Just off the World Heritage Jurassic coastline there are plans for a large offshore wind farm called Navitus Bay. A consultation process ended last year. Most of the referenced data used in the following few posts has been dug out of the CDROM produced for this. An online link to the main document I use is HERE and on the CDROM it is PEI3_Ch2_NavitusBayWindParkProject.pdf
As Offshore windfarms go, there is nothing remarkable about Navitus Bay. Most of the data in the following few posts, shocking as it is, will equally apply to similar schemes elsewhere in the country.
But before I start, I feel I need to emphasise how poor offshore wind farms are at generating electricity. We need to keep this in mind when we look at the massive environmental damage done by their construction.
So first of all let us cut through some of the propaganda.
The first fantasy figure that gets promoted is the maximum output rating – a figure that is rarely (if ever) reached. Navitus Bay gets promoted as a 1GW+ plant. Or about the same capability as Sizewell B. Which is frankly, absurd.
There is an enormous difference between the maximum rating and the actual averaged yearly output (the Capacity Factor or CF). The documentation for this project optimistically touts a Capacity Factor of 35% or an annual averaged rating of around 350MW.
The actual national offshore CF from 2008 to 2012 is recorded by DECC
Using the DECC recommended "unchanged configuration" table, an offshore geographically averaged CF of 35% has only ever been achieved once. But remember, Navitus Bay is near Bournemouth. This is not the Irish Sea. Navitus Bay will inevitably be performing at the lower end of the average. Those few per cent matter. If the final CF turns out to be 28% and not 35% then the averaged power rating will have been overstated by 25%.
Even then, like all wind turbinery the typical daily output will be significantly less than the Capacity Factor. This is because the Capacity Factor gets inflated by unpredictable short duration high energy events.
So bear in mind that while this is physically a large project, in reality, the final result would be a SMALL intermittent power plant.
In the next few posts I'll solely deal with the environmental damage done to the sea bed by offshore wind farms. Damage you will not be able to see. But damage that will take hundreds and maybe thousands of years to heal. And all for a puny amount of electricity, a vacuous feel good fashion statement and of course, lots and lots of money.
Tomorrow I start with undersea cabling and the required trenching ploughing and general trashing of the sea bed that goes with it. So how much undersea cabling am I talking about? Try 300 miles worth. And the trenches? how about up to 2 metres deep and 10 meters wide...