Renewable Energy

Renewable Energy: What is it?

The term “renewable energy” describes energy sources which occur naturally in the environment and cannot be depleted as they are used. Renewable energy sources include wind energy and solar energy, among others. These are green power sources—clean-burning, non-depleting energy supplies that won’t pollute the planet or cause any other long-term environmental issues.

Why use Renewable Energy?

Using renewable energy sources rather than fossil fuels such as gas, oil, and coal are desirable for several reasons. First, supplies of these fossil fuels are limited—they will eventually run out, and steps must be taken to provide alternative energy sources to replace them. Second, burning fossil fuels causes pollution, most notably the emission of greenhouse gases such as carbon dioxide that contribute to global warming and the Greenhouse Effect. Burning fossil fuels also causes air pollution and acid rain, both of which have a negative impact on the health of ecosystems and habitats around the world.

By signing the Kyoto Protocol, the UK government has committed to reducing greenhouse emissions by at least 12.5% by the year 2012, and to reducing carbon dioxide emissions by 60% by the year 2050.

To help meet this goal, the government has pledged to create alternative energy sources such that 10% of UK electricity will come from renewable energy sources by the year 2010, with the intention of doubling this figure by 2020. Currently less than 5% of the UK’s electricity comes from renewable sources.

What Alternative Energy Sources are Available?

There are several candidates when it comes to searching for an effective solution to the energy problem. An efficient supply of green power from renewable sources might include the following:

• Wind Power
• Solar Energy
• Hydroelectric Power
• Geothermal Energy
• Bio-fuel
• Atomic Energy

Each of these energy sources has some good and bad points, and has the potential to be an efficient source of power in different situations.

Wind Power

Wind is an enormous and never-ending supply of green power, and has already been harnessed and used as a power source for several centuries, in the form of windmills. With cost-effective technology to harness the power of wind already developed, this type of green power is the most popular choice for a clean, renewable energy source. The turbines that generate wind energy work in the same way as windmills do, and the energy they generate is stored in batteries for redistribution through the UK energy grid. The only real downside to this type of energy generation is, of course, that on windless days no energy is generated—however, as more “wind farms” are placed throughout the country, back-up energy can be stored for such situations.

Solar Energy

Capturing and storing the sun’s energy is a popular way of reducing electricity requirements in many green homes. Solar power can be used to heat water, and the sun’s energy can be captured using solar panels or solar cells. Solar panels can be efficiently integrated into the roof of a building, and provide quiet, pollution-free energy.

The main disadvantages of solar energy are that it can only be captured during the day, and that energy capture is reduced on days of medium to heavy cloud cover. However, batteries can be used to store solar energy. Another consideration is that providing solar energy to a home involves large start-up costs, however over the twenty to thirty year life of the solar energy system, very little is required to maintain the system.

Hydroelectric Power

Hydroelectric power harnesses the energy created by running water, and converts this energy into electricity. This is an efficient technology which is widely used in many countries; however in the UK less than 1% of energy is derived using hydroelectric systems. If all possible sites of hydroelectric conversion were developed in the UK, the total energy production would meet around 3% of the country’s electricity needs (the current figure is around 0.8%).

Geothermal Energy

Geothermal energy is heat energy stored deep within the earth. In some areas, this heat rises to the surface of the earth, and can be used to heat water. There is currently one geothermal power plant operating in the UK, and ground source heat pumps are becoming increasingly popular in UK homes. This is an extremely efficient method of generating electricity however the geological requirements of harnessing geothermal energy make it a limited option for use in this country.

Bio-fuel

Bio-fuel is any substance, whether solid, liquid or gas, that is derived from biological material. This broad definition can include almost any combustible biological substance—from cow dung to raw plant materials, alcohols and oil. The most common use of bio-fuels is in powering vehicles, with many new car models able to run on biodiesel (made from oil and fat) or alcohols such as ethanol and butanol.

The main down-side of bio-fuels is that, unlike most other renewable energy sources, the combustion of such fuels produces greenhouse gases, making bio-fuel the least green of the green power sources.

Atomic Energy

Also known as nuclear energy, atomic energy technology harnesses the heat generated by the splitting of atoms. This process is called nuclear fission. Approximately 20% of the UK’s energy is generated using this technology. Atomic energy generation is extremely efficient and produces no greenhouse gases. The most significant draw-back involves safety issues in the handling and disposal of the radioactive waste that is a by-product of atomic reactions. However, the UK government is stringent in adhering to safety policies and there are regulations in place to ensure that atomic waste is disposed of safely.