sustainable energy without the hot air

sustainable energy without the hot air by david mackay – book review

(Sir) David Mackay’s ‘Sustainable Energy without the hot air’ is by far the best book I’ve read on this subject. It takes a fact-based approach to the problem, and comes to some, maybe not surprising but, challenging conclusions. It is the book equivalent of Al Gore’s ‘An Inconvenient Truth’ and has been described as the sustainable energy equivalent of Freakonomics.‘In a climate where people don’t understand the numbers’.. David tells us….  ‘newspapers, campaigners, companies and politicians can get away with murder.’ David was a leading scientist and mathematician in the UK, adviser to the UK government, and Cambridge professor so his words have some weight. Although not the easiest read, I’d definitely recommend ‘Sustainable Energy without the hot air’ as a must read for anyone interested in this topic…. and frankly, if you’re not interested in this topic, you should be!

And why is energy policy important? David makes three arguments:
1 – ‘it seems possible that cheap oil and cheap gas will run out in our lifetime.’
2 – we are interested in security of energy supply – dependence on fossil fuels makes us ‘vulnerable to the whims of untrustworthy foreigners.’
3 – ‘it’s very probable that using fossil fuels changes the climate.’ To fix climate change, we need to sort out a new way of getting energy. The climate problem is mostly an energy problem.’

Aim and approach

What does ‘Sustainable Energy without the hot air’ set out to achieve?

David’s aim in writing this book is to reduce ‘twaddle emissions’ – see what he did there with the word ’emissions’ 🙂 – twaddle emissions being emotional responses to the sustainable energy debate that aren’t backed by solid numbers. He contrasts two contemporary books that argue respectively that we are heading for an imminent energy crisis, and that we will be fine – ‘we are not heading for a major energy crisis’ the second book tells us. There is clearly a need in this debate for some cold hard facts and figures, and David is well-placed to provide these and an insightful analysis of these cold hard facts and figures.

The key questions the book attempts to answer is ‘can we feasibly live sustainably at our current levels of consumption, and if not, what can we do?’

What approach does it take?

David MacKay’s approach is to the first question is based on an analysis of the consumption and production possibilities in the UK. He provides estimates, for the UK, and at a high enough level to help ‘inform interesting conversations’, of the energy requirements on the consumption side, and the possible contributions that the various types of sustainable energy could make towards satisfying this consumption. Consumption is based on today’s levels of consumption (the book was published in 2009, but the figures are rounded to a level that they are almost certainly still relevant).

On the demand side he assumes a realistic level of increased efficiency – primarily in the transport and house heating sectors – and on the supply side he shows the real world implications of some of the numbers that would be required if we were to satisfy demand using sustainable energy.

Can we conceivably live sustainably?

To answer this question, David adds up all conceivable sustainable energy sources and then estimates the consumption of a “typical moderately-affluent person” in the UK. The calculations on the supply side don’t take economics into account, treat each source as an independent contribution (ie where only one of two choices could actually be used, both are included in the calculations), and don’t take into account any mismatch between the form and consistency of the supply compared to the demand requirements.

Some key forms of consumption are:
• transport
– cars, planes, freight
• heating and cooling

• lighting

• information systems and other gadgets

• food

• manufacturing

On the sustainable-production side, the main categories are:
• wind
• solar 
– photovoltaics, thermal, biomass
• hydroelectric
• wave
• tide
• geothermal
• nuclear? (with a question-mark, be- cause it’s not clear whether nuclear power counts as “sustainable”)

And the conclusions?

On a raw calculation basis, the energy requirements are slightly for the UK are slightly higher than the potential to produce power from renewables. 195kWh per person per day vs 180 kWh per person per day. And this without
taking into account the forms of the power, economic and social costs, and incompatibilities between different forms of renewable energy (ie double-counting).

…’technically, Britain has ‘huge’ renewables. But realistically, i don’t think Britain can live on its renewables – at least not the way we currently live. I am partly driven to this conclusion by the chorus of opposition that greets any major renewable energy proposal.’




The two conclusions from part one are:
1 – to make a difference, renewable facilities have to be country-sized. David rails a number of times against the advice that ‘every little helps’ – in reality ‘A more realistic mantra would be ‘if everyone does a little, we’ll achieve only a little.’ The scale of the problem is much bigger than switching off mobile phone chargers when not in use.
2 – we can’t get a plan that adds up using renewables only unless Brits are prepared to say ‘yes’ to things they would, and have been, saying ‘no’ to.

Ok, so what do we do?

Part two asks ‘assuming that we can’t get production from renewables to add up to our current consumption, what are the other options?’

‘We’ve established that the Uk’s present lifestyle can’t be sustained on the UK’s own renewables (except with the industrialisation of country-sized areas of land and sea). So, what are our options, if we wish to get off fossil fuels and live sustainably?

Reduce energy consumption.

David looks first at ways we could reduce our energy consumption needs by applying technology and using energy more efficiently. Roughly one third of our energy consumption goes into transport, so can technology deliver a reduction in consumption? His conclusion – we could halve the power consumption of transport (and defossillise it) by switching to electric vehicles. We could shrink the power consumption of heating even more by insulating all buildings better and using electric heat pumps instead of fossil fuels. But still, matching even this reduced consumption from Britain’s own renewables looks very challenging.

Use someone else’s renewables…

‘We’ve found that it’s hard to get off fossil fuels by living on our own renewables. Nuclear has it’s problems too. …how about living on someone else’s renewables?
Most of the resources for living sustainably are related to land area: if you want to use solar panels, you need land to put them on; if you want to grow crops, you need land again. Jared Diamond, in his book Collapse, observes that, while many factors contribute to the collapse of civilisations, a common feature of all collapses is that the human population density becomes too great.
Places like Britain and Europe are in a pickle because they have high population densities, and all of the available renewables are diffuse – they have small power density.

Unfortunately (my comment, not the author’s), the countries that fit the bill in terms of large area and low population density are not among the countries we’d want to rely on for our energy. Libya, Kazakhstan, Saudi Arabia, Algeria, Sudan. To supply Europe’s energy needs we would need solar panels in the desert covering a size 16 times that of Wales.

The Plan(s)

David goes on to outline in some detail five different plans that would make the supply and demand assumptions add up – each skewed to address one or more aspects of the problem at the expense of others. None of the plans look particularly attractive, and all require very major changes from our situation today.

‘If you don’t like these plans’ David tell us,  ‘I’m nor surprised. I agree that there is something unpalatable about every one of them. Feel free to make another plan that is more to your liking. But make sure it adds up!
‘Solving climate change is a complex topic, but in a single crude brush-stroke, here is the solution: the price of carbon dioxide must be such that people stop burning coal without capture. Most of the solution is captured in this one brush-stroke because, in the long term, coal is the biggest fossil fuel. Trying to reduce emissions from oil and gas is of secondary importance because supplies of both oil and gas are expected to decline over the next 50 years.’

‘Because Britain currently gets 90% of its energy from fossil fuels, it’s no surprise that getting off fossil fuels requires big, big changes – a total change in the transport fleet, a complete change of most building heating systems, and a 10 or 20 fold increase in green power.
Given the general tendency of the public to say ‘no’ to wind farms, ‘no’ to nuclear power, ‘no’ to tidal barrages – ‘no’ to anything other than fossil fuelled power systems – I am worried that we won’t actually get off fossil fuels when we need to.’

What now?

The situation looked pretty bleak in 2009. It looks much bleaker now for obvious reasons…

Review of Sustainable Energy without the hot air

I’d give David MacKay’s book 9/10. It was a very thorough and fact-based analysis of a very important problem, and I learned a lot about the various types of sustainable energy and their problems, and the various ways we could reduce consumption on a scale that would make a difference. The raison d’etre of the book was to talk facts and figures rather than opinions, but I got lost in the many calculations and units of measure – I know that most of the complicated stuff was quarantined in an appendix, but i still found myself glossing over a lot of the text in the body of the book. As with a lot of modern science, in my humble opinion, non scientists have to take some of the information we’re being told on faith – take a look at Stephen Hawking’s A Brief History of Time, for example. I believe in science, so I believe David’s analysis. But if there was a way of making it a little more accessible that would be good!

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