Earthsummit 2002 - A guide to UK Local Agenda 21 renewable energy projects. Earthsummit 2002
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Solar Power

What is solar energy?

Solar energy is sunlight - without it there would be no life on Earth. The sun itself was formed about 4600 million years ago, it is so big that planet Earth would fit inside it a million times. This enormity creates huge pressure deep inside it and releases colossal amounts of heat and light energy (electromagnetic waves), which streams out into space in all directions. A small fraction of this energy travels about 150 million-kilometres and takes just over 8 minutes to reach Earth. The oceans and land closest to the equator absorb much of this energy.

In a 24-hour period the Earth receives enough energy from the sun to power everything on our planet for the next 96 years!

How can we use solar power?

Some of this vast source of clean, renewable energy can be harnessed and converted to help meet our demand for electricity and heat.
Using three main technologies we can exploit this potential.

Solar Photovoltaic (PV) cells, which convert sunlight directly into electricity.

Active Solar Heating systems, which use collectors (usually on the roofs of buildings) to absorb the suns radiation and transfer it to heat water in a tank.

Passive Solar Design, which is designing and modifying buildings to trap more of the sun's natural heat in the winter months whilst not overheating during the summer.

What's the advantage?

The big advantage solar power has over other energy sources is that it's excellently geographically dispersed - providing a better match to human energy needs. Solar installations can be planned, built and generating electricity close to where they're needed avoiding costs and transmission losses associated with other energy sources.

Buildings can generate their own electricity, heat and hot water using Photovoltaics, passive solar design and active solar heating systems. Future developments could see buildings, which are totally self-sufficient, storing their own energy reserves and not reliant on any external grid-connected electricity.

In many situations solar power is the most cost-effective, efficient and only form of renewable energy waiting to be tapped.

© Ambit Interactive 2002
This web site has been produced with funding from
The Open University
The DTI's New and Renewable Energy Programme
Scottish and Southern Energy plc.