Households Supplied

The latest Ourack wind farm design consists of 17 x 180m turbines with a potential capacity of 105 Megawatts (MW). A 105MW wind farm would typically be expected to meet the needs of just over 64,000 households.

How is this calculated?

To understand how much renewable energy a wind farm could produce during a year you multiply the capacity of the wind farm by the number of hours in a year:

(MW capacity) x (hours in year)
(105) x (365 x24)
105 x 8760

This results in a theoretical maximum generation over a year of: 919800 MWh

This calculation assumes that the wind blows at the optimum wind speed throughout every hour of the year. Due to wind speed fluctuations a typical onshore wind farm produces circa. 30 to 40% of its theoretical maximum per year. For the purpose of this calculation the 30% figure has been used. It should be noted that from the wind assessment work undertaken at Ourack it is considered that the wind farm would produce more than 30% of it theoretical maximum.

To calculate the predicted output of the wind farm the theoretical maximum output is multiplied by the capacity factor (ie 30% = 0.3) (theoretical output) x (capacity factor) 

919800 MWh x 0.3

This results in a predicted generation of 275,940 MWh

Ofgem suggests annual household electricity usage is 4,238.30 Kilowatt hours (KWh). For the purpose of this calculation the figure has been rounded up to 4,300 KWh to provide a conservative result. 

To calculate the number of households that the predicted generation of the Ourack wind farm proposal would power it is necessary to divide the predicted generation by the amount of energy used by each household.

Predicted generation / household energy usage

275,940 MWh / 4,300 KWh
275,940,000 KWh / 4,300 KWh

The calculation shows that 275940 MWh equates to the amount of electricity to be used by 64,172 households.