Post by David Walters on Jun 1, 2012 1:41:38 GMT 9.5
This was on the Green Left list in Austriala. Comments and replies please:
Discussion: Renewable Energy - a false hope?
History's first-ever 26-hour day.
True, the other side in this debate doesn't always have a good handle on the metrics either. Talking about "X gigawatts of solar power per hour" is the same thing as talking about "X horsepower per hour".
Meanwhile, some points of more consequence.
At its height, the proportion of German demand that was being met by solar on the day in question was close to 50 per cent. I suspect that would have been on a warm sunny day when air conditioners were being turned to their "cooling" cycle and demand was fairly robust (this effect is much more marked in hot countries such as Australia). Because of the solar capacity, it wouldn't have been necessary to turn on relatively inefficient, greenhouse-polluting "peaking" gas turbines to supply the strong demand.
The extra gas-fired capacity that was left turned off would have been expensive, probably costing multiples of the average wholesale electricity price. Meanwhile solar power, costing zero for fuel, comes essentially for nothing once the savings it produces have paid off the installation costs. The result, after a few years with large-scale solar, is that total energy spending on otherwise expensive power days can be decapitated.
A similar effect is being felt with wind power during peak demand periods here in South Australia.
Close to 50 per cent... and the grid didn't crash? We used to be told that anything above about 30 per cent feed-in from intermittent, non-baseload renewables was impossible to adjust for. The Germans seem to be managing it. True, they would have been exporting and importing electricity to and from other parts of the European grid. But much the same happens routinely in Australia too.
The cross-border power deals would have allowed peaking gas capacity in various countries to stay turned off.
Another point - it may well have been that the warm sunny day in Germany was relatively still, and not much wind power was being generated. But before long, the clouds would have moved over, the wind would have picked up, and Germany would again have been as I mostly remember it. No matter - the wind turbines would have spun faster, supplying renewable energy from another source. Wind and solar have an impressive tendency to complement each other, keeping the overall contribution from renewables high.
In South Australia, it's just been announced, wind power supplied 31 per cent of our electrical energy last year, and solar another 4-5 per cent. Our demand here is extremely "peaky", but the big peaks coincide with hot, bright summer afternoons when solar installations are going gangbusters. The more solar we install, the more the peaking gas turbines can stay switched off. And if we go for concentrating solar thermal with molten-salt storage, solar and wind between them will mostly look after the lesser demand peaks on winter evenings. Port Augusta, you'll find, is a great place to get sunburnt in July.
Haven't I forgotten those big high-pressure cells that can sit for days over south-eastern Australia, keeping winds light everywhere from the Hunter Valley to Tasmania and the Great Australian Bight? If your wind farms are concentrated in south-eastern Australia, you have a problem. But when the weather pattern is like this, the high-pressure cell directs a south-easterly airstream over points further north, bringing constant, relatively strong winds to places like the northern tablelands of NSW and the Queensland coast. The need is to build wind farms in these areas to provide balance.
Another thing I've just found out - average capacity utilisation of Australian wind farms, at about 34 per cent, is twice that in Germany. The wind farm at Gunning in NSW has a phenomenal capacity utilisation factor of over 40 per cent, and the big farm at Hallett in South Australia is just behind.
Go nuclear? You'd be daft.
Renfrey
Discussion: Renewable Energy - a false hope?
History's first-ever 26-hour day.
True, the other side in this debate doesn't always have a good handle on the metrics either. Talking about "X gigawatts of solar power per hour" is the same thing as talking about "X horsepower per hour".
Meanwhile, some points of more consequence.
At its height, the proportion of German demand that was being met by solar on the day in question was close to 50 per cent. I suspect that would have been on a warm sunny day when air conditioners were being turned to their "cooling" cycle and demand was fairly robust (this effect is much more marked in hot countries such as Australia). Because of the solar capacity, it wouldn't have been necessary to turn on relatively inefficient, greenhouse-polluting "peaking" gas turbines to supply the strong demand.
The extra gas-fired capacity that was left turned off would have been expensive, probably costing multiples of the average wholesale electricity price. Meanwhile solar power, costing zero for fuel, comes essentially for nothing once the savings it produces have paid off the installation costs. The result, after a few years with large-scale solar, is that total energy spending on otherwise expensive power days can be decapitated.
A similar effect is being felt with wind power during peak demand periods here in South Australia.
Close to 50 per cent... and the grid didn't crash? We used to be told that anything above about 30 per cent feed-in from intermittent, non-baseload renewables was impossible to adjust for. The Germans seem to be managing it. True, they would have been exporting and importing electricity to and from other parts of the European grid. But much the same happens routinely in Australia too.
The cross-border power deals would have allowed peaking gas capacity in various countries to stay turned off.
Another point - it may well have been that the warm sunny day in Germany was relatively still, and not much wind power was being generated. But before long, the clouds would have moved over, the wind would have picked up, and Germany would again have been as I mostly remember it. No matter - the wind turbines would have spun faster, supplying renewable energy from another source. Wind and solar have an impressive tendency to complement each other, keeping the overall contribution from renewables high.
In South Australia, it's just been announced, wind power supplied 31 per cent of our electrical energy last year, and solar another 4-5 per cent. Our demand here is extremely "peaky", but the big peaks coincide with hot, bright summer afternoons when solar installations are going gangbusters. The more solar we install, the more the peaking gas turbines can stay switched off. And if we go for concentrating solar thermal with molten-salt storage, solar and wind between them will mostly look after the lesser demand peaks on winter evenings. Port Augusta, you'll find, is a great place to get sunburnt in July.
Haven't I forgotten those big high-pressure cells that can sit for days over south-eastern Australia, keeping winds light everywhere from the Hunter Valley to Tasmania and the Great Australian Bight? If your wind farms are concentrated in south-eastern Australia, you have a problem. But when the weather pattern is like this, the high-pressure cell directs a south-easterly airstream over points further north, bringing constant, relatively strong winds to places like the northern tablelands of NSW and the Queensland coast. The need is to build wind farms in these areas to provide balance.
Another thing I've just found out - average capacity utilisation of Australian wind farms, at about 34 per cent, is twice that in Germany. The wind farm at Gunning in NSW has a phenomenal capacity utilisation factor of over 40 per cent, and the big farm at Hallett in South Australia is just behind.
Go nuclear? You'd be daft.
Renfrey
