4.6.2 Environmental considerations

In spite of the above, there are nevertheless some potential hazards allied to the production of some of the more exotic thin film technologies. The two most promising options, cadmium telluride and copper indium diselenide, both incorporate small quantities of cadmium sulphide, which poses potential cadmium risks during module manufacture. Fortunately, there are well-established procedures governing the handling of such compounds, which are adhered to throughout the production process.
One criticism of early PV modules was that they consumed more energy during their production than they generated during their lifetime. With modern production methods and improved operational efficiencies this allegation is no longer true. The exact energy payback is obviously dependent on the available solar resource and on the degree to which the system is operational. High levels of solar irradiation and a high utilization factor will offer more rapid energy paybacks than if there is less sun and less usage, but typically energy payback will be realized within two years.

 

4.6.3 Space-saving installation

PV is a simple, low risk technology which can be installed virtually anywhere there is available light. This means there is a huge potential for the use of roofs or facades on public, private and industrial buildings. PV modules can be used as part of a building's envelope, providing protection from wind and rain or serving to shade the interior. During their operation such systems can also help reduce buildings' heating loads or assist in ventilation through convection.
Other places where PV can be installed include the sound barriers along communication links such as motorways. To satisfy a significant part of the electricity needs of the industrialised world there is therefore no need to exploit otherwise undisturbed areas.
In the UK, for example, it has been estimated that the country's total electricity demand could be satisfied by solar arrays using only 3% of the land area.