Other renewable energy sources

Wind farms for energy generation are relatively new in concept. A common criticism is their small output. Modern large offshore plant are rated at 5MW. To produce 7% of the UK electricity demand, at least 1,700 turbines would be required, each at the maximum current rating available. Such great numbers would necessitate development of large swathes of offshore coast. Planning permission for massive offshore farms could run into significant difficulties. The RSPB has recently threatened to object to several high profile projects including Shell Flat, Blackpool, due to a large population of wintering Common Scoter (Melanitta nigra) in the area 8.

Solar technology is being utilised increasingly by UK companies but primarily through the use of panels on their property roof, a market BPsolar 9 is exploiting. However, harnessing the sun directly with solar arrays is not a viable option for large scale energy production in the UK using current technology. Further, energy demand is strongest during winter months; when capacity from solar is at its lowest.

Wavegen is a UK company that specialise is generating power from wave action. Their primary product, the LIMPET (Land Installed Marine Powered Energy Transformer) has a capacity of 500kW.

The LIMPET works by utilising the oscillation of waves. An empty shell is filled with sea water as a wave hits shore. The incoming water compacts the air and drives it through a hole in the top of the unit. As the wave falls back, a vacuum created by the waters departure, sucks air back through into the unit. Two turbines are driven by the oscillation, producing power from both the incoming and outgoing wave 10.

A LIMPET was installed at Islay, Scotland, in 2000 and has proven successful with electricity sold to the national grid. The design of each unit is unobtrusive to coastal views. However, until the rating of 500kW is dramatically increased, significant numbers of LIMPETs would be needed to produce a meaningful energy supply. Although the technology is relatively benign environmentally, a large numbers of units would be overwhelmingly imposing on a long stretch of coastline. Additionally, connecting many units together would require expensive cabling over an extensive distance 11.