2050 calculator: the limits of arithmetic exposed

Regular readers will be aware of Prof David Mackay and his book Sustainability Without the Hot Air, which was published to rave reviews at 2008. It's also available free online as a pdf.

In it, he runs through the numbers needed to get the UK off fossil fuel and in one chapter (27) he outlines five different plans which would enable us to do this. Now, David is very careful not to stick his neck out on a limb here and say which one he thinks is best, but it's hard not to conclude that his money is on Plan E, the nuclear option. He has already given nuclear a big thumbs up (in Ch 24) and in Ch 27 he prefaces Plan E by stating:

E stands for “economics.” This fifth plan is a rough guess for what might
happen in a liberated energy market with a strong carbon price. On a level
economic playing field with a strong price signal preventing the emission
of CO2, we don’t expect a diverse solution with a wide range of power-
costs; rather, we expect an economically optimal solution that delivers the
required power at the lowest cost. And when “clean coal” and nuclear go
head to head on price, it’s nuclear that wins.


In other words, the nuclear option is safe, clean and the cheapest option of the five presented. What's not to like? If Apple produced an iNuke, we'd be lapping them up. But Apple don't do nukes, and there is a certain amount of consumer resistance here, especially in Germany and Japan.

Fast forward three years and David Mackay finds himself the Chief Scientist at the Department for Energy and Climate Change, in charge of a project called the 2050 Pathways Calculator which is used to inform the government's Carbon Plan for the years between now and 2050 when (the plan is) to reduce our CO2 emissions by 80%.

Now the 2050 Pathways Calculator is based on a vast Excel spreadsheet and consequently it's very difficult to comprehend, especially as its populated by so much interactive data. But at heart its mission remains very similar to what was set out in Ch 27 of David's book - namely to come up with some plans or pathways to get the UK off fossil fuels by 2050.

The front-end of the calculator (i.e. the bit we see) is not that difficult to comprehend. The choices are split into two parts: firstly, how to decrease demand (for all energy) and, secondly, how to increase supply of low-carbon energy. We are invited to take control and see how we would pilot the mothership.

Twiddling the controls, it quickly becomes apparent that we can't do this by demand reduction alone. Our legacy infrastructure is so wasteful of energy that it's inconceivable that we can bring about an 80% reduction in the amount of energy we consume in the UK, especially as these models take for granted that we still have economic growth at around 2% per annum and a rising population.

After much gnashing of teeth, it becomes apparent that about the best thing we can do on the demand side is to switch everything as we can think of over to electricity. So houses should switch to heat pumps, cars to batteries and industrial processes to anything but fossil fuels. Insulation and behaviour change help a bit, but they are basically second order effects — insignificant in the great scheme of things.

Which leads us onto part 2 of the calculation, the supply side, or how the hell are we going to create all this low carbon electricity. The calculator permits you to choose four options for each technology. In each case Option 1 is basically do nothing and Option 4 is the Max Out button. You can jiggle and you can jaggle and you can find dozens of ways of producing enough juice to get the overall CO2 emissions down by 80%, provided you have done some demand reduction and you add it a little biofuel. There is something for everyone here and the green pressure groups are delighted because it shows (once and for all) that we can get there without a drop of nuclear energy, which is now the German option.

But of course, we are still faced with the economic logic of David Mackay's Plan E. Surely, when all is said and done, Plan E, the nuclear option will be the cheapest?

Well you wouldn't know it to behold the latest version of the 2050 Calculator which now has costs attached to it. It's still in beta, but it's available online, complete with some sample pathways to check out. The closest option to Plan E is the one labelled Higher Nuclear, Less Energy Efficiency, although why these two should be paired isn't explained. The point is that's it's not the cheapest option and even if you tweak it so it's higher nuclear plus lots of energy efficiency, it's still more expensive than the best in class, which is known as Markal 3.26 (don't ask!).

Markal 3.26 is as bit of a mish-mash, using a bit of everything including carbon capture and storage, lots of wind, some waves, some biofuel, and a bit of nuclear. In other words, almost exactly what David himself had warned us wouldn't be the cheapest option when he introduced Plan E in his book (see the quote in italics above). History tells us that when there is a race to develop competing technologies to carry out the same task, then pretty quickly one wins out. But the 2050 Calculator is sitting on the fence, not picking a winner or even indicating what the cheapest option might be.

Now buried deep inside this version of the Calculator is a wiki which lists all of the cost assumptions used to make the latest version. The project boasts of being open source and anyone can come along and edit the wiki, which sounds like a great idea. Except that hardly anyone has bothered (few seem to know of its existence) so that around 98% of the entries are from the DECC staff members charged with populating the calculator with data.

Dig around the wiki and you'll find an interesting item called the Worry List and on the list is an interesting item called Are We Going To Try And Answer The Really Big Questions:

• What is the cheapest pathway?
• Is it cheaper / how much more expensive is it to tackle climate change than to not?
• What are the biggest costs in tackling climate change?
• What are the biggest sources of uncertainty in tackling climate change?
• Is it cheaper to be more energy efficient or to build more capacity?
• Is nuclear cheaper than wind or CCS?

In theory, the costed version of the Calculator should answer all these questions but in practice the various pathways turn out to be very similar cost-wise, even the cost of doing nothing at all about climate mitigation. Which has surprised some right-wing commentators (cf Worstall, Booker). And it also surprised me. I was expecting a clear winner, not a photo-finish.

It's at this point that I begin to suspect that politics may be overriding arithmetic, and that the 2050 calculator has been tweaked to give the answers that the government wants to hear — i.e. that it's on the right track, and that what it proposes in its Carbon Plan is the best way forward. Far from challenging conventional wisdom on sustainable energy, the Calculator results seem to re-infoce it.

I wonder what David Mackay thinks? Has his baby been hijacked by political expediency? Or were his original back-of-the-envelope style calculations simply wrong? Because what has emerged from the 2050 calculator exercise looks very different to what he set out in Chapter 27 of his book.