18 January 2018

Emissions claims about microwave ovens are a lot of hot air


The world was rather surprised to find out today that microwave ovens create carbon dioxide emissions. It could be that those in the UK are equivalent to 1.3 million cars, those across the EU to 7 million. There are is a useful point to be picked up from this little calculation and one rather large blind spot in it.

Of course, the numbers themselves are cooked. What is being compared is the total lifecycle emissions of the ovens as against those purely from use of cars. Rather a boiled veg to salad comparison. But on to the useful point.

Microwave ovens themselves of course have no emissions, not as they’re being used. At least, no carbon as such, even if we make damn sure the door’s closed because of the microwaves. The calculation of total lifecycle emissions comes from two other things; the electricity generation method used to power them, and the energy used to make them. Which is where we do begin to get somewhere in our work on total emissions.

For, obviously, we should be making the same calculations about electric cars, electric trains and, in fact, about everything else we produce. Those Teslas may not have any emissions from the tailpipes, but what’s the level of emissions from the electricity generation system that provides the juice? And manufacturing – what are the emissions from the construction of a large battery pack that must be, if not remade anew, at least remanufactured every few years?

Such total lifecycle calculations are controversial of course, for they require peering down into so many layers into the economy that it puts the kibosh on being able to plan. How far do we go looking into something as chaotic as an economy?

We’ve no real evidence that electric cars have fewer emissions than internal combustion ones and at least some methods of calculation insisting they have more. We need to go further than this, too. Do solar cells produce more energy than they take to make? I would argue the answer there is probably yes (I don’t know for certain, but am just looking at prices as a guide), although I’m a great deal less sure about windmills over their life.

For when we do go further we find some odd results – the Swansea Barrage being an example. It’s entirely true that it will make us all poorer, we know that from the cost-benefit analysis. But it’s also true that purely from a carbon budget point of view it’s not emission-free. Concrete, after all, produces some eight per cent of total emissions. Nuclear power generation also uses rather a lot of cement.

So if we really are going to worry over emissions we need to look at lifetime emissions for everything. Including, of course, those things which the general conversation insists are emission-free – something that nothing at all is.

But there’s also that blind spot in this calculation – here we reach, as all economists should, for our Bastiat. We need to look at what is unseen; in this instance, what would emissions be without microwave ovens? We could, of course, just declare that hot food, even cooked by microwave, is so neoliberal that we’d be better off without it. A difficult argument, given the theory that it’s cooking which led to Homo sapiens sapiens – the greater ease of digesting cooked food being what allows us to power our brains. (There are even rumours that some of us continue to use them.)

Leaving that aside, what would emissions be if we went back to less efficient electric ovens? Gas? Coal? Wood? Open fires? The answer, of course, is that emissions would be very much higher. That is because microwave ovens don’t have net positive emissions at all; even on this analysis of their lifecycle, they have net negative emissions – supposedly, the very thing we’re trying to achieve. It’s worth noting that we’ve not a great deal of proof of the same claim for supposedly world-saving technologies like electric cars, solar and wind turbines.

Note that this isn’t an argument about whether climate change exists, whether emissions cause it, nor about whether human beings do. It’s one about what our options are if all three of those claims were true. The two technical answers being, first, that only lifetime emissions are a useful guide, so we should be measuring those for everything, not just some domestic appliance that will get the story into the papers. And further, that the only useful measure is “compared to what?”

It is relative emissions compared to other ways of gaining civilisation that matter, assuming that civilisation is something we want to retain. That then leads to a policy insistence. For we cannot measure the lifetime emissions of everything down all the layers of the economy. Hayek’s Nobel lecture tells us that for, while he was talking about economic planning more generally, we still face the same “pretence of knowledge” problem.

The only method we’ve got of either planning or calculating something as complex as an economy is that economy itself. Thus we’ve got to use the one and only method we’ve got. One intervention into prices – that carbon tax – leaves all 7 billion of us to change our behaviour in the light of those new prices, incentives and knowledge. As Nick Stern, and every other economist, has been telling us for some decades now.

Tim Worstall is senior fellow at the Adam Smith Institute.