Thornholme Field Wind Farm would consist of nine wind turbines, each a maximum of 2 megawatts, with maximum tower heights of 69 metres and rotor diameters of 82 metres.  

These dimensions will provide a maximum height to blade tip of 110 metres, typical in size of modern turbines and similar to those you may have seen at the nearby Lissett Airfield (which are 125 metres to tip).

Once a turbine is in operation it will be monitored remotely with maintenance personnel making periodic visits. A turbine is expected to have an operational life of approximately 25 years. After this time it will be decommissioned in order to return the site to its previous state. 

How the figures are calculated

 1) Predicted Output

capacity of wind farm (MW) x capacity factor
x
hours per annum (8,760 hours)
=
predicted output (MW hours per annum)

‘Capacity factor’ is the % of the wind farm’s maximum output expected over a year. 100% would mean that the wind turbines were generating their maximum output all the time, a little like driving a car at maximum speed all the time. In reality, the wind is usually blowing and the wind turbines generate electricity most of the time, at a greater or lesser proportion of their maximum possible output.

2) Households Supplied

predicted output 
÷
average UK electricity consumption per household per annum
=
number of households electricity needs supplied

3) Carbon dioxide emissions avoided

wind farm output
x
carbon dioxide savings per kWH
=
carbon dioxide emissions avoided

Some information on the figures used above

Capacity factor

We used a figure of 0.28%. This is a UK mean, using data from 1999 to 2008, taken from “Chart 1, Special Feature: “Load factors for wind technologies” (within “Energy  Trends” September 2009) (DECC).

Annual household electricity consumption

We use a figure of 4.39 MWh. This is calculated by dividing the GB domestic sector sales by the number of domestic points of supply, taken from Table 5a within the Digest of United Kingdom Energy Statistics 2009 (DECC).

 CO²  savings

The figure we use is 610g/kWh. Explanation of how we get to this figure as follows:

In a real-time scenario during the day-to-day running of the UK power system, renewable generation can be assumed to be displacing emissions from 'marginal plant' (i.e. the fuel likely to be displaced by wind power coming online). According to the National Grid Company (ASA Adjudication, 2007) the marginal plant consists of coal and gas fuelled generation, the proportion of which varies throughout the year and at any given time depends on the relative prices of these different electricity sources. When gas fired generation is favoured, wind power was likely to displace coal and vice versa. Therefore, taking account of the variations throughout the year, the emissions saved by wind power lies between the two figures for coal (880g CO₂/kWh ¹) and gas (370g CO₂/kWh ¹). Between 01/04/2008 and 31/03/2009 coal and gas provided 31.1% and 34.9% respectively to the overall electricity mix.¹ The addition of new wind energy generation would therefore save approximately 610g CO₂/kWh as it displaces fossil fuel generation from the grid mix.

¹ Fuel Mix Disclosure Data Table (DECC) for the period 1 April 2008 - 31 March 2009

Wind turbines displace CO2 emissions helping to reduce global warming

Out Newton Wind Farm in the North East