https://www.bbc.com/news/business-51852637
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Coal power developers risk wasting hundreds of billions of pounds as new renewable sources are now cheaper than new coal plants, a report has said.
The shift is mainly down to the tumbling cost of wind and solar power, researchers from Carbon Tracker said.
They added that in 10 years it will be cheaper to close down coal plants and build wind and solar plants instead.
But the International Energy Agency (IEA) says coal will remain the largest global power source for years.
The report's authors say they looked at the economics of 95% of the world's coal-fired power stations.
In most countries, including the UK, it's already cheaper to build renewable energy generation than new coal-burning plants.
At 60% of coal plants in the world, the generating costs are higher than they would be from new renewables, the report said.
But the study goes a step further, forecasting that within 10 years the cheapest option in all countries would be to close down existing coal-fired power stations and build wind and solar power plants instead.
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They are not interchangeable. A coal plant produces power when it's needed; A wind or solar plant produces power when it's possible to do so.
The appropriate comparison is not between the cost of coal generation and that of wind or solar generation; It's between the cost of coal generation and the cost of wind or solar
plus the necessary storage to provide the same amount of 24x7 power as the coal plant.
To replace 1GW of coal power, you need about 0.8GW of nuclear power; Or about 3GW of wind power plus at least 250GWh of storage, capable of charging at 2 or 3GW, and discharging at 1GW, and of switching rapidly between these states. And a place where wind power generation never falls below the median generation rate for more than a week.
That storage is not just expensive; it's so expensive that it's completely unachievable with current technology - there's not enough lithium for all the batteries you would need, nor enough suitable sites for hydro storage, nor the infrastructure needed to hook such massive storage up to the generation technology.
Handwaving away this problem is the only reason why anyone thinks wind or solar are a plausible replacement for coal. But they are simply not.
It's
possible (though hideously expensive) to install storage on a domestic level, as long as you don't mind at least some blackouts - how many and how often you can tolerate a blackout determines the cost, which increases exponentially as your tolerance for being without power falls away.
But domestic power consumption is a tiny part of the total. Industry and commerce require reliable power - and lots of it.
It's one thing to accept having to occasionally chuck out spoiled food from your home refrigerator; But it's quite another to envisage the local supermarket and their warehouse having to do the same - and just at the time when demand for that food peaks (because of all the domestic spoilage). And I don't see any Wall Street banks liking the idea that their trading day could be interrupted because the batteries are flat, and it's calm and cloudy.
The economics of intermittent power generation, with the intermittency outside our control, are impossible to make work, no matter how cheap the generators become. Intermittent power isn't a commodity that has a market. The market is for power on demand.
Intermittent power
plus storage might, perhaps, one day be viable. But right now, we get intermittent power
plus gas*. Which isn't a solution to climate change at all.
* Often hidden as 'other' or 'imports' - hint: gas power plants in neighbouring states or countries are still adding CO2 to the atmosphere, even if you hide that fact behind the description 'imports' in your reporting
