Wind Farm (2): A comparison

Information » Wind farm
Cartoon of wind farm and power station

For many of us, it is hard to envisage exactly what impact the proposal would have on our surroundings. Here I have attempted to draw some comparisons between the proposal outlined by Airtricity and Rugeley power station - something with which we are familiar.

Generating capacity

Bagot wind farmRugeley power station
Maximum power generation capability 18.4MW Maximum power generation capability 996MW
Actual power generated varies with wind conditions. Over a year many low land sites average less than 20% of the maximum possible Can generate maximum power continuously (except when closed down for planned maintenance - usually off-peak)
NOTES:
1. The least certain aspect of this is the "power factor" - or the proportion of time for which the wind farm will generate electricity which is dependent on the wind. In recent years the actual results obtained have been consistently lower than predictions - this may be due to climate variation or optimism! The figure quoted (20%) is typical for similar sites south of the Scottish border and does not take account of the turbine design or anemometry data collected by Airtricity.
2. A simple calculation shows that you would need around 250 wind farms similar to this to generate the same amount of electricity as the Rugeley power station. In reality, as you can't store the electricity and wind power is intermittent, you could not actually replace it.

Means of generation

Bagot wind farmRugeley power station
Fuelled by the windFuelled by coal
The proposed turbines would each have a maximum generating capacity of 2.3MW and be able to function over a range of wind speeds. Coal burnt to heat two boilers which generate steam to drive two 498MW CA Parsons turbines
The fuel is renewable, costs nothing and is delivered free when the wind blows The fuel comes from finite stocks, has to be purchased and arrives in fifteen trains every day
Generation is self starting when the wind blows at a speed of at least 2.5 metres/second Two 25MW Rolls-Royce open cycle gas turbines are used to "cold start" after a complete shut down. Bringing back from cold to full power takes around 4 hours

Visual impact

Bagot wind farmRugeley power station
Height to top of turbine blade is 110 metres (361 feet). The tower supporting the 82 metre diameter blades will be 69 metres high Height of the cooling towers is 114 metres (374 feet) and of the chimney stack 183 metres (601 feet). The proposed addition of a de-sulphurisation plant will replace the existing chimney with two 183 metre flues
The wind farm will be on a ridge 155 metres above sea level The power station is on the floor of a valley and 65 metres above sea level
Wind turbines have a relatively narrow profile but can draw attention to themselves as the blades catch and reflect sunlight Power stations - especially the cooling towers - are bulky and also emit steam and smoke which emphasise their presence
NOTES:
1. The visual impact of wind farms is one of the most contentious aspects, with proponents claiming they are things of beauty adding interest to the landscape. Others are vehement in their view that these are industrial machines which are out of place in, and a blight on, the countryside.
2. What is clear is that while conventional power stations are usually low lying due to their need to be by a river, wind farms by their nature have to be in higher and exposed locations.

Employment,economic and social impact

Bagot wind farmRugeley power station
Once constructed, operation of the wind farm will be carried out remotely and any repairs or maintenance will be performed by specialist engineers who visit the site as needed - so no long term employment will be created The power station has around 140 directly employed staff - many living in the local area. Additionally, they employ some locally based contractors for work on the site.
Although the estate where the turbines are located will benefit from the revenue earned from generation, little of this will find it's way into the local economy. Through the use of local staff and services, the power station does contribute to the local economy.
With no staff employed, once in operation the wind farm will have few links with the local community. The power station contributes to the social life in Rugeley with a programme of school visits, annual firework display and also acts as the base for a local band and other clubs.

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