By Michael Le Page
Could solar farms provide our food?
Blickwinkel/Alamy Stock Photo
It is being claimed we could save the planet by turning renewable energy directly into food and rewilding all the farmland that is no longer needed. Could it really work?
In a Guardian column and a TV documentary called Apocalypse Cow, environmentalist and journalist George Monbiot says food grown in vats using renewable energy could transform food production.
He highlights a Finnish company called Solar Foods, which makes food from air. It feeds bacteria hydrogen, providing energy the bacteria use to turn carbon dioxide and nitrogen in air into protein-rich organic matter.
The land efficiency, the company estimates, is roughly 20,000 times greater, Monbiot writes. Everyone on Earth could be handsomely fed, and using a tiny fraction of its surface.
Monbiot is absolutely right about the destructiveness of food production – but his numbers are off.
The head of Solar Foods, Pasi Vainikka, tells me that the efficiency figure Monbiot cites applies only to the area of land taken up the factories. If the energy was derived from solar, Vainikka says, then it would be only ten times more land efficient than farmed soya.
Sadly, this suggests Monbiots claim in 2018 that all the protein the world now eats could be cultivated in an area smaller than Ohio is rather wide of the mark.
But we do need to do something about the impact of our food and even a small reduction in farmland could make a big difference. Habitat loss is the single biggest killer of wildlife, for instance, and its largely due to farming.
Farming and land clearance also produces a third of all greenhouse gas emissions. And organic farming is even worse than conventional farming.
Food production is also not very efficient. Almost all the food we eat derives from photosynthesis. This will be true for lab-grown meat as well, if fed nutrients obtained from plants.
Less than 0.5 per cent of the light energy falling on a field gets turned into food. By contrast, solar panels convert around 17 per cent of the light energy falling on them into electricity.
Solar Foods says it can convert electricity into food – via hydrogen – with an efficiency of 20 per cent. Thats several times better than photosynthesis.
It is technically feasible. In fact, a company called Calysta is already producing animal feed from microbes fed on methane – but the methane comes from natural gas.
Solar Foods says its process is economically feasible, too, and that it will be able beat the price of soya, the cheapest protein widely used for animal feed.
But there are other issues. There are grand plans for using hydrogen for everything from heating homes to powering aeroplanes. But we dont produce enough hydrogen for this, and 99 per cent of it is made from fossil fuels, so using it wont reduce emissions.
We don’t have renewable electricity to spare, and half of the energy is lost when making hydrogen. So clean hydrogen is a limited resource and should be used wisely.
Using huge amounts of renewable energy to produce hydrogen to make farm-free food could thus undercut other efforts to cut limit climate change – the other great threat to wildlife.
However, it would also eliminate greenhouse emissions and other forms of pollution from the farms that are replaced, so it might still be a win overall.
The bottom line is that it is still far from clear if farm-free foods can save the planet. But the potential rewards are so immense that that we should be pouring vast sums of money into finding out.
And in the meantime, we should do all we can to minimise the land needed for farming, such as eating less meat, stopping turning foods like palm oil into biofuels and embracing genetically modified supercrops.
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By Michael Le Page