Wednesday, May 09, 2007

Is district energy environment-friendly? It depends on what fuel and which province
A few years ago, I helped do a study on the possibilities of carbon monoxide infiltration through fresh air intakes at a Canadian government building complex in Ottawa. What was the source of the CO? The exhaust port from the gas-fired furnace at the central heating plant at the complex. After an extensive wind-tunnel simulation, we concluded that the probability of significant CO infiltration was minimal.


The heating plant is one of ten similar government-run plants in the national capital area. Nine of the plants are on the Ontario side of the Ottawa River; one is on Sacré-Coeur Boulevard in Gatineau, Quebec.

Many of these plants are linked together in what’s known as a district heating system: a network of pipes that distribute steam and sometimes cold water to individual buildings along the network.

The Sacré-Coeur heating plant has a number of furnaces, including some that are electric-powered. A few years ago, in an effort to promote clean Quebec electricity, Hydro-Quebec, the provincial utility and the biggest power generator in Canada, installed the electric units at the plant. Of course, the deal also included a power purchase agreement with Hydro-Quebec.

Then, in a bizarre twist, Hydro found an electricity buyer willing to pay more than the feds. And it must have been much more, because the utility asked the feds not to run the units at all except as backup. The feds didn’t like these terms and decided to mothball the units. Hydro has since removed the electrical connection altogether, and the Sacré-Coeur plant creates heat solely with fossil fuel.

District heating is touted as efficient and environment friendly, and in principle this sounds like a fair claim. But it is unwise to generalize. Generating heat with gas at the Sacré-Coeur plant produces nearly 25 times more greenhouse gases (GHGs) than generating it with Quebec electricity. And that’s assuming the gas-fired units are highly efficient.

Anyone looking to create a district heating system in Quebec, Newfoundland-Labrador, Manitoba, or British Columbia should take this into account—especially if climate change and clean air are important project considerations. Electric heat in these provinces produces 6–25 times less GHGs than natural gas (see Environment Canada’s Electricity Intensity tables).

And in Ontario, GHGs per BTUH of electric-generated heat are now slightly less than those of high-efficiency gas. As more nuclear units come on line, Ontario electricity will become much less emission intensive.

Needless to say, electric heat is also far cleaner with respect to bona fide pollutants, like the CO in the study I mentioned at the beginning. Had that building complex been heated with electricity, there would have been no issue with CO from heating exhaust.

Federal and provincial energy policymakers should take this into account.


(Note: I hope to see you all at the Canadian District Energy Association’s conference in Toronto on June 13–15. For more info, see www.cdea.ca.)

1 Comments:

Blogger Randal Leavitt said...

Put the new reactor underneath Confederation Square. The heat coming off the turbine could warm half the city - clean and free. It does not get much better than that. Why don't we do it? Because everyone flunked out in high school physics. Ignorance is expensive.

6:42 PM  

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