Greenhouse Canada

Features Energy Management
From the Editor: Greenhouse power plants

September 2, 2008  By Dave Harrison

Ontario politicians are having a
hard time resolving electricity generation problems. During peak
demands, the province is hard-pressed to meet demand.

Ontario politicians are having a hard time resolving electricity generation problems. During peak demands, the province is hard-pressed to meet demand.

And Ontario greenhouse growers could play a bigger role in the solution.


By way of background, the government has pledged to phase out coal-fired generating plants as its commitment to improving air quality. There are plans for more nuclear power, along with a few massive natural gas plants. These all take years to develop and have little prospect of coming in anywhere near budget.

What has been developing lately is a “Not-In-My-Backyard” (NIMBY) backlash to development of new large-scale generating plants in the province, especially if they happen to be proposed near residential areas. For example, the province has been trying to find a home for a new gas-fired electricity plant in or around the Toronto region, but with no luck. The proposal is for a 350-megawatt facility to serve the region.

Local residents want none of it.

What’s interesting is that much of the opposition, according to Toronto Star environment reporter Moira Welsh, is that the critics say the province is relying on inefficient technologies. Smaller, more efficient power plants are the answer, they say.

She explains there are three types of natural gas-powered plants.

The “simple single cycle” plant uses a gas turbine to power a generator. It’s estimated to convert 35 to 40 per cent of the energy in the natural gas into electricity.

The “combined-cycle” plant is a little more sophisticated. It takes the heat created by the generator to make steam, and this is used to make even more electricity. The efficiency rate is between 40 and 60 per cent.

The third option is a “combined heat and power” system, and this is where greenhouses could be utilized. These systems create electricity and steam, with the latter available for heating purposes to increase the efficiency rate to at least 80 per cent.

CHP units are fairly common in Europe. And in our June edition, we profiled the adoption of this technology by Great Northern Hydroponics in Leamington. The management team knew heating costs were getting out of hand, and began investigating alternatives. They looked at biomass and coal but weren’t convinced they are long-term solutions. “We had to determine what was sustainable, not just for our cost containment, but also for the environment,” said company president Darrin Didychuk. At the same time it’s generating up to 12 megawatts of electricity, the company can also utilize the heat and the carbon dioxide, both of which would be considered waste byproducts in traditional gas-fired electricity plants.

Thirty similar greenhouse projects would provide the same power the province is trying to develop in the Toronto region.

The ball is in the province’s court. This would help answer the energy needs of Ontario, and also be a major boost to the greenhouse sector. It’s a chance to squeeze the most out of energy supplies – by generating electricity, growing plants and eliminating carbon dioxide emissions. It’s a win-win-win proposal.

And with no objectors.

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