Photovoltaic modules are solid-state devices that convert sunlight directly into electricity with no rotating equipment. Photovoltaic systems can be built in any size, are highly reliable, and require little maintenance.
World-wide photovoltaic sales are about 100MW annually. The major problem limiting the widespread use of photovoltaics is the cost of manufacturing the sheets of semiconductor materials needed for power systems.
At today's efficiencies a piece of desert land about 2 miles square could host a solar electric generating plant with the power production capacities of a large nuclear or coal plant.
Despite their high costs, photovoltaic systems are cost-effective in many areas remote from grids, where another sources are impractical or costly. For grid-connected distributed systems, the value of photovoltaic electricity can also be high because the electricity is produced during period of peak demand, thereby reducing the need for conventional peaking capacity. Photovoltaic equipment may be installed close to the sites where it is consumed, thereby reducing transmission and distribution expenses together with increasing reliability. Small, grid-connected photovoltaic systems may be competitive today where distributed generation has particularly high value. Many such niche applications will provide early markets for photovoltaics systems. As photovoltaic prices fall, markets will expand rapidly.
Photovoltaic prices have fallen sharply since the mid 1970s although prices have stabilised over the last few years because demand has grown faster than supplies. There is, however, good reason to be confident that prices will fall substantially by the turn of the century. There are several alternative paths by which costs can be reduced. Systems based on thin films of materials such us amorphous silicon alloys, cadmium telluride, or copper indium diselenide are particularly promising, both because they are well suited for the application of mass-production techniques and because the amounts of active materials required are small. Another strategy calls for concentrating sunlight on small, highly efficient photovoltaic cells using inexpensive lenses or mirrors.
A projection of the cost of PV systems assumed in this analysis is given in Table 9 .
Other assumptions are:
The avoided costs are (Cladding costs-(Wiring + Fixing) costs):
Wiring costs: £25/m2
The cost of the PV electricity
The cost of the electricity can be predicted in p/kWp as:
Table 10: Avoided cost of PV electricity, in £/m2 .
All calculations have been done for the daytime period: 9:00-17:00 hs
Table 11: Site availability for PVIB in m2 .
Total generating capacity between 9:00 and 17:00.
Table 12: Present PVIB generating capacity in the UK .
And the total generating capacity in GW for 2020 between 9:00 and 17:00., for different times of the year is
Table 13: 2020 PVIB generating capacity in the UK, in GW .