The Low Carbon Partnership
Solar Power
Ocean energy
The image of the Earth as it is seen from outer space shows that the majority of our planet is actually covered in water. In fact, about 70% of the Earth’s surface is made up of seas and oceans. There is a lot of energy in the waters of the seas and oceans and there are three main ways we can capture it for use.
The first way is to tap the energy in waves. Waves are created by the force of the wind over the water and so can be big or small depending on the strength and speed of wind. Wave power turbines harness the kinetic energy that is in the up and down movement of the water’s surface to make mechanical or electrical energy – without producing greenhouse gases. The seas around the UK are a good source for wave energy but the technology is still fairly new and not many of these turbines are yet in use. However, wave power systems are likely to have an impact on the coastline as they can reduce the height and strength of waves.
The second source of ocean energy is the power of the tides. Special marine turbines generate electricity as the water flows past them – in towards shore and out again over the course of each day. The amount of electricity produced depends on the tidal range (the height difference between high and low tides) and the volume of water passing the turbines. This energy can be captured by building a tidal barrage, which is like a big dam across the mouth of a river. Such barrages are expensive to build and can affect the local environment and wildlife by reducing the tidal flow and causing a build-up of silt. However, eight good sites have been identified around the UK which could provide up to 20% of our energy needs.
The third way to get energy from the oceans is to make use of all the heat energy they absorb from the sun. This heat can be harnessed through Ocean Thermal Energy Conversion (OTEC) systems. These systems use the heat in sea water (or thermal energy) to vaporise a fluid, such as ammonia, or to create steam which is used to drive turbines to generate electricity.
These ocean energy technologies are still new and in the process of being developed but they do not cause carbon dioxide or other greenhouse gas emissions. It is also a renewable resource as it will never run out – the water is always moving and absorbing heat. There is a lot of potential for the future – especially in the UK which, as an island, has a large ocean resource.
