The powers that be in Ontario (McGuinty, the Premier, and Duguid, the Minister of Energy) have prominently mentioned that getting rid of coal is the prime benefit to installing all the wind turbines. One thing missing from their statements is any mention of how much coal is actually saved by installing wind. In an earlier posting I dug into the numbers behind a couple of exceptionally good days for wind energy production and discovered all that wind energy didn’t translate noticeably to a reduction in coal consumption, let alone a reduction in emissions (a topic I covered in another earlier posting as well. But it struck me that maybe sampling 3 days wasn’t really fair; that maybe I ought to take a look at an entire month. So I took a look at the actual operating experience in the last full month – November 2010 – and while an argument could be made that coal consumption was reduced, it was so small as to disappear into the noise.
The Ontario system operator (the IESO) is very good at providing operational data to the public. One of their products is the hourly output of all their generating plants. I collected these values into a spreadsheet (which is available, just ask) and then plotted wind generation vs. coal generation on a daily basis. The thought was that as wind increases coal should decrease and maybe over the period of a month I could see the trend. I then pulled out the weekends, as the demand then is so much lower that it would be a confounding variable. I sorted the remaining 22 days by wind production, and then graphed the wind and coal production numbers. What I’d liked to have seen are two crossed lines, with the wind going up while the coal comes down. What I got is shown below.
The daily wind production varied from a low of about 1000MW-hr to a very respectable 26000MW-hr, and is shown in magenta. The corresponding coal production is shown in blue, and varied from a low of 7000MW-hr to a high of 25000. As you can see, the coal production varies widely, and is not particularly related to wind production. However, there is a slight downward trend to coal production with rising wind, as shown by the black line. A proponent would look at the black line and claim victory.
But is it really a victory and if so, how much of one? The first problem with the numbers is the relatively shallow slope of the coal line compared with the large variability of the daily coal numbers. The r-squared value for the line is 0.02, which is to say that the black line explains almost none of the behaviour of the underlying numbers. For a comparison, the Hoen report that claimed that wind projects do not affect property values had r-squared values in the 0.75 range, and he still considered that insufficient.
But let us assume that the black line is in fact shaped the way it is exclusively due to the wind generation – a very generous assumption. The roughly 11,000MW-hr of average daily wind production ended up saving (looking at the extreme ends of the black line) about 2000MW-hr of coal production, only about 18%. November was a very good month for wind production so that is probably close to the highest number Ontario might attain. As the capacity factor of wind on those days averaged 28%, the final wind capacity-to-coal savings is about 5%.
To state this another way, assuming wind and coal are related at all (and that’s an iffy assumption), it takes 20MW of wind capacity to offset 1MW of coal generation. Ontario’s 1200MW of wind capacity at best leads to a whopping 60MW reduction of coal generation, about 15% of one typical coal generator (of which Nanticoke has 8).
As miserable as these best-case numbers are, they almost certainly don’t lead to any emissions reductions.
Just the financial cost of these wind turbines compared to the benefit staggers the conscience, not to mention the costs to the environment and the neighbors. A bad deal all around.
Update, December 23, 2010. I ran some more numbers and the ineffectiveness conclusion is now even stronger.