Renewable energy is power which is delivered from infinite sources. Sun, sea, wind, the earth's heat, and plant and animal sources - otherwise known as: Solar - Hydropower - Wave/Tidal power - Geothermal power - Wind power - Biomass and Biofuel.
Fossil fuels - gas, oil, coal - are finite, they will run out eventually. Though the debate still runs on as to how long fossil fuels will last - it makes sense to look at other options before they disappear and to use power that does not have an environmental cost.
Sustainable energy is power that is both renewable and does not have a significantly negative effect upon the environment. That's a very broad term - the environment. Environment is a large player in power sources. Whilst renewable energies are, by and large, clean, utilising them can incur environmental challenges including damage to wildlife habitats - interruption of scenic views. These Issues have affected wind farm, tidal and hydropower schemes.
Nuclear power, whilst clean, cannot be classed as sustainable as the residue is highly polluting and is not renewable - the sources are themselves finite. The mining of uranium carries its own carbon legacy and nuclear waste remains dangerous for over 100 years. There is no known method of reducing its potential toxic damage.
What of the future?
Where Renewable Energy is used - will tell you some of the initiatives that are going on around the UK. But here, we would like to mention just one of the interesting research studies that are going on. This work entails harvesting the energy we expend doing every day tasks.
Sitting at the computer screen we can emit around 100 watts of energy - the footsteps passing through a London railway station in the rush hour could power 6,500 LED light fittings. Heel-strike generators are being researched by the US Military - currently producing 3-6 watts of power.
The list is endless of sites that could redirect energy in this way - motorways, railway arches, dance floors - a fascinating area to watch.