Harnessing Solar Energy
Photovoltaics (PV)
Photovoltaic cells convert sunlight into electricity. A large number of these cells, which are made from silicon, are made into panels or tiles, which can be mounted on south-facing roofs. This is a technology that is advancing technologically extremely quickly. The calculation below is based on PV panels.
Potential Annual energy capture
from PV for T&D
= 16,001 MWh/y in 2008
rising to 16,875 MWh/y by 2030
(Individual household potential gain
where suitable = 3.38 MWh/y)
Solar Hot Water (SHW)
SHW collectors are either ‘flat plate’ or ‘evacuated tubes’. Flat plate collectors consist of a black surface with water pipes enclosed within an insulated box. This fairly ‘low tech.’ system can be home made to produce efficiencies of 50-60%. Evacuated tubes collectors comprise a series of twin walled glass tubes enclosing a black collector tube which has a vacuum to reduce heat loss, these can reach efficiencies of 90% but would be impossible to construct at home. The hot water collected is transferred to the domestic hot water system by an additional coil in the hot water tank. They are the most cost-effective micro-renewable on the market at present.
Potential Annual Energy Capture
from Solar Hot Water in T & D = 23,703 MWh/y in 2008
rising to 25,000 MWh/y by 2030
(Individual household potential gain
= 2.50 MWh/y)
(n.b. All industrial and commercial premises could use SHW as could all the touring campsites and holiday parks. The output from SHW is directly proportional to the area of the collector. One constraint is therefore the area of the collector that can be accommodated, but the main constraint is the summer time demand and hot water storage, unlike electricity in PV, solar heated water is more difficult to move from place to place).
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