Monday, July 03, 2006

Alternatives in power.

Yesterday I visited the power turbines at the Huron Power wind farm in Bruce County. The wind farm is rated for a maximum output of 9 MW’s, (5 turbines x 1.8 MW per turbine). In 2005 the wind farm reached an overall capacity of approximately 24%. This would loosely equal a 19.0 GWh cumulative output total for the entire year. This is a good start. The wind farm is located in an area known as the Bruce Energy Centre. The main electricity producer in the Bruce Energy Centre is the Bruce nuclear power plant. Currently rated at 4.7 GW of output power the nuclear generators dwarf the output of the Huron Wind farm. To equal the output of the nuclear facility, Huron wind would need to open approximately 522 more wind farms of equal capacity to that of the existing wind farm, (522 x 5 = 2610 additional turbines). This seems impractical as well as very unlikely.

So what are our options?
Are more “nukes” the answer?

I’m not convinced that nuclear is the way to go. It could take up to 20 years before a new power plant is online, or even under construction. Then there is the question of efficiencies.
Nuclear power plants, much like coal and natural gas power plants, use huge amounts of energy to boil water and thus produce steam. The steam is “forced” into a turbine which is physically linked to an electric generator. The motion of steam across the blades of the turbine causes the fan to turn and thus the shaft connecting the turbine to the generator. The generator produces an electric current which is then sent into the “grid” for distribution. Cold water from a nearby water source cools the steam until it becomes a liquid again. Then this water is reheated until it boils and the process is repeated. Overall approximately 66% of the energy produced by this process is simply expelled as waste. The other 33% is transmitted into the electric grid for distribution. Now I know this is a very simplified version of what really happens but it might make you wonder why the water is heated and cooled repeatedly.

Isn’t that wasteful?
Can’t we do better than a mere 33% efficiency?


So what other options do we have?

Currently not many, no matter how much “tree hugging” we may want to do, wind and solar can’t even come close to meeting all of our current needs. We need to find a solution that, along with conservation, will fix the problem quickly.

One possible solution is to invest in a decentralised power system. By creating a network of smaller generating stations close to the electricity consumers, the inefficiencies of line loss can be minimised. But what about the inefficiencies of turning water into steam and back again? Part of the answer may lie in something called a Combined Cycle generator. Such a generator uses its own exhaust to power a second generator. The exhaust from the gas turbine is injected into a waste heat recovery boiler and the steam created by this process is fed into a steam turbine that is connected to a second generator. General Electric claims that the systems overall efficiency is approximately 60%.

This is already taking place right here in Ontario.
If only we could get one of these in our neighbourhood!

Check out these websites for more info.


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