With the exponential depletion of fossil fuels, global warming and pressure from environmental groups, there is a clear need to find alternative and renewable energy resources. Hydroelectricity has long been a popular source of power but has downstream implications, which are not always popular.
Nuclear power is popular with governments but not environmentalists. While offshore wave energy has been explored, it does not appear as feasible and practical as wind power.
For those countries with a large population density, few energy reserves, limited exports and the increasingly higher cost of fossil fuel imports, alternative and renewable energy resources are extremely attractive.
With the possibility of fossil fuel supplies being interrupted, together with rapidly diminishing reserves, Scandinavia and Spain were among the first to use the available technology, with more countries considering the option. Consequently, offshore wind farms are springing up around the world. There are currently 13 sites planned around Britain alone.
A wind farm positioned 80km offshore is still visible from the coast due to the size of the towers and rotor blades. The larger six megawatt turbines are 80 metres high and have tubular towers of six metres in diameter at the base. Current offshore wind farms are 6km from the coast, about 10 sq km in area, and contain 30 turbines. Understandably, with diminishing available space and complaints that they are a blot on the landscape, there are difficulties in finding suitable sites on land, the blades and generators producing beating and whining sounds respectively. Friends of the Earth is rapidly becoming unpopular for suggesting that the Hong Kong government should invest $1.1 billion in 46 turbines on a Lamma island hillside.
Offshore wind farms, thus, appear to be the only viable option. The turbines need a start-up wind speed of about four metres per second; the wind speeds in Hong Kong average six metres per second. Hong Kong has many unoccupied offshore islands with shallow waters, which make such projects viable. While offshore construction costs are higher than on land, offshore energy production is higher.