You hear a lot about how much it'll cost society to switch to clean energy. But these arguments nearly always ignore the cost of sticking to the fossil-fueled status quo, namely that because you're literally burning the stuff, you have to keep buying more forever.
Sure, repowering industrial society will cost a few quid, but how does that compare to all the money we'd spend on petrol and gas over the same period?
Until recently no-one knew, but the brilliant Chris Goodall has run the numbers and made a big discovery: it actually works out cheaper to go all-out for solar power.
He imagines two different futures: one where we keep getting most of our power from coal, oil and gas, and one where solar power keeps growing quickly, providing 100% of the world's energy (electricity, heating, transport – everything!) by 2041.
Even if you assume oil stays ridiculously cheap, solar power still comes out on top.
Of course, comparing future energy systems means guessing the future cost of different technologies, and the gods love to embarrass people who venture predictions like this. But Goodall has played it safe here, and been extra generous to fossil fuels. But even though he assumes the price of oil will stay ridiculously low, solar still comes out on top.
The 100% solar future doesn't assume any big breakthroughs either – just a continuation of the growth trends and price decreases that are already underway.
And when there's no sun?
If you're reading this on a chilly winter evening, it's hard to imagine how a 100% solar powered energy system could work.
Relying on solar panels alone, it'd definitely be a struggle, but luckily we've got other tools in the toolbox. We can use 'demand response' systems to match our electricity use to the daily peaks in solar power, and storage technology to cover the rest.
Of course, in the real world we wouldn't need to limit ourselves to solar, and the job gets easier when you bring other technologies into the mix: wind, wave and hydro power tends to do well when solar power is low, while tidal and geothermal energy are pretty consistent throughout the year.
A price worth paying
In some ways, this isn't a hugely important result – even if clean energy had come out more expensive, there'd still be an overwhelming argument for making the switch. Because climate change ruins everything, it's worth paying a lot to avoid it. But for as long as the cost argument is used to dismiss the clean energy switch as hippy idealism, it's worth having a comeback.
You can read Goodall's writeup and download the full paper here. And if you like smart, original analysis of big trends in climate and energy, you need Chris Goodall's newsletter in your life.