IN my recent little piece on light rail, I ventured the view that the ACT government’s initiative was driven, in part, by its feelings about climate change and perhaps a feeling that the day of “peak oil” had arrived.
Don Aitkin
Well, exaggeration aside, that suggests that we should be moving from cars to public transport, and from buses to light rail.
But of course the policy also goes on to talk about “reducing greenhouse gas emissions”, and there is a “plan” that projects that by 2020 the ACT will have reduced its greenhouse gas emissions very greatly, nearly 75 per cent of the reduction coming from smaller “energy supply sector emissions”.
If I understand all this correctly, what has happened is that the ACT Government has committed us to buying renewable energy (hydro and wind, mostly – solar hardly appears on any graph) to a high degree, and some time ago the then-minister told us that we were “on track” to have 90 per cent of our electricity from these sources by 2020.
Perhaps we are. But there’s some real uncertainty in all of this. Electricity comes from the grid (the National Energy Market), and the NEM is one of the largest grids in the world. About 70 per cent of the electricity is produced through coal-fired power stations, and the proportion is not likely to be much less in 2020. Renewables are increasing very slowly, and most of the recent increase is from hydro power.
So how can the ACT have reduced its greenhouse gas emissions when 70 per cent of the electricity comes from coal? Ah, well, we will have added to the renewable energy base by commissioning new solar and wind power, and that will offset our continuing use of coal-fired power, and then there are all those roof-top solar panels.
That’s a bit on the tortuous side, I think, and it comes with an additional problem. Wind power is not available when there’s no wind, and solar power is not available at night. Solar is getting more and more efficient, but we have not learned yet how to store large amounts of solar energy.
So we simply have to use fossil fuels to generate the electricity, not just to run the light rail at night and when there’s no wind, but to allow us to do all the other things we take for granted through flicking a switch.
There’s more. The flow of renewable energy into grids disturbs the even matching supply to demand that the grid managers have to ensure. The passage of clouds affects the generation of solar power, while the variation in wind speed affects wind-based energy.
In consequence, the grid managers have to ensure also that they have back-up to deal with those variations. Where does the back-up come from? Fossil fuels, usually gas, which is quick. (To bring on a coal-fired power station from a cold start takes a day.)
As I write, petrol is two thirds of the price it was only a few months ago, and the trend is downwards. No doubt the price will go up again, but it’s not obvious that “peak oil” has arrived. And while petrol is cheap, the poorer members of our community are happier, and the rationale for shifting transport on to electricity becomes less powerful.
I’m still persuaded that the move to light rail is justifiable, but not because it’s going to reduce greenhouse gas emissions. In fact, the less said about that by the ACT government and its Ministers, the better, even though it makes lots of Canberrans feel good.
Prof Don Aitkin, a former vice-chancellor of the University of Canberra, blogs at donaitkin.com
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