Offshore wind turbines are much taller than onshore wind turbines but their visibility is far less. This is because in Ireland offshore wind turbines will be located several kilometres from the nearest shoreline. At 7-10 km the turbines will appear to be about the height of your thumbnail (not thumb!) held at arm’s length –see picture above; this is an angle of about 1 degree.
In comparison, the Poolbeg Chimneys in Dublin, when viewed from Sandymount Strand, would make a vertical angle of about 7 degrees at the viewer’s eye and a typical onshore wind turbine, at a setback of 500 m will make an angle of about 15 degrees.
Clearly, the visual impact of offshore wind turbines is very much less than for onshore wind energy. It should also be remembered that the scale of offshore wind farms, in the hundreds of megawatts, can achieve generation capacities equivalent to many onshore projects. For example, one 400 MW offshore wind farm with 50 turbines would replace 25 onshore wind farms of 20 MW each (an average onshore size), not counting the effect of higher and more consistent wind speeds offshore.