Monday, April 2, 2012

Renewables and the Grid

Here in BC, we are blessed with a steady supply of hydro-electricity. Water is a renewable resource, and so this electricity is almost endless in its supply and generates very few greenhouse gases. There are not many places on the planet as lucky as us. Most places in the world have to use non-renewable resources to generate their electricity.

In addition, dams are very useful as energy storage. They are by far the cheapest type of "batteries" there are, waaay cheaper than electrochemical batteries! It may surprise you to learn that BCHydro is already in effect selling storage to other jurisdictions. BC takes electricity in from Alberta's windfarms when they are generating too much. Because you can't "turn off" a coal-fired electricity plant, Alberta  has no choice but to "dump" wind-generated electricity at times of high wind. It is forced to sell it cheap to BC; we run our dams a little less to compensate. The net effect is then that wind power is displacing hydro power, and not dirty coal...and that BC makes money at the expense of AB. It means that BCHydro is not actually importing "dirty" power from AB, but preferentially clean power from wind...

The same type of thing happens between Norway and Denmark. Denmark has a lot of wind power, but also a vast network of coal-fired heat/electricity co-generation plants. These are distributed and locally-based. They are quite efficient, and the waste heat they generate is used to heat to local homes. This is great, but the downside is that they can't be turned off without people getting cold! So when the wind blows hard in Denmark, they actually give away electricity to Norway. Norway "stores" it in their dams. The result for Denmark is that they pay quite high prices for their electricity, and they haven't shut a single coal plant down. Meanwhile, Norway is getting economic benefit.

The Bonneville Power Authority south of us in WA and OR has similar problems. They have a really mixed setup with one nuclear power station, a coal-plant, a big hydro system, and lots of wind farms. But when a spring melt coincides with spring winds, they have to shut their windfarms down (resulting in financial losses to the windfarm operators)! This is because you can't turn off a coal- or nuclear-based plant - they are designed to run at a constant "baseload" level - and you can't totally block a hydro dam either. It dries the river and kills the fish. Nor can you just open the dam totally, because the high level of turbulence which then results will also kill the fish. So the choice becomes "kill the fish" or "turn off the windfarm". Rather unexpected, eh?

This is not a problem that a "smart grid" or "distributed power sources" is going to solve. Denmark already has distributed power. The reason that Alberta doesn't have to actually turn off its windfarms is because there is a "smart grid" in place and BC can take their excess power.

For most countries, designing an electrical grid that provides:
1. renewable power
2. cheap power
3. constant power
simultaneously, is not possible. You can pick any 2 of these, but not all three at once.

For a while, BC was in happyland, where we did have all three requirements being fulfilled. But those days are coming to an end.

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