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Old 28th-April-2008, 01:45 PM
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Again, this might be considered slightly off the main point of the thread, but people might find this report by David White commissioned and published by the Renewable Energy Foundation in 2004 interesting.

The author attempts to examine the CO2 emissions reducing potential of wind electricity generation in the UK. However his main arguement is that it has to be taken in the context of the ability of wind generated electricity to integrate into the National Grid. As a result it looks at the effects of integrating electricity produced by wind turbines into the National Grid as well http://www.ref.org.uk/Files/david.wh...ving.12.04.pdf
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Old 29th-April-2008, 07:30 AM
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The BWEA's response to the report I linked to above can be found here, for anyone that's interested in the other side of the debate http://www.bwea.com/pdf/ref_three.pdf
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Old 30th-April-2008, 05:26 PM
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This has probably been posted before, but what the hell:
Energy: the answer is not blowing in the wind | spiked

"John Hutton, the UK business secretary, announced plans yesterday to increase Britain’s production of electricity from wind. According to Hutton, by 2020 the UK will produce 33 gigawatts (GW) from wind power, mainly from offshore turbines, apparently capable of powering 25million homes (1). But actually producing that much electricity from wind is unrealistic, a distraction from the only serious and viable method of producing low carbon, reliable electricity: nuclear.

The reaction of environmentalists to these developments shows how apparently strong principles can be set aside in favour of certain right-on technologies. Try to sink one 15,000 tonne oil platform in the North Sea (as Shell attempted with the Brent Spar platform in 1995) and Greenpeace will vilify you, but announce a plan to plant 7,000 concrete and steel pylons - each weighing 2,000 tonnes - on the seabed and you will be an eco-hero. Pour 60million tons of concrete across the Severn Estuary to build an energy-generating tidal barrage and Sir Jonathon Porritt and his Sustainable Development Commissioners will carry you in triumph through Jerusalem.

The Severn Barrage, essentially a dam across the Severn Estuary to generate power from its 10-metre tides, is equally loved and hated by greens. It will never be built. But, to universal green approval, John Hutton has offered up Britain’s entire continental shelf for industrialisation on a scale that makes the Brent Spar look like as biodegradable as an organic ciabatta.

According to Hutton, ‘Next year we will overtake Denmark as the country with the most offshore wind capacity. This could be a major contribution towards meeting the EU’s target of 20 per cent of energy from renewable sources by 2020.’ The key word in Hutton’s statement is ‘capacity’ because, although it is always claimed that Denmark gets 20 per cent of its electricity from wind power (2), in fact the Danish experience shows that investment in wind is a grandiose and expensive folly – guaranteed neither to supply electricity nor reduce greenhouse emissions.

Denmark’s wasted wind

Most of Denmark’s wind generation is off the west coast, where the electrical grid is better integrated with Norway than with the rest of the country. East Denmark is integrated with Sweden and Germany. Central generation is mostly from coal stations and there are over 700 local combined heat and power (CHP) stations running on gas or biofuel. CHP stations generate electricity and use what would otherwise be wasted heat to supply hot water to surrounding communities (3).

Because wind generation is immensely erratic and hard to forecast it is almost impossible to incorporate it into the grid without compromising reliability. Detailed study of inflow and outflow between Germany and Scandanavia demonstrates that as much as 84 per cent of west Denmark’s wind power is exported to Norway (at a loss to Danish consumers of about £100million) (4). Norway’s electrical supply is 100 per cent hydro, generated by water falling through turbines in river dams, and the Danish wind power is simply used to pump water back up into reservoirs – in effect, storing the electricity (and currently the only practical way to store power). Hydro and wind are extremely complementary, but the people of Denmark are paying the compliment and the people of Norway being flattered.

Currently, the Danish Wind Industry Association (DWIA) admits: ‘Danish wind power only contributes to adequacy [of supply] with a capacity value of zero.’ That is, wind’s generating capacity does not guarantee any of the basic and essential electrical supply. When wind production increases to a 50 per cent ‘share’ (in 2025), according to some DWIA projections, Denmark will have to export unusable excess power at a large economic loss but neighbouring countries will make a profit by selling back essential baseload electricity.



Even when electricity generation from wind farms is stable, its unpredictability means it cannot prevent the burning of coal at slow-responding coal stations. Instead, because it comes at very low marginal cost, it replaces more expensive electricity supplied by the slightly adaptable CHP stations. But since domestic and industrial customers rely on those same CHP stations for hot water, the stations must keep running, burning fuel in the process. By not producing and selling electricity as this hot water is produced, the CHP stations become less economically viable.

Paradoxically, such CHP stations are an essential component of Britain’s ‘alternative energy future’. CHP represents the ‘decentralised microgeneration’ beloved by the Sustainable Development Commission (SDC), an environmental quango that advises the UK government, which wants a future of ‘self-sustaining local communities’. A massive expansion of wind power in the UK will make CHP much less attractive by undercutting the price of electricity and forcing CHP stations to turn on and off – making them both environmentally and economically inefficient. In 2004, partly for such reasons, Elsam (then the power generation company for west Denmark) told a meeting of the DWIA and Danish government that increasing wind power does not decrease CO2 emissions – because it forces CHP stations to run with less carbon-efficiency. A 2003 study by the Tallinn Technical University in Estonia showed that trying to incorporate wind with CHP can actually increase fuel consumption and emissions by eight to 10 per cent - completely eliminating any CO2 benefits from wind (5).

So, the wind power Denmark sells to Norway for use in hydro stations saves not one molecule of CO2 and by interfering with CHP stations may actually make emissions worse. In east Denmark, the baseload is regularly topped up from the Swedish grid – half nuclear and half hydro – so Denmark’s total electricity supply is, actually, about nine per cent nuclear.

Wind turbine dominoes

Germany should be another case study for Hutton before he goes too wild on wind. A study of the German national grid for E-On (the largest operator of wind turbines in Germany, with 43 per cent of the total) shows that as wind generating capacity increases, the proportion of that capacity that can be incorporated into the grid actually decreases. When there are sudden high winds across a large number of turbines, the unexpected excess electricity can overload the system. The more turbines that are connected, the less unrestricted ‘access’ each wind farm can have to the grid and the greater the controls needed to prevent overloads.

Currently, the German grid with its European interconnections acts as a very large sink into which surplus wind-generated electricity can (usually) dissipate, but even so, large new grid extensions and special switching measures are needed to prevent grid overloads when wind power peaks. Consequent supply failures can spread from northern Germany in a loop through the grids of Holland, Poland and the Czech Republic. The potential impact on other countries means that Germany can no longer expand wind farms in isolation but must consider the impact on a wider European level (6).

By 2015, Germany will have 36GW capacity from wind, but only six per cent of that capacity can be considered as guaranteed coverage of maximum seasonal load. And traditional power stations (coal, nuclear, gas) with capacities equal to 90 per cent on the installed wind capacity must be permanently online (7). If that six per cent figure holds true for Britain, Hutton’s 33GW worth of new British wind power would represent only 1.64GW of actual electricity capacity – or about the same as two advanced nuclear power plants.

On rough calculations, building a 33GW offshore wind capacity will use as much concrete and steel as building 78 medium-sized nuclear power plants, which would produce 62.4GW of reliable electricity (opposed to 1.64GW from wind) - not far short of the UK’s entire 75GW demand.

Continued...
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Last edited by Wobs; 30th-April-2008 at 05:29 PM.
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Old 30th-April-2008, 05:27 PM
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Nuclear battleground

The only rational hope for secure and clean energy in the near future is nuclear power. Those who believe in a future of social progress underwritten by energy abundance must take on the PR challenge themselves. Anyone who expected Gordon Brown’s unchallenged political authority to guarantee a new generation of nuclear plants looks like being sorely disappointed.

However, it is unlikely that even ‘new’ greens ‘armed with peer-reviewed science’ will be any more amenable to reason than old-fashioned greens – with their ignorance and contempt for peer-reviewed science.

Last year’s SDC report on nuclear power makes interesting reading. On almost every measure, the detail of the SDC report actually favours the nuclear option. It recognises that nuclear has an excellent safety record, that it could cause a large and rapid decrease in CO2 emissions, that modern reactor design substantially reduces decommissioning costs, that the nuclear power programme’s waste is just a fraction of Britain’s radioactive waste (the majority being from the military and hospitals), and that nuclear power is cheap and reliable (.

Of the 18 voting Sustainable Development Commissioners, two voted ‘Possibly’ to nuclear power, five voted ‘Not now’, and eight voted ‘No’. Voting was along predictable lines: only two members have a science or engineering background, four have no obvious affiliation, but 12 commissioners either make money promoting ‘sustainable energy’, or are members of solidly anti-nuclear lobby groups like Greenpeace and Friends of the Earth. From the voting, it would appear that three of the greener members did not bother to turn up and the rest did not read the report (9).

To come out against nuclear power, the SDC resorted to double-think and twisted rationalisation unrelated to true energy issues. In his commentary on the report, SDC chairman Sir Jonathon Porritt argues that nuclear power could be seen as a ‘get out of jail free card’ – not inflicting the kind of pain we deserve from our irresponsibility toward the planet; nuclear might compete for investment money against ‘renewables’; it could use up too much ‘political leadership’ and distract attention from alternatives; it might also set a bad example for gullible foreign countries; and encourage rogue regimes to build nuclear weapons.

Warheads into watts

In fact, instead of proliferating atomic weapons, nuclear power can destroy them. The disarmament treaties of the 1980s have released uranium and plutonium from warheads for use in reactors. Since 2000, 30 tonnes of enriched uranium have been released to civilian nuclear stations annually and displaced over 10,000 tonnes of uranium from mines – about 13 per cent of the world’s annual requirements (10).

Uranium is not in short supply – contrary to rumour. There is as much uranium in the ground as there is tin. There has been little new uranium exploration for 20 years, but already enough uranium has been discovered to last at least until the end of the century at current levels of use. The increasing efficiency of nuclear reactors means that they can now produce almost twice the electricity from the same amount of uranium. Even if the uranium ran out, new reactor designs can employ thorium as fuel and there is three times as much thorium in the ground as uranium.

And unlike our gas, much of which comes from unstable parts of the world, 40 per cent of the world’s known uranium supplies are in Australia, Canada and the USA. As with other mineral and energy resources, increasing prices makes new exploration more economically viable. Analogous with other minerals, there is probably 10 times more uranium easily available to be found by new exploration.

Modern reactors also produce much less waste than previous generations – only 10 per cent of the volume of low-level waste as before – and much of the high-level waste can be reprocessed into new fuel if supplies of ore were threatened or the costs of exploration and extraction escalated way beyond current projections.

In Washington DC, Adrian Heymer, senior director of the Nuclear Energy Institute says that once-hostile public opinion in the US is turning around. ‘When you tell people that 70 years of electricity for a typical four-bedroom family home leaves just one Coke can full of waste, they are impressed and reassured. And all the waste from the whole US civilian nuclear power programme over the last 49 years would cover just one football field, about twenty feet high. Compare that to the trillions of tons of carbon waste and chemicals released into the atmosphere from fossil fuels – not to mention 5,000 people killed in coal mining accidents every year.’

Britain’s existing nuclear plants were built without a thought for decommissioning, hence the unexpectedly high costs; though these are much less than is supposed. It is estimated that decommissioning costs for each reactor range from £1.3 to 1.8 billion – after an active and productive life of up to 40 years. For perspective, even before the latest wind expansion proposals, the government is currently spending £2billion a year on subsidies for alternative energy with almost nothing to show for it in terms of either electricity or carbon savings.

New reactors are built on modular designs that can be taken apart as easily as they are put together and decommissioning costs are built into the price of electricity charged to the consumer.

Challenging the green agenda

An unquestioning green agenda so dominates the news, media and commentariat that proponents of nuclear power tend to keep their heads down – although public opinion polls continue to show quite high approval for nuclear power.

Brazil’s experience in 2001 provides both comfort and guidance. By taking on misrepresentations, misunderstanding and lies and exposing the dishonest tactics of Greenpeace on many issues, the Brazilian Nuclear Energy Association undermined the credibility of a campaign against a new nuclear power plant (11). Pro-nuclear groups got their facts right and ran a well-organised campaign. By the end, the president of Greenpeace was forced out, its ‘aura of credibility’ was destroyed and the organisation simply ceased to campaign against nuclear power in Brazil for over five years.

The message for Britain must be ‘armed only with peer-reviewed science we demand a new generation of nuclear power stations. Abundant, clean, secure energy is our right, and will help save the planet.’

Dr Rob Johnston is a freelance writer on the environment, health and science."
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Last edited by Wobs; 30th-April-2008 at 05:30 PM.
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Old 1st-May-2008, 10:30 PM
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Good posts Wobs.
Variability is a major problem for most renewables.
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Old 2nd-May-2008, 04:08 AM
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What about marine energy systems (tidal flow - barrage or current - or wave motion)?

The UK distribution network (local, regional and national) was designed when coal was cheap and the consequences of fossil fuel consumption were unknown; it was all good as far as the Victorians were concerned and the Georgians carried on investing in the network on the same basis. Of course the CEGB (or those engineers who began their careers as apprentices for it and have always thought of the grid on that basis) could be forgiven for basing arguments about grid stability on what they know and are comfortable with.

Of course the money to continue investing in our grid (pitifully ignored for most of the last 40 years!) has to come from somewhere. It used to be Government owned but the industry was broken up through the process of privatisation, back when enough people were convinced that private business could do a better job of providing power to the UK than the clumsy Governments of the 60s and 70s had done - in their opinion!

I'm not arguing for nationalisation of our power infrastructure (although the recent Government bail out of British Energy and Northern Rock have shown that isn't impossible), but that we have to move on from a time when we thought making money was all that mattered (the usual background and caveats apply! i.e. I have a mortgage too).

The reserve power needed to support increased penetration of interruptible supplies from wind could come from spinning reserve (fossil or biomass powered!) but equally the grid could be designed around non-thermal but predictable supplies of electricity. People with narrow persepctives are more of a problem than the grid we've built on the principles applied as it was developed when releasing millions of tonnes of sequestered carbon into the atmosphere was acceptable!

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Last edited by MarkuisMellvile; 2nd-May-2008 at 10:00 PM.
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Old 3rd-May-2008, 07:58 AM
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Quote:
Originally Posted by MarkuisMellvile View Post
The reserve power needed to support increased penetration of interruptible supplies from wind could come from spinning reserve (fossil or biomass powered!)
It could and does. But spinning reserve is very inefficient and there is a break-even point where the energy required for keeping the spinning reserve on line starts to exceed the energy produced from the variable sources.
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Originally Posted by MarkuisMellvile View Post
but equally the grid could be designed around non-thermal but predictable supplies of electricity.
Maybe not so easy. For example, tidal is predictable, but the cycle isn't particularly convenient. On a regular basis, slack water is bound to occur when there is the greatest demand for power. Intermediate storage could be used to match supply and demand - a Dinorweg type scheme. But, to put it in context, it would need to be about three times the size of the Itaipu dam.

I'm with Wobs on this. I think we have no choice but to go nuclear.
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Old 6th-June-2008, 06:45 AM
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Certainly instantaneous wind variance of wind speeds could pose a problem for power flow stability. Hopefully with the right loads and adequate backup for the grid network via grid backup generators, most of these issue can be avoided.
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Old 6th-June-2008, 08:09 AM
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Quote:
Originally Posted by LMagic007 View Post
Certainly instantaneous wind variance of wind speeds could pose a problem for power flow stability.
Given the inertia of the rotating components (you can't instantaneously change the speed of the turbine)* and the transient response of the power electronics, the system can deal quite well with short term fluctuations in wind.
*Nor can you change the speed of the wind instantaneously for same reason.

Last edited by Besoeker; 6th-June-2008 at 08:25 AM.
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Old 6th-June-2008, 08:51 AM
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Good work wobs. Great info... Keep it up...
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