I take this to be exceedingly good news. Our struggles to contain climate change are entirely over and we can all go back to sleep:

Solar has won. Even if coal were free to burn, power stations couldn't compete

As early as 2018, solar could be economically viable to power big cities. By 2040 over half of all electricity may be generated in the same place it's used. Centralised, coal-fired power is over.

It's true that we don't normally believe The Guardian on matters environmental. But let us just take them seriously here.

As we all know the predictions of future climate change are based upon economic predictions of the future. How many people will there be, how rich will they be and what technologies will they be using to generate the power to create that wealth for that many people. And of the models that are used the one that tells us that we've a serious problem with climate change insists that we'll still be using coal for 50% of our power needs in 2080 or so.

We don't actually have to believe that in order to be able to observe that that is the central point of the alarmist case.

Excellent, so, if no one is going to be using coal in the future then we've not got a problem with climate change, do we?

Do note that this is not to take as being true, nor even seriously, any of the predictions that are being made by anyone. It is, rather, just to point out an important piece of logic. If solar is now, or will be imminently, cheaper than coal so that we all start to use it purely on economic grounds then the problems with climate change are over. For all of the models and predictions insist that we only get major problems if we don't stop using coal.

It cannot be true that solar is wholly (and unsubsidised) competitive, or cheaper, than coal and we still have a problem. Alternatively, it cannot be true that we still have a problem in hte future if we believe what we are being told about the imminent cost competitiveness of solar.

It's an either or thing.

Looking at the true numbers, rather than those provided by the boosters of solar power, it's probably a little early, 2018, to be saying that solar will be truly competitive. But by 2025 (as Bjorn Lomborg has long been saying) it almost certainly will be. Meaning that we don't actually have a problem and that we can indeed all go back to sleep.

The only way that this cannot be true is if solar doesn't become so competitive. In which case we shouldn't be working so hard to install it either, should we?