Honouring David MacKay’s contribution to the future of energy: “being pro-arithmetic”

Bert Hubert
Apr 16, 2016 · 5 min read

This week, one of my heroes died a highly untimely death. David MacKay was a physicist and a professor of engineering at Cambridge. In addition to his notable contributions to information theory, which can be found in 10Gbit/s ethernet, our fastest cable modems and space communications, he contributed vastly to the state of machine learning and wrote (& funded the first release of) a monumental book on sustainable energy. He also believed in public service so his books are available free of charge under a permissive license.

In this post I want to honour and perpetuate his work on delivering the real, rational, story of how we use energy and how we could (not) generate it sustainably. Because sadly, this is going to be far harder than optimistic articles and politicians would have us believe.

The book “Sustainable Energywithout the hot air is the successful attempt to “cut the emissions of twaddle about sustainable energy” (paraphrased). “Everyone says getting off fossil fuels is important, and we’re all encouraged to ‘make a difference’, but many of the things that allegedly make a difference don’t add up.”

And a few paragraphs later: “Numbers are chosen to impress, to score points in arguments, rather than to inform… we are inundated with a flood of crazy innumerate codswallop.”

Rather than give yet another summary of his great book, I will restrict myself to some of the boldest realities that David MacKay worked so hard to get understood.

There is no palatable plan at all for getting to sustainable energy

Remember CFCs and the ozone layer? That was an intervention that worked. Some countries dragged their feet, some industries claimed they were special, but under sufficient pressure everyone caved. A similar thing happened to phosphates in detergents. This was something that could be achieved if only people cared enough. It made sense to protest and lament politicians and governments that were slow to act. Because there was an alternative.

You might get this same feeling over renewables: we set goals, we pressure people to use more ‘green’ energy, appoint a Chief Sustainability Officer, lower some carbon emissions, install more solar panels, put up some more windmills. You might get the impression that all we need to do is follow through and get on with it.

But it ain’t so. Even semi-realistic plans involve several of:

  • halving our energy use by using public transport for everything
  • building hundreds of nuclear power plants (per big country)
  • hundreds of thousands of windmills (per big country)
  • filling double digit percentages of our countryside with energy crops and solar panels;
  • or doing so in other countries so we get their renewable energy.

It is going to hurt tremendously, and the steps we are taking now are not going to get us there.

But how can that be when we some countries appear to be making such great progress?

We see lovely photos of windfarms in Denmark with headlines like “Wind power generates 140% of Denmark’s electricity demand” and quotes to match: “It shows that a world powered 100% by renewable energy is no fantasy”.

But it is a fantasy — unless you fundamentally overhaul that world in ways no politician wants to talk about.

Energy is far more than electricity.

Next time you read such a “140%” claim, know that electricity makes up 20–30% of our energy needs. It is wonderful that on one day Denmark had a 40% electricity surplus but on that same day they still used much more energy from oil, gas and coal for other things. Like driving cars, flying planes and heating buildings. Judge claims on how they solve energy demand and not electricity generation!

The headline typically speaks about one good day

It sure is lovely to write a headline like “Half of Germany Is Now Powered by Solar Energy”. Even if we forgive them for confusing energy and electricity (again), this would only work for days with exceptionally cooperative weather. Compare this actual graph of where Germany’s electricity (not energy!) came from in August 2015:

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https://www.energy-charts.de/power.htm —source of German electricity in August 2015

Not one day did solar actually deliver half of all electricity, nor did it do so in any day in one of the surrounding summer months. Also, note how much uranium (nuclear!) there is in this graph!

We need a plan that allows the whole world to develop

Some countries are blessed with lots of wind, lots of sun or sometimes even both. Others have rivers flowing down mountains and they too can green themselves up. And that is great for them. Yet more countries could become self-sufficient because they currently use relatively little energy for their size. But we need a plan for the whole world!

This map shows you an optimistic take on things, and is again labeled as solving the world’s energy problem, while in fact it is only a very optimistic projection of how we could deliver sufficient electricity, which as we recall is a many times smaller problem.

To make this real, I’ve edited this map slightly. Each green square delivers the energy needs of one billion Europeans. So if we want to share our level of consumption with the rest of the world, we’d need 7 of those squares, each 600 by 600 kilometers. Oh, and displace anyone and anything living under them!

It is quite feasible for North African countries to create all the energy they currently need for themselves from solar. But it is not possible to do so for the whole world.

So is everything hopeless?

Not quite. But David MacKay spent years railing against those advocating doing little things, ignoring that lots of little things together do not achieve anything big. Unplugging your phone charger for a day saves as much energy as not driving your car for a second, for example.

Any solution will involve big things. Country sized solar farms, whole seas and coasts filled with windmills, severe restrictions on private transport and planeflight, astounding numbers of (expensive) nuclear or other advanced power plants.

Professor MacKay’s main goal was to bring back realism into our energy and climate discussions. To this end, I urge you to go read Sustainable Energy — without the hot air, or perhaps just the 10-page synopsis, and realize that we are up for a gigantic challenge that is not just a matter of getting politicians to see the light or holding ‘earth hour’ events. It is going to hurt, and we all need to know that doing little things is not going to save us.

I want to end this post with my favorite David MacKay quote:

“Please don’t get me wrong: I’m not trying to be pro-nuclear or anti-wind. I’m just pro-arithmetic”.

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