I note this morning that 2,000 wind turbines are to be installed in the southern North Sea by the Irish company Airtricity and ABB, the Swedish based engineering group, which will provide 10 Gigawatts (10,000 Megawatts) of power, sufficient it is thought to supply 8 million homes. This is part of the provision of a European supergrid, linking wind farms from the Baltic Sea, the North Sea, The Irish Sea and the Mediterranean. The great advantage of this system is that essentially the wind will always be blowing somewhere, and it is proposed this will lead to constancy of supply, which is a problem with a conventional wind farm: i.e. either you put up with a very up-and-down supply - which would be no good for most electrical devices such as computers and televisions - or you store the electricity in some way, e.g. by charging batteries of some kind or more nebulously, but as some think, in the form of hydrogen produced from that electricity by the electrolysis of water.
This sounds like a fantastic idea in principle. However, if I understand the proposal correctly, providing 10 Gigawatts (GW) of full capacity wind energy by 2000 turbines means that the capacity of each is: 10 x 10*9/2000 = 5 x 10 *6, or 5 Megawatts (MW). I know that turbines rated at 2 MW exist, but I thought that 5 MW was still on the drawing board, but I guess it will take some time to approve the plan and so the technology might well have moved on by then. O.K.
Now in terms of an actual generating capacity, since turbines don't run at full capacity most of the time, if ever, we need to multiply that figure by the "capacity factor", which is reckoned on considerable Danish and German experience at a maximum of 0.2. In other words we would get 0.2 x 10 GW = 2 GW in total from the 2000 turbine farm. So each home would get 2GW/8 million = 250 watts per unit. Now this is a useful amount, and using energy efficient light bulbs it could certainly light most houses, but it couldn't boil a standard electric kettle (about 2 kW) , but it could boil a lower capacity one if you simply waited about 8 times longer.
The annual electricity consumption of a typical U.K. house is about 3500 kWh/year or about 10 kWh/day. So at 0.25 kW (250 watts), this might supply 0.25 x 24 = 6 kWh/day or 2,200 kWh/year. If we work on more energy efficient devices too, then we are not far off our requirements. I am hopeful that this might work in fact, at least for the purpose of providing a domestic supply.
The 2000 turbines are to be installed in the southern part of the North Sea between Britain, Germany and the Netherlands. The companies involved have emphasised that the construction of the power grid itself will enable free access of electricity trade between European countries, which has always been a hurdle. A cable linking the grids over 1,000 km would stretch the length of an average weather front, and so would collect wind power from each farm contained in the network, to provide a constant level of power for those countries that are linked up to the grid, and get around the "on-off" aspect intrinsic to a single farm, i.e. the peaks and troughs are averaged out to a near constant baseline value.
I think this sounds promising. However, we still need to address the problem of how to substitute for cheap oil, and the cheap fuel that we get from it, in short order. The "super-grid" does not help here, and nor is it intended to. Certainly it would help delay the problem of "Peak Gas" (which much European electricity is made from) the date of which has been revised down to about 2030 from the 2100 I heard originally.
The success of the scheme depends on it getting regulatory support and financial backing from a bank (the European Investment Bank, say) and appropriate industrial partners. I wish it well.
2 comments:
In regards to your blog on "massive new european wind farm", I would like to mention that your calculations for the amount of energy produced by offshore wind projects seems to be pessimistic in the least. It is noted from experience that even offshore projects with technical problems resulting in a turbine availability of 50-60%(such as Horns Rev) achieve a higher capacity factor than you stated. The real capacity factors of offshore wind farms are more in the order of 40% and greater as demonstrated in the following excerpt from the International Energy Agency's report on Offshore Wind Experiences:
"Production data are available for the Nysted and Horns Rev wind farms in Denmark. In 2004 Nysted saw a capacity factor of just under 40% while production in the first four months of 2005 yielded a capacity factor of over 47%. Horns Rev saw major technology problems in 2004 resulting in unavailability of 30%-50% of the turbines throughout the year. Thus, its full-year capacity factor is only 26% in 2004, while during the first four months of 2005, when the turbines were fully operational at all times, the capacity factor reached just over 53%. Given that 2004 was considered an average wind-speed year for the Danish climate, long-term capacity factors can be expected at around 40% for Nysted and around 45% for Horns Rev, meeting or even exceeding initial expectations." (Please see: http://www.iea.org/textbase/papers/2005/offshore.pdf for more info)
Also, calculations using the above mentioned capacity factor of 40% would result in 4,380 kWh/year per home if 8 million homes are to be supplied by wind farms, which is more than enough according to your estimates of average U.K. household consumption of 3,500 kWh/year. 10*10^9 Watts*24hrs/day *365days/year*0.40Cap.Factor = 35.04 TWh/year, divide this by 8 million homes and one gets 4.38 MWh/year!
Cheers,
Patrick
Engineering Student,
University of Guelph,
Canada
Hi Patrick,
thanks for getting in touch, and for the information, which is most interesting! If indeed we might expect about "double" the capacity factor of 0.2, as you say, that would cover the average U.K. household consumption of "electricity". However, there is another 20,000 kWh/year of additional heating capacity that needs to be found per unit too: a typical value for the U.K., and which is currently provided mainly by burning natural gas. By living in energy efficient buildings, around 50% of this requirement for "space heating" could be cut (ideally, at any rate); however, a significant amount of energy in additional to the prevailing electricity demand still needs to be found. Ideally and ultimately this should be done without using gas, now that the U.K. is a net importer of this fuel, to ensure "security of supply". How this will be done I am not certain. Some argue for it as part of the case for nuclear, implying that we simply need to generate more electricity and to use that for heating purposes. Alternatively, some appropriate mix of renewables, nuclear, coal and gas, so long as it is available to be imported into the U.K., could provide additional electricity, in combination with microgeneration and efficient CHP systems. I think the solution will be determined according to a system of localised energy economics, with a decreasing reliance on a national grid system.
Cheers,
Chris.
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