Around 10 square metres of solar collectors is sufficient to cover a quarter of the heat requirements of an average detached house in our part of the world. A photovoltaic system with the same size supplies one quarter of the electricity requirement. The path from the heat or electricity generation to the consumer is extremely short. Photovoltaics can be flexibly integrated in buildings, in consumer goods and in vehicles. Energy supply could not be any easier or more decentralised than that.

 

 

Theoretically, the world's energy requirements could be completely covered by solar energy over an area of 700 times 700 kilometres in the Sahara. The challenge lies in utilising this potential technically and economically. Solar power stations in the Sahara would first have to bridge the very wide distance to the electricity consumers – a challenge unsolved to date. Initial experience with solar thermal power stations in California and Southern Spain is very promising. They already provide electricity generated by the sun regionally at competitive prices. By using heat accumulators this electricity is available with the same output around the clock.

 

Advantages due to consumer proximity

 

But why roam so far afield: Just because theoretically up to 50 % more solar energy could be collected in the desert it does not make the solar harvest in Central Europe bad. On the contrary: Its advantages act best for the user in-situ. With solar panels the energy consumer becomes a producer who makes a direct contribution to the energy transition. Electricity and heat generated from solar energy make us independent of imports of fossil energy sources. Once the system has been installed the running costs cannot subsequently rise. In the medium term, the price of electricity produced from solar energy on a house's own roof will be less than the end user prices for electricity from the socket. Here a photovoltaic system directly protects against rising electricity prices.

 

 

Due to know-how and economic power, the conditions for fast, mass market launch of cost-effective electricity generated from solar power are far better in industrialised countries than in Africa. In developing countries, electricity generated from solar energy is nevertheless the ideal way to decentralised electrification as the basis of social and economic development.

 

 

10 m² photovoltaic system generates approximately 900 kilowatt-hours electricity per year.

This corresponds to ca. 25 % of the annual electricity consumption of an average household

10 m² solar collectors generate approximately 4,500 kilowatt-hours heat per year.

This corresponds to ca. 25 % of the annual heat requirements of an average household

Solar systems pay on almost every roof in Germany.

In 2007, around 1.5 million photovoltaic systems and solar collectors were installed in Germany.