About ten miles north of Ramsgate, in the middle of the Thames Estuary some 175 offshore wind turbines have been installed and are now operating, as wind turbines operate, in their own misunderstood fashion. If it is windy, and not too windy, the turbines generate electricity. The publicity claims that the wind turbines will generate enough electricity for 470,000 homes but the publicity is imprecise. There are only 22.5 million homes in the United Kingdom and to power them all will need another 50 arrays of similar turbines but unfortunately it is not as simple as that.
The wind turbines produce electricity intermittently; when the wind does not blow, not a single home will be powered by this array. When the wind blows too strongly – more than about 20 metres per second, the turbines will shut down. When there is no demand for electricity the turbines will have to dump the electricity somewhere. It may be exported or it may simply be wasted as we have not developed a way of efficiently storing electricity in an environmentally friendly and cost effective way.
Because of this intermittency every wind array needs a backup source of energy. The backup must be in the form of a permanent “spinning reserve” which of course is fossil fuel based and inevitably emits greenhouse gases. So if we had 50 arrays of 175 offshore wind turbines we would need a spinning reserve of the fossil fuel electricity capacity for about 20 million homes.
This may seem to make wind power a rather foolish enterprise on a large national or international scale. Nevertheless you cannot expect governments to behave logically when it comes to renewable energy and the UK government spends about £1 billion a year in making wind farms profitable for their owners. That scale of foolishness is only dwarfed by the UK government subsidising fossil fuel energy mainly by charging Value added tax at the lowest rate of 5%, instead of the usual rate of 20%.
The solution is that renewable energy must be subsidised but not in a way that defeats the rationale of renewable energy. The best subsidy should be reserved for renewable technology which can store the energy generated, such as solar water heating, which needs no spinning reserve but merely the kind of back up that very home already has.
Filed under: carbon dioxide, carbon emissions, climate change, electricity, energy, global warming, microgeneration, solar, solar energy, solar panels Tagged: | genersys, offshore wind turbines, soalr water heating, solar, subsidy for renewable energy, wind, wind turbines