Friday, June 02, 2006

Could windmills replace Nanticoke?

In recent posts I have been beating the drum for nuclear power as the basis for a low-carbon electricity system. This system would itself be the basis for a fundamental shift away from fossil fuels and toward electricity as the prime driver of the 21st century economy. That is, more of the equipment that runs on fossil fuel—cars and trucks, city buses, industrial furnaces, etc.—would run on electricity.

It is true that nuclear is not the only low- or zero-carbon fuel. There is also wind, solar, wave/tidal, and micro hydro (a.k.a. run-of-river). I do not believe that any of these, or even all in combination, can be a reasonable substitute for nuclear.

Here’s why.

Let’s take wind, a commonly suggested form of generation. No one disagrees that wind is part of the answer; it just depends on what you mean by part.

Some people have suggested that wind could replace some of the 6,400 megawatts of coal-fired capacity the provincial government is trying to phase out. Let’s start with the world heavyweight champion of emitters, the 8-unit Nanticoke coal-fired station in Haldimand County on Lake Erie. Nanticoke’s capacity is just under 4,000 megawatts. Let’s say we want to replace this capacity with 1.5-mw wind turbines.

To replace Nanticoke’s nameplate capacity with 1.5-mw wind turbines, we would have to build over 2,600 of them. That’s a lot of windmills.

But everybody knows that it is meaningless to compare wind with fossil generation on the basis of nameplate capacity (that’s why the term is in italics). Fossil generation’s real value is in its flexibility and reliability: when you need power, you fire up the generator. Wind really falters when you work in a performance metric called the capacity factor (CF). Wind’s CF in Ontario has been put at 30 percent: i.e., an average windmill will generate power at its nameplate capacity 30 percent of the time.

So to replace Nanticoke with wind, we’re not really looking at replacing capacity. We’re looking at replacing electricity output. Nanticoke’s output in 2003 (not its biggest year) was just over 20 billion kilowatt-hours. How many 1.5 megawatt windmills would we need in order to crank out 20 billion kWh in an average year? With a CF of 30 percent, we would need over 7,700 of them.

The blade diameter of a General Electric 1.5-mw wind turbine is an average of 10 metres greater than the wing span of a Boeing 747-400ER freighter. Take 7,700 of these massive airplanes, put them up on poles, and you get an idea of what we’re talking about.

Where would we put all these machines? How many communities would be opposed to them? To answer this question, consider how many communities would be opposed to nuclear or gas-fired generating plants, or transmission-line routing. Take that number and multiply it by hundreds or even thousands. That is how many NIMBY (Not In My Back Yard) battles we would fight with communities that are opposed to wind farms and/or the transmission wires that connect them to the grid.

That’s not the only problem. What would the wires cost? And what would it cost to re-jig the transmission and distribution system to handle wind’s variability?

Forward thinking wind advocates see wind farms producing power for storage, in giant electrolyte batteries. Once charged, these batteries could provide a steady flow of power to the grid during peak periods (which these days are becoming less distinguishable from base load periods). Of course there is still recharge time, during which we would have to feed the grid with electricity from other generation sources. It is conceivable that such a scheme could work, but utility-scale power storage is way off in the future.

We need lots of base load power in either case. The numbers above show that it’s not coming from wind.

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