Wednesday, December 13, 2006

Wind Farms and Nuclear Waste.

There is no direct connection between the terms in the title, but if wind turbines are placed in the wrong place, they will not produce the amount of electricity forecast for them, and hence we will rely increasingly on other forms of electricity generation, probably nuclear. Almost certainly, nuclear power will play a major role as part of the mix chosen to secure electricity production, labelled until 2050, although falling oil supply may well change world geopolitics sufficiently that "Plan B's" will need to be drawn out before then. Friends of mine who are "into" such things, tell me that I should not be worrying about any of this, as time (as we know it) will end when the Mayan Calender finishes in the year 2012! It is interesting that this is also the year of the London Olympics - surely some coincidence? My friends may well be right, but I would prefer to keep a more pragmatic view in reserve, in terms of energy and resources as we currently perceive them!
Wind turbines are wonderful devices, but just how wonderful they are depends on where you put them. Organisations that place them ostentatiously on the roofs of their premises in regions with little or highly intermittent wind flow, are making a statement more than any significant contribution to the national grid (most do not have local electricity capture technology installed, so to be of any use it would have to feed the grid). To whit, a new study by the Renewable Energy Foundation concludes that England and Wales are not windy enough to allow large wind turbines to operate at the rates claimed for them. This foundation is a charity that aims to evaluate wind and other types of renewable energy on an equal basis, and it based its study on data supplied by the energy regulator Ofgem for over 500 wind turbines. Even on wind farms in Cornwall, which might be expected to be most efficient, being subjected to gusts from the Atlantic, operated at at average of just 24.1% of capacity. Now my understanding, as I have written before here - and received some censure too, that I was being far too pessimistic! - is that 20% is a reasonable value for the "capacity factor" according to long experience in Germany and Denmark (a very windy place - so much so that the trees grow at an acute angle, sloping against the wind!). Mid-wales fares similarly at 23.8%, the Yorkshire Dales are slightly better placed at 24.9% and Cumbria tops the bill at 25.9%. It is only north of the border that a 30% average was achieved, in southern Scotland (31.5%), Caithness, Orkney and Shetland (pretty exposed places) made 32.9% and offshore (North Hoyle and Scroby Sands, on opposite sides of the mainland) where 32.6% was recorded.
The report concludes that the best siting for wind farms is offshore near major cites so that the greater force of the winds can be harnessed, and relatively little is lost compared with the transmission through the national grid from remote areas such as northern Scotland and its isles. Apparently, all the government's wind targets are based on a capacity factor of 30% (why?, I ask), and clearly if they are placed anywhere on land south of the border this will not be met. Some real "turkey farms" (of the wind variety) were found in lowland England, the worst being the turbine close to the M25 at Kings Langley, Hertfordshire at the Headquarters of Renewable Energy Systems, the green energy phalanx of the Robert McAlpine (construction) Group, which limped home at 7.7% - ouch!

Nuclear power has another horror story to report. I am not forthrightly anti-nuclear, and with various reservations, mainly over what to do with the long-term nuclear waste, and potential radioactive "dirty bomb" material for terrorists (either by blowing the stuff around London with a small explosive device, or crashing an aircraft into a running reactor, say), I accept that certainly in line with government policy, it will be with us for decades to come. Through breeder technology based or either thorium or uranium, creating respectively uranium-233 or plutonium-239 as a final fuel, nuclear power could supply us with electricity for hundreds of years and maybe it will. Fast breeder reactor technology was explored in the UK at Dounreay, now closed but regularly in the headlines as pieces of plutonium keep appearing on the beach there. The first of the Dounreay reactors to achieve criticality was the Dounreay Materials Test Reactor (DMTR), in May 1958. This reactor was used to test the performance of materials under intense neutron irradiation, particularly those intended for fuel cladding and other structural uses in a fast neutron reactor core. It is fast (high energy) neutrons that are required to convert uranium-238 to plutonium-239.
More fuel fragments have been discovered, and the Dounreay Particles Advisory Group (DPAG) has recommended that the UK Atomic Energy Authority (UKAEA) close the beach immediately adjacent to its north Scotland nuclear site where they were found. This is the latest find of radioactive fuel residues at various offsite locations, including Sandside beach and the Dounreay foreshore. The cat was put among the pigeons when one particle was detected on a beach at Dunnet, which is in fact several miles distant to the east of Dounreay. The particles are about the size of a grain of sand. The pollution is a legacy of many years worth of poor practice in waste management, which left thousands of shards of irradiated fuel rods from reprocessing being released into the environment through a number of different routes. I remember a story that waste was dumped into a shaft near to a cliff, whose geology was less sound than originally thought, and it cracked releasing some of the plutonium it was supposed to contain "for thousands of years". DPAG has announced that trials are to be undertaken of "robots" for recovering particles from offshore sediments. There is a lesson here of a "duty of care" to future generations, that currently applauded methods of radioactive waste disposal really will sequester radioactive waste for thousands of years as claimed, until the radioactivity has died down to near background levels.

There are many who favour renewables, and that includes me, although I have pointed out manifestly that the gargantuan amounts of energy we use currently will not readily (if ever) be supplied from renewable sources. Energy efficiency is key, either through technology and probably simple frugality if ends so necessitate, but we should power-down to whatever kind of life this engenders and not run the profligate train of plenty over the edge of a cliff; we must begin to apply the brakes before it steams-on out of track. I am not enthused by the idea of going back to an agrarian economy; while I have enjoyed reading the novels of Thomas Hardy, that is in part because of the simple and beautiful language he used which describes a life based around agriculture, that was technologically simple but humanly harsh.

1 comment:

James Aach said...

The comments to episode 2 (among others) of my online, insider nuclear power novel discuss some of the same points on generation capacity you are raising. See