The annual home equivalent for each project has been calculated based on an annual energy yield estimate for the project and an average annual domestic energy consumption figure.
Estimated energy yield
The annual wind resource available at each site has been derived from the long term average wind speed recorded in the UK Wind Speed Database (NOABL: http://www.bwea.com/noabl/index.html), extrapolated to the proposed hub height of the turbines. The derived wind speed is then fed into a Rayleigh probability distribution to estimate the frequency at which each wind speed will occur yearly. The wind speed distribution is then combined with the published power curve for a target wind turbine to give a yearly gross energy yield. The gross yield figure is then factored to account for losses, including: wake losses (calculated using a computer model), availability losses (3%), electrical losses (3%) and control losses (3%).
Annual domestic energy demand
This calculation has been based on average annual UK household electricity consumption of 3,300kWh as stated in "Updated Household Energy Bills Explained" (2013) Ofgem, available online at: http://www.ofgem.gov.uk/Media/FactSheets/Documents1/household-bills.pdf
Energy yield (kWh) ÷ domestic energy use ( kWh/household)