Can Wind Compete with Coal?
By Bill Moore
In 2000 the tiny country of Denmark, which is half the size of the state of Maine, produced nearly as much electricity from wind turbines as did the entire United States, 2300MW vs. 2554MW. By contrast, Germany generated an impressive 6113MW from its installed base of modern wind turbines. In fact, both Germany and Denmark are the current world leaders in wind turbine design and manufacture, an industry originally pioneered by the United States and nearly abandoned in the 1980s.
Now wind power is coming back with a vengeance as the fastest growing form of power generation in the world. Yet for all its promise, wind power provides only a miniscule amount of America's energy, estimated at a mere one-tenth of one percent. While coal remains the king of fossil fuel energy in America --providing over 50 percent of the nation's energy needs -- it is estimated at our current consumption rate, which has been declining of late, US coal deposits could last another 600 years.
In a paper published in the August 24, 2001 edition of Science, Mark Z. Jacobson and Gilbert Masters, both of Stanford University challenged the notion the time honored notion that coal is the cheapest form of energy. They estimate that while electricity from a new coal power plant costs between 3.5 and 4 cents/kWh, when you factor in the cost of the federal black lung disease program benefits, the true costs are closer to 5.5 to 8.3 cents per kilowatt hour. They base this on the fact that since its inception in 1973, the program has cost American tax payers $35 billion in benefits. Every year in the United States, some 2,000 coal miners die of the disease (several of whom were personal friends of EV World's editor who lived in southern West Virginia for over five years and counted many miners as personal friends and acquaintances.)
By contrast, with the introduction of modern 750kW and 1.5MW wind turbines and their aggregation into large scale wind farms, the cost of wind generated electricity has dropped from the 38 cents a kWh twenty years ago to 3-4 cents/kWh today. Further improvements in wind turbine technology are expected to see those numbers decline even further, reported Jacobson and Masters.
Because of EV World's interest in clean, renewable forms of energy to power the EVs of the future, we contacted Jacobson to talk about his paper and its implications on the US energy picture.
Jacobson began by explaining what factors contributed to such a dramatic decline in the cost of wind generated electricity. When America dominated the wind energy industry in the late 1970s and early 1980s turbine technology was still in its infancy. Turbines were relatively small and unreliable. This meant costs per kWh were high and this meant tax breaks were needed to help provide investors and developers with the necessary incentives. When many of these tax breaks "dried up" in the early 80s, the industry in the US went into decline. Marginal wind farm developers went broke, as did turbine manufacturers.
Meanwhile, overseas in Europe, particularly in Denmark and Germany, the impact of the oil embargoes of 1973 and 1977 were not lost on the government. With few fossil fuel resources other than Ruhr Valley coal, both countries saw a need to find other, local forms of energy like wind seemed -- pardon the pun -- a natural.
While the Germans and Danes heavily subsidized their wind turbine industries, manufacturers there began to realize that as you build bigger, taller turbines, the cost of electricity production begins to drop. This is due to several factors. Jacobson explained that not only were turbines becoming more reliable, with fewer and fewer breakdowns, but that the higher the turbines are in the air and the wider the blades, the more power they can generate.
"So, what we've seen in the last two to three years... is that the size and efficiency of some of these turbines has improved such that, if these turbines are placed in locations where the wind is sufficiently fast, then the cost of energy from them per-kilowatt-out-produced is equivalent -- the direct cost -- to coal plants and new natural gas plants."
This trend to bigger and bigger turbines continues, Jacobson told EV World. Developers in Europe have proposed constructing a new off-shore wind farm that will make use of a new generation of 5MW wind turbines. Located some 42 kilometers off the coast of Norway, this new mega-farm will consist of 200 of these giant machines, the equivalent of 1,000 megawatts of electricity.
While the "fuel" that powers wind farms is abundant, renewable, clean and, best of all, free, it is also intermittent and somewhat unpredictable. Worst of all, it can't be depended upon the respond to the ebb and flow of electric power usage on the grid. This is one of the major reasons why utilities have, until recently at least, shied away from it, despite its other obvious benefits.
Jacobson responds that of the many misconceptions about wind power, its intermittent nature is one of the biggest.
"Certainly on any given day, at any given hour, you can have variability of the wind," he conceded, pointing out that you can't know what the output of a given turbine in a given wind farm will be at a particular day and time. "However, there are two other ways to look at it. If we have multiple turbines, and when we say 'multiple' we mean hundreds or thousands and that essentially is what you'd have in a wind farm... the intermittency at one location often cancels out the intermittency at other locations."
Jacobson reasons that the more wind turbines and wind farms we have scattered across the landscape, the more reliable the system will become. "There's an inverse correlation, the more turbines you have the more efficient it is." This has an important advantage over our conventional generation system, he argues. The failure of one turbine in a large, multi-machine wind farm, will have negligible impact on the rest of the farm and almost no impact on the connected grid. A similar failure of a generator at a central power plant can have a cascading impact on the entire grid system and it can come without any warming.
As to the question of the unreliability of the wind itself, Jacobson argues that in actual point of fact it is remarkably predictable.
"It turns out that if you average the wind at any given hour over a month, that's a very reliable parameter." For example he says that if you average the wind speed at 3 o'clock in the afternoon over 30 days, this turns out to be a very consistent number month after month, with some seasonal variability. "Even though the wind at one time on one of those days might not be so reliable, the wind speed averaged over a longer period of time, say a month, is a pretty reliable parameter." He contends that this would enable you to predict with a measure of accuracy the wind at any given time of the day over a protracted period of time.
He also observed that based on a recent study by Eric Hirst, that the actual cost of wind intermittence to the grid is something less than 1 percent of the cost of the wind-generated electricity, itself.
He concedes, however, that we will never be able to depend on wind power for all of our electric energy needs. "We don't envision that wind energy will every a hundred percent of the power. We're shooting for somewhere between 20 and 30 percent. So, there are always going to be other power sources, even if the wind hypothetically stopped."
Interestingly, he added that winds tend to peak at about the same time power usage on the grid typically peaks.
Part Two Continued Next Week.
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