The sun
The solar energy that reaches the Earth amounts to 15,000 times the energy we use in the world today.
The term ‘solar energy’ usually refers to energy captured directly from the sun's rays in solar cells and panels.
Limiting factors
The amount of solar energy that can be captured is limited by factors such as latitude, season, time of day and the wavelength of the rays. Productivity is also influenced by clouds and solar-cell efficiency.
15 per cent efficiency rate
Solar cells are advanced products – complicated to produce, but easy to use. However, today’s cells can only convert about 15 per cent of the solar energy that reaches them into electricity. By comparison, a hydro power plant can convert 90 per cent of the kinetic energy in water into electricity.
The future
Solar cells are still far too expensive to use in large-scale electricity production. They are practical when other energy sources are lacking, like lighthouses and emergency telephones, and also in developing countries. They are also utilised in different niche applications such as clocks and calculators. Research on solar cells is being conducted in many countries – and the use of this energy source might increase significantly in the future.
At the moment, this energy source only accounts for a tiny share of our energy supply. The existing production sites are mainly local initiatives.
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