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Archive for November 28th, 2012

Nov 28

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Netherlands — The Hidden Fuel Costs of Wind Generated Electricity

K. de Groot & C. le Pair

(Former Shell & STW, The Netherlands.)
kenjdegroot@mac.com
clepair@casema.nl

 

Summary

Wind generated electricity requires back-up capacity of conventional power stations. This capacity is required to deliver electricity to consumers when wind supply is falling short. To have the non-wind power stations ramp up or down to compensate for the stochastic wind variations causes extra efficiency loss for such power stations. How much efficiency is lost in this way and how much extra fuel is required for this extra balancing of supply and demand is unknown. In this article we attempt to make an educated guess.
The extra fuel required for the efficiency loss must be added to the fuel required for building and installing the wind turbines and the additions to the power cable network. While these extra requirements may be too small to notice when the installed wind power is a small fraction of the total capacity, matters change when wind capacity becomes significant. Based on the German situation with 23 GW of installed wind power, we show that it becomes doubtful whether wind energy results in any fuel saving and CO2 emission reduction. What remains are the extra investments in wind energy.
Introduction.

Wind energy comes for free, but it does not follow that electricity generation using wind is also free. The hardware costs money and energy to build. The energy required for this is typically derived from fossil sources. More importantly, one needs to maintain a conventional back-up power generator capacity roughly equal to the installed wind power capacity.
The wind may be free of charge, but it is not provided in the desired doses. Wind varies. The variations do not match the electricity demand. Because there is as yet no economically viable method to store electricity, the variations in wind generated electricity levels that do not match demand levels have to be met by adjusting the output of conventional power stations. In his recent thesis1 Ummels concludes on the basis of computer modelling studies that such adjustments can be made “without problems” even when wind would generate electricity equivalent to 33% of the Dutch demand.

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Nov 28

epaw7

Australia — Wind farm study aims for quiet achievement

ABC News — November 28, 2012

Researchers are hoping a wind turbine experiment will give them greater insight into the noise problems some people complain about.

An Adelaide University team says it is investigating precisely how the turbines produce noise, especially in the low-frequency range.

They hope they can produce findings which will improve wind farm design and noise control efforts.

Associate Professor Con Doolan said many questions remained about noise sources, particularly in the low frequencies.

“We have a fair amount of knowledge around the noise generation mechanisms but, particularly in the low-frequency ranges, we don’t know a lot about how they combine together,” he said.

“This project is aimed at getting to the bottom of what is creating the noise that can cause disturbance.”

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Nov 28

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The Economics of Wind Power — Submission to the U.K. Parliament

Memorandum submitted by W R B Bowie (WIND 59)

Wind power saves little or no CO2 and other Green House Gases

The fundamental argument in favour of wind power is that despite its very high cost, it produces less CO2 etc. than conventional power plants. This is, however, completely incorrect. Wind saves little or no CO2.

Wind is an intermittent source of power that cannot be ‘turned on’ when required like conventional sources of power. ERCOT of Texas says that they only consider wind power as reliable source of supply for about 8.7% of its name plate capacity. The E.On wind report of 2005 is more pessimistic saying studies show,

“Wind energy currently contributes to the secure production capacity of the system by providing 8% of its installed capacity” and also that this guaranteed supply will, “fall continuously to around 4%” as winds share of the generating capacity rises up to 2020. As an example at 17.30 on 7th Dec 2010 the UK wind fleet of 5200 MW produced just 300 MW; a load factor of 5.8%. At the same time both Germany and Denmark had lower load factors; 3% % 4%

When plotted in a graph the rises and falls of wind’s capacity looks like a comb! Rapid shifts in power are quite unsuited to the user’s requirements. Because of the erratic nature of wind power, almost without exception, the wind power providers E.On, Centrica, Scottish Power etc say that it is essential that wind has ‘back-up’ from conventional sources of power that can rapidly be turned on & off, to match fluctuations in the wind . Whilst they are agreed ‘back-up is needed, there is some latitude in the estimates of the minimum ‘back-up’ needed. Dr Paul Golby CEO of E.On UK, says 90% whilst Mr Rupert Steele of Scottish Power says, “Thirty Gigawatts of wind maybe requires twenty-five GW of backup”

As a consequence of the need for power to match demand, ‘back-up’ plants are run start/stop to match the wind’s fluctuations. We might like use hydro, but UK has insufficient hydro resources, so the ‘back-up’ is probably a fossil fuel plant; usually gas. An open cycle gas turbine [OCGT] is effectively a jet engine, and a combined cycle gas turbine [CCGT] is this jet engine in which the heat from the combustion is collected and used to make steam to drive a secondary generator. TheCCGT produces about 0.4 of a ton of CO2 per MWh. This is 50% more efficient than the OCGT that may produce same amount of power but uses more fuel and this results in about 0.6 ton of CO2 per MWh. When CCGT machines are used to ‘back-up’ wind power the gas plants are switched on & off [to match the wind] often do not reach a sufficient temperature to make steam and thus operate as if they were OCGT plants. Knowing this some powers suppliers just use OCGT as ‘back-up’ to wind.

Since the wind turbines only operate at about 25% of their rated or name-plate capacity* the ‘back-up’ has to supply the remainder, of 75%. Since, as shown above, a gas turbine operating stop/start produces approx. 0.6T/MWh the average is [75% x .6=] 0.45ton per MWh. This is more CO2 [and SO2, Nox etc] than would have been produced by an efficient CCGT working full time; 0.4ton per MWh. On the attached sheet I have shown this together with the costs of generating electricity by wind power. My sheet paraphrases the situation but detailed studies showing little or no saving in CO2 etc as a result of wind power have been produced by Prof G Hughes of Edinburgh University ["Why is wind power so expensive?"]. A Dutch study by Udo, de Groot and le Pair comes to similar conclusions as does the BENTEK report for Colorado and Texas.

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Nov 28

Stethoscope and X-ray.
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Maine — Industrial wind turbines could cause sleep loss, study claims

Nick Sambides Jr. — Maine Sun Journal — November 27, 2012

American and British researchers, including a radiologist from Fort Kent, have published what they claim is the first peer-reviewed study to conclude that people living near industrial wind sites could suffer significant sleep loss and other health problems.

Called “Effects of Industrial Wind Turbine Noise on Sleep and Health,” the study purports to show from data compiled via survey that people living 410 yards to 1,500 yards from the Mars Hill and Vinalhaven wind sites were sleepier during the day and had less sleep at night than people living 2.8 miles to slightly more than four miles away from the site.

“The levels of sleep disruption and the daytime consequences of increased sleepiness, together with the impairment of mental health … strongly suggest that the noise from IWTs [industrial wind turbines] results in similar health impacts as other causes of excessive environmental noise,” the study states. “The degree of effect on sleep and health from IWT noise seems to be greater than that of other sources of environmental noise, such as, road, rail and aircraft noise.”

Industrial wind advocates and entrepreneurs have held that a vast body of scientifically generated data show that wind sites produce no significant harm on people or nature, while those opposed to turbines have said low-level vibrations from them have caused a host of health problems.

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