The Marine Society & Sea Cadets

As fossil fuels have started to run out, so countries are beginning to use sources of renewable energy. Renewable energy is sometimes called alternative energy. This is because it provides people with an alternative to fossil fuels and other non-renewable energy sources. Alternative energy sources have been developed for two main reasons:

• People are concerned about future energy demands and whether there will be enough natural resources to meet demand.
  
  
• International pressure from organisations and environmental groups concerned about the effects of burning fossil fuels on the environment. The Kyoto Protocol, drawn up in 1997, is one such result of international pressure and this treaty aims to cut the combined gas emissions of industrialised countries to 5% below 1990 levels by 2008 – 2012. But the USA has pulled out of the treaty saying implementing it would gravely damage the US economy and now there is a debate over whether the targets set will be met.
  

Solar, wind, wave and geothermal energies are based on alternative energy sources and this energy will be around for as long as the Earth is, so we don’t have to worry about running out of it. However most LECDs do not have the money or resources to develop renewable energy sources and so renewable energy sources are mainly used by MEDCs.

Solar energy

Solar energy is energy obtained from the Sun’s radiation. Solar heating is widely used for industrial or domestic purposes and is a major non-polluting and renewable energy source. Solar energy can also be harnessed indirectly using solar cells made of panels of semicondoctor material, which generate electricity when illuminated by sunlight.

Solar power is used in space to provide electricity for orbiting space vehicles.

Advantages – solar panels use sunlight to produce electricity, solar power is a clean source of energy and relatively cheap to produce.

Disadvantages – solar power cannot be generated at night or on cloudy days, so homes also have to have a conventional backup system that uses fossil fuels.

Wind power

For centuries, the wind has been used to sail ships and pump water. Now people use the wind to generate electricity. Wind turbines usually have 2 or 3 blades that turn as the wind blows and in turn the blades drive a generator that produces electricity, much like steam turbines. The longer the blades and the faster the wind speed, the more electricity the turbine generates.

Large groups of wind turbines, called wind farms, are connected to electric utility power lines and provide electricity to many people.

Advantages – wind power is a very clean source of energy; no waste or pollution is produced, electricity can be produced whenever the wind blows (at night and also during the day).

Disadvantages – lots of turbines are needed to produce a useful amount of energy, many people think wind turbines are unattractive and noisy.

Tidal power

Tidal energy is obtained by harnessing the energy of water waves: wave power. The first wave power scheme introduced to the UK was the Duck (1974), a floating boom whose segments nod up and down with the waves.

The strong winds blowing across the Atlantic Ocean create large waves, making the west coast of Europe ideally suited for wave power.

Advantages – tidal power can produce a large amount of energy and is relatively cheap to produce.

Disadvantages – wave power hasn’t the potential to be used around the world and the technology needed to produce tidal power is expensive to develop and install.

Geothermal energy

We can also get the energy directly from the heat in the earth. This is known as geothermal energy and it starts with hot, molten rock (called magma) miles below the earth’s surface that heat a section of the earth’s crust. The heat rising from the magma warms underground pools of water known as geothermal reservoirs. If there is an opening through the rock to the surface, the hot underground water may seep out to form hot springs, or it may boil to form geysers.

By drilling wells deep below the surface of the earth to tap into geothermal reservoirs, a steady stream of hot water is pumped to the earth’s surface. Geothermal energy can also be used to produce electricity.

Advantages – there are many potential sites for geothermal energy and many sites are in LECDs.

Disadvantages – we could run out of geothermal energy by drawing so much energy out of the reservoir that it is not able to replenish itself at the rate we’re using it, water from geothermal reservoirs often contains minerals that are corrosive and polluting.