully disposed of to avoid contamination of the environment. The power stations themselves are very expensive to build and radioactive material will eventually run out.

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