A DETAILED ANALYSIS OF THEIR ALLEGED FUEL AND CO2 SAVINGS
The rationale behind our politicians´ enthusiasm for wind power and other renewable energies is not rooted in an objective analysis. We shall not speculate here on political agendas or corrupt behavior, but simply explain why wind farms serve no useful purpose.
In Western countries, public energy policy is based on this fundamental premise: wind farms are a mature technology for producing green energy, and are competitive. But, if they are competitive, why do they need enormously expensive subsidies, direct or indirect?
The wind farm industry routinely replies to this question by pointing to the “external costs” of producing energy with fossil fuels. These external costs are, in a nutshell, pollution, CO2, and global warming. The flaw in this line of argumentation is that the external costs in question equally apply to wind farming, as I shall now endeavor to demonstrate in easily understandable language.
I) – Wind farms cause conventional power plants to burn more fossil-fuels per KWh produced.
It is an undisputed fact that anyone driving in city traffic spends considerably more fuel than he would on the motorway. There are two reasons for this:
- An engine burns fuel more efficiently when running at its optimal cruising speed (about 100 kph for most cars).
- An engine burns fuel with low efficiency and produces more harmful gases when it accelerates. Who hasn´t noticed the blue smoke coming out of exhaust pipes when cars accelerate? (black smoke in the case of poorly-tuned diesel engines).
In city traffic, cars accelerate, come to a stop, accelerate again, stop again, etc. This causes more fuel consumption and more pollution. And we must add to this the burning of fuel for nothing when cars are stopped at red lights, of stuck in traffic-jams.
The same happens with fossil-fuel power plants: they consume and pollute more when accelerating and stopping frequently. And the crux of the matter is that wind farms force these plants to operate that way.
Here is how:
A) - When the wind is blowing, fossil-fuel power plants (FFPPs) must curtail their productions because electricity produced by wind farms enjoys priority on
the grid. As there are no batteries large enough to absorb electricity produced in excess of demand, the FFPPs are thus ramped down to lower levels of production. This is necessary in order to maintain the required frequency of 50 Hz on the national grid, failing which there would be crippling black-outs, something a modern economy cannot tolerate.
The optimal efficiency of FFPPs being when they operate at about 95% capacity, this ramping down causes them to burn more fuel, to emit more CO2, and to pollute more for each KWh produced.
B) - Conversely, every time the wind speed goes down, whether or not temporarily, FFPPs must ramp up their production rapidly to avoid black-outs. This ramping up is comparable to the acceleration of an automobile in that it burns fuel quite inefficiently and emits more gases.
As this ramping up and down occurs frequently during a single day due to the high variability of wind speed, fuel consumption, CO2 emissions, and pollution
increase greatly for each KWh produced by the FFPPs. And wind farms are responsible for it.
C) - Finally, when one or more FFPPs must stop producing altogether because an increased quantity of wind-generated electricity has entered the grid, they must continue to spin in stand-by mode, burning fuel and emitting gases but not producing any electricity. This is necessary because wind is unpredictable, and these power plants will be required to ramp-up again at a moment’s notice when wind speed will go down.
Coal-fired power plants need several hours to produce electricity from a cold start. Closed-cycle gas turbines (CCGT) can respond quicker, but not at the flick of a switch. Nuclear plants cannot ramp up rapidly. Hydro power can, but is kept in reserve for emergencies (e.g. a FFPP breaking down). Flick-of-a-switch open-cycle gas turbines (OCGT), which are relatively expensive to operate, are being kept in reserve like hydro or used for peak loads only, i.e. at the time of day when electricity demand is at its highest. In the circumstances, a number of coal-fired or CCGT plants must be kept operating in stand-by mode when the wind is blowing, just in case it would abate rapidly.
A, B and C cause fuel to be burnt for nothing. This is caused by the existence of windfarms, whose "non-dispatchable" (uncontrollable) production must be "balanced", or "backed-up", by dispatchable FFPPs.
The higher the installed capacity of windpower in a country, the higher the number of FFPPs that must be kept running in back-up when the wind is blowing, balancing the erratic production of windfarms; and the more fuel is burnt for nothing.
An example will help understand these constraints of electricity production:
- Suppose a country has 20,000 MW of installed capacity in wind power.
- Suppose that, on a windy day, these wind farms are producing at 95% capacity, i.e. 19,000 MW (there will always be a few turbines in need of repair).
- Now suppose that the wind abates rapidly, and that within 2 hours only 10,000 MW of wind power capacity are actually being used. All things being equal, e.g. the demand for electricity, the grid manager will have to ramp up 9,000 MW into the grid. If he doesn´t have at that moment a dozen or so FFPPs spinning on stand-by, he will not be able to avoid a black-out, or at least a brownout (this is when electricity supply is being cut to certain customers, generally industries that use a lot of electricity). Brownouts already occurred in California and Spain, and a black-out in Germany. Although wind farms were not made officially responsible for these costly disruptions (political correctness oblige), they did play a substantial role.
Recapitulation: extra fuel burnt to back-up wind power
1) More fuel is burnt by FFPPs spinning in standby, assuring against the risk of wind abating.
2) More fuel is burnt per KWh produced when FFPPs are ramped up every time the wind speed inches down.
3) More fuel is burnt per KWh produced when FFPPs are forced to ramp down and operate at a lower level of efficiency when the wind is blowing.
All in all, there is considerable suspicion that wind farms may be saving next to nothing (if at all) in fuel, pollution, and CO2 when their detrimental effects on the operation of FFPPs are considered. Yet these plants are needed to back-up wind power: without them there would be black-outs every time there is a change in wind speed, for the electricity´s frequency on the grid must remain steady at 50 Hz. To achieve this, the grid operator has to match supply with demand at all instants, with temporary variances in grid frequency not exceeding 1%.
Several papers, and a book, have been published on this matter, addressing some of the points raised above:
“The hidden fuel costs of wind generated electricity” - K. de Groot & C. le Pair
“Subsidizing CO2 emissions via wind power - the ultimate irony” - Kent Hawkins
Institution of Engineers and Shipbuilders in Scotland
Wind Power Important Questions And Answers
There are more papers and articles, all raising important questions, all calling for a comprehensive study on the unproved claim that wind farms save on fuel, pollution, and CO2. Unfortunately for taxpayers, consumers, and wind farm neighbors, who all pay dearly for this unreliable energy, no such study was ever made. Arguably, the results would be embarrassing for those governments that have been destroying so much landscape for nothing. This lack of transparency causes a growing number of people to think that wind farms are in fact useless, and just a means for a few to get rich quick at the expense of the many.
Internet is full of warnings from independent engineers, economists, and environmentalists. But the mainstream media ignores them, having abandoned investigative journalism long ago. Political correctness is so much more rewarding for them, and easier to follow than ethics.
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