Hybrid systems combine several electricity production and storage pieces to meet the energy demand of a given facility or community. In a system such as this, PV arrays, wind turbines, and generators can be added as needed to meet growing energy demands and fit the local geographical and temporal constraints. These systems are ideal for remote applications such as communications stations, military installations and rural villages. To develop a hybrid electric system, it is essential to know the energy demand to be met and the energy resources available from the various sources. Energy planners must therefore study the solar energy, wind and other potential resources at a certain location, in addition to the planned energy use. This will allow them to design a hybrid system that best meets the demands of the facility or community.
Where there is political or social need to illustrate ‘greenness’ such as the coming ‘Sustainable’ London Olympics 2012 there are inter-mixed Solar PV, Windmill and in this case a wood chip, Biomass furnace powering the area around the main stadium and Olympic village, which also has solar thermal showers.
PV powered desalination systems use the electricity generated from solar PV cells to drive reverse osmosis of feed water to produce a less saline water. The technology is in its infancy with only a few small-scale plants in operation. However, as water is easier to store than electricity and there is often a degree of coincidence between areas with water stress and high solar insolation, desalination is potentially a good use for surplus electricity generated from solar cells.
If the price of PV technology can be reduced further, PV-generated desalination may become economic. Energy accounts for half of the costs of desalination, which is considerable over the lifetime of a desalination plant.