The Case against Windfarms
The Case Against Windfarms is an authoritive, referenced document written by Dr John Etherington ( © Dr JR Etherington).
16. Some comparisons - odious and otherwise
Emission of CO2 by a single Boeing 747 airliner exceeds the saving by a 50-60 MW wind ‘farm’
Probably the most remarkable and damning comparison of wind power is to contrast it with aviation as a source of man-made CO2. See Appendix 2 for calculations.
A Boeing 747 airliner on average during a year's operation emits much more CO2 than is displaced per year by a 50-60 MW wind power station. The
The airliner’s daily emission is some 400 tonne CO2/24 h compared with between 181 and 362 t CO2/24 h displacement by a Cefn Croes-sized station depending on to fuel proportion in the wind displaced generating mix – see Section 5.
Ergo - each 747 crossing the British coast (every few minutes) is responsible for more continuous CO2 emission than the displacement of CO2 emission even by the
The ‘greenhouse effect’ of the aircraft is considerably worse than a ground level CO2-emitter. According to RCEP (2002) "The total radiative forcing due to aviation is some three times that due to the carbon dioxide emissions alone." This is a consequence, inter alia, of injection of the CO2 into the high troposphere.
Thus in terms of CO2, each Boeing 747 adds some 182,500 t CO2 to the atmosphere each year but this has the warming effect of in excess of 500, 000 t of CO2 generated at ground level.
Given that government’s 2010 target for CO2 saving by renewable generation of electricity is 9.2 million tonnes, this is outweighed in greenhouse effect by less than 20 airliners! It is apparent that wind turbines are no more than a ‘green’ smokescreen to persuade the public that ‘something’ is being done.
Road traffic versus windpower
What ‘they’ say
“The avoided annual CO2 emissions from a 100 MW wind project is equivalent to taking 34,000 cars off the road.” (www.eere.energy.gov/greenpower/conference/9gpmc04/high.pdf )
The instantaneous power output of a small car at motorway speed is about 50 kW (Hayden 2004). Thus a 2.0 MW wind turbine at 30 % load factor, producing an average power output of 600 kW corresponds to about a dozen cars driving on a motorway. However one has to be circumspect in comparing with the 'car at speed' figure as no car is driven continuously in this way. The annual average is a different matter as it takes into account the majority of the time when the car is stationary.
In terms of CO2 emissions a small car will be emitting about 18 kg CO2/h at average motorway speed and commercial vehicles. much more. A 40 tonne truck averages about 32 litres of diesel fuel per 100 km and emits about 70 kg CO2 per hour (see Appendix 2 for sources).
Taking an annual average, with the vehicle stationary for much of the time, Hayden (2004) suggests that a small car dissipates a continuous 2.25 kW in which case the 2.0 MW wind turbine is equivalent to about 270 cars.
What can a wind turbine support?
The wind power companies say that a 1.0 MW wind turbine “supports” 600 to 700 homes (Section 6. Homes supplied by a wind 'farm').
However, few people understand how this number is calculated and it is maybe better visualised in terms of familiar domestic appliances.
It is often said that a 2.0 MW wind turbine can boil only 300 kettles. This is a slightly misleading comparison as a kettle takes only 2 or 3 minutes to boil and so the average output of our turbine would heat, say, 7000 kettles an hour and tens of millions per year.
It is better to compare with a continuously operating appliance such as the old fashioned radiant bar fire, without a thermostat. Each bar consumes 1 kW continuously.
A 2.0 MW wind turbine generates an average of 0.6 MW, at 30% load factor (i.e. 300 kW) so on average during the year it could supply electricity for just 600 fires.
However because of intermittency, on many days it will supply none and on very windy days it would run maybe 2000 fires. The intermittency has to be ‘ironed-out’ by feeding through the conventional electric network which provides backup much of the time.
Saving consumption – an example of energy efficiency in lighting
Energy-saver lamps can be bought for £2.00 - £3.00. A lamp rated at 20 W is of equivalent brightness to a 100 W incandescent lamp and so each one in use saves the consumption of 80W.
The Energy White Paper (DTI, 2003) says that by 2010, the renewables industry will receive £1 billion per year from the Renewables Obligation and Climate Change Levy and all consumers will pay this. If we spent this sum to give free energy-saver lamps it would provide over a third of a billion! This is ludicrous number, as there are only 24.4 million homes in the
However buying 24.4 million lamps a year would displace the equivalent of 325 MW of continuous generation if they were used for just four hours a day (see Appendix 2). This would represent a capital expenditure of about £50 million per year – less than the cost of the Renewables Obligation paid for the equivalent amount of renewable generation - and it would save considerable money for the consumer.
Wind power in 2004 provided an average of just 221 MW of generation (DUKES 2005). Thus, in ROC buy-out price subsidy alone this exceeded £62.5 million. One is reminded that CPA (2005) concluded that "The Renewables Obligation is currently at least four times more expensive than the other means of reducing carbon dioxide…”
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