I have a confession to make.
“Sustainable Energy – without the hot air” had mostly gathered dust on
my bookshelf for almost two years before I finally took the time to
finish reading it. So why did I take it up again and finalise it this
time (and, more importantly, bother to write this review and try and
convince you to read it yourself)?
Well,
in the last few months, several reports have been published, outlining
how it would be possible to run an economy without fossil fuels in the
foreseeable future – I suppose that this sudden outburst is not
completely unrelated to the preparation of the European Commission’s
roadmap for a low-carbon future.
While
the headlines of these reports caught my attention, in most cases, I
rather quickly abandoned reading them. The main motivation for
doing so was not that I fundamentally disagreed with the authors’
conclusions, but rather that the published material was not sufficiently
concrete to help me make up my mind on the validity of these
conclusions. Indeed, any report looking 40 years or more into the future
is inevitably speculative. There is nothing wrong with that: taking
into account the stock nature of greenhouse gasses, we have no choice
but to think about the very-long-term consequences of today’s choices.
However, with such a time horizon, it is clear that any conclusion you
draw can depend critically on some assumptions that may appear to be
minor but that have dramatic cumulative impacts in 40 years from now.
Therefore, complete transparency with respect to the assumptions used
(and how they translate into conclusions) is essential for any
publication on this subject. It was precisely because this transparency
was lacking in most publications on the subject that I felt that a
further reading would not really enlighten my own thoughts.
It
was then that I recalled that complete transparency was the key selling
point of “Sustainable Energy” (one should not take “selling” too
literally, as the book can be downloaded freely). To his own admission,
the main motivation of the book’s author, David MacKay, a professor of
Physics in Cambridge, is his concern about cutting the emissions of
“twaddle about sustainable energy”. He starts from the observation that
many of the things that allegedly make a difference in terms of energy
consumption simply do not add up. However, he rightly points out that
the debate about sustainable energy is one about numbers, and that in a
climate where people don’t understand numbers, anyone can get away with
murder (or energy plans that do not add up).
The
book is essentially a case study of whether it is possible to draw up
an energy plan for a country (in this case, the United Kingdom, but the
methodology can be readily applied to any country) that would cover its
entire energy needs without the use of fossil fuels.
MacKay proceeds as follows.
In
the first half of the book, he compares the country’s energy
consumption with “sustainable” energy production. His approach is
bottom-up pushed to the extremes. On the consumption side, he takes any
possible activity that uses energy (transport, heating and cooling,
light, “gadgets”, food, etc) and estimates the corresponding energy use
of a “typical” household. On the production side, he considers all
possible sources of sustainable energy (on-shore wind, solar,
hydropower, offshore wind, wave, tide and geothermal). The only
constraint MacKay considers are physical
constraints. His main motivation for deliberately ignoring economic or
environmental constraints is that doing so helps focusing on the
question whether conceivable sustainable energy production would be enough to cover total consumption.
After
having verified the results of his bottom-up estimates with actual
energy consumption (according to official statistics), Mac Kay goes on
to the second half of the book, where he verifies whether an appropriate
mix of demand (better transport, more efficient heating etc) and supply
(importing renewables from abroad, nuclear, even coal with carbon
capture and storage) measures would result in a renewable energy mix
that actually adds up.
In
case you cannot wait to read the book, the answer to the feasibility
question is: yes, it is physically possible to fulfil a country’s energy
needs with renewable energy but (even if one ignores economics) it will
be far from obvious and it will require some drastic changes in current
consumption and production patterns. Actually, the author even hints
that some climate engineering may be needed in case the sums for
mitigation do not add up (see my discussion of Superfreakonomics for
more on this). Whether you like this conclusion or not, I would strongly
recommend to find out the details of the argument for yourself, and to
verify whether you can agree with them.
What
is really wonderful about this book, is that you can indeed verify
every single step in the argumentation. Moreover, you can put all the
assumptions in a spreadsheet, and verify how the results changes
according to geography (you may well live in a country with a very short
shoreline but lots of spare place and sun) or time (some of the
technical assumptions may change quickly and unexpectedly when time
unfolds – for instance, The Economist of 12 March hints that the
potential for increased energy efficiency in aviation is much higher
than Mac Kay’s estimates).
To
put it simply, this is probably the most transparent book I have ever
read, and it sets a very high standard for any future work in this
field.
Through
its emphasis on verifiable facts and figures, rather than on
perceptions, the book is also very good at demystifying a lot of
misconceptions (no, you will not save the planet by unplugging your
mobile-phone charger when it’s not in use; yes, there are limits to
energy efficiency that are not imposed by economics, but simply by the
laws of physics etc), which can only lead to a better informed debate
(in case, of course, that’s what you’re interested in).
Of
course, the level of detail and the emphasis on hard facts may also put
a lot of people off (despite the tongue-in-cheek humour, it is hardly
compelling bed-time reading, which may explain why it lingered on my own
“to read” list for so long). I suppose that’s the eternal dilemma
of books that are meant to be intellectually rigorous but that aim at a
general audience at the same time: there’s an unavoidable trade-off
between rigour and accessibility. This is typically the kind of book
that boffins will enthusiastically recommend as being very “accessible”,
just to find out that no one except their own kind shares this
enthusiasm.
This being said, are there any other issues with the book?
Actually,
it covers so much ground, that I do not feel qualified to comment on
most of the details (when I wrote that you can verify every detail in
the book, what I really meant is that it is possible to set up a team of
experts to verify everything ).
Let me therefore limit my discussion to the few subjects where I think I know a thing or two more than Professor MacKay.
First,
transport. MacKay makes a compelling case for the (physical) limits to
energy efficiency in private transport. However, I am afraid he is way
too optimistic concerning the potential of public transport. I do not
dispute that public transport is, on average, much more energy efficient
than private transport. However, current averages are a very poor
predictors of actual energy efficiency if a massive shift from private
to public transport were to take place. Indeed, public transport can
only be more energy efficient than private transport if it used to move
huge (more or less predictable) quantities of people from one
(predictable) origin to a (predictable) destination. In other words: it
is mainly efficient in peak time in urban areas. The problem is that a
significant amount of people who are currently using their car for
moving around do not fall into this category (they live spread around in
large suburban areas, their work places are dispersed in other large
suburban areas, etc). If these people would switch to public transport,
energy efficiency of public transport is likely to decrease, not
increase. Of course, my reasoning depends also on specific assumptions
with respect to spatial structure: one may retort that the promotion of
public transport should go hand in hand with measures against urban
sprawl. Now, that’s a point I fully agree with, but the reality is that
spatial structure is like housing: poor choices that were made in the
past are likely to stay with us for a very, very long time. So, to
summarize, in some countries where public transport has been underfunded
or poorly organised, there is probably some potential to improve the
energy efficiency of the transport system by promoting a modal shift.
Also, this may be an interesting policy option for the hundreds of
cities that will be built in India and China in the decades to come, and
where spatial structure remains to be defined. But do not think you can
stretch the potential of public transport much further in many European
urban areas.
Second,
economics. Of course, as an economist, I would have liked to see a more
thorough discussion of the economics of sustainable energy (the
solutions with the highest technical potential are not necessarily the
ones with the highest cost-effectiveness). However, I understand
Mackay’s point that you should evaluate the physical feasibility of an
economy entirely based on renewable before you even consider
economics. Actually, I would have preferred if MacKay would have stuck
to this approach throughout the book, because most of what he has to say
on economics does not come close to the analysis of other issues. For
instance, MacKay finds it odd that people have faith in market, “given
how regularly markets give us things like booms and busts, credit
crunches, and collapses of banks”. Very well. Using a similar line of
argument, I find it odd that people have faith in governments, given
that that they gave us things like decades of economic stagnation and
mass famine (Soviet Union and China under Mao), and mass massacres
(Birkenau, the Gulag and the Cambodian killing fields were organised by
government bureaucracies, were they not?). If you think this argument is
a caricature, I agree – it is. But not much more than the diatribe
against markets that you can find in Chapter 29 of the book.
My
point here is: finding out what is technically achievable is an
essential first step in a move to an economy that is based upon
renewable energy. However, it is only a first step. Once you go further
than that, you have to define priorities and you must design
institutions that will induce the desired changes in a
cost-effective manner. While the design of these institutions should
indeed involve legislation, regulation and taxes (as argued by MacKay),
there is nothing dogmatic about affirming that you also need to harness
the power of market forces to induce these most cost-effective
reductions.
By
the way, I also have a substantial comment or two to make on the
economics. Electrical vehicles may have a lot of technical potential,
but, for the foreseeable future, most economists reckon that their cost
per tonne of CO2 saved is up to an order of magnitude larger than the
cost per tonne of CO2 saved in other sectors of the economy (such as
housing). I also doubt that the costs of all
sources of renewable energy can be expected to drop in the future:
whilst technological progress may induce lower prices, higher demand
will also put upward pressure on prices. I do not think we can predict
which effect will dominate. However, discussing these issues in depth
should be the subject of a separate post on this site.
Third,
MacKay barely touches upon the energy and non-energy resource cost of
creating the infrastructure that will provide all this renewable
energy. This is not a trivial matter. Actually, some have argued
recently that the main constraint on moving to a low carbon economy is
that it will not be possible within the coming decades to mine all the
minerals that are needed in the creation of this infrastructure. This is
maybe an issue that should be considered in a new edition of the
book.
Of
course, within the larger picture, these are minor comments. On the
whole, this book is an impressive intellectual achievement. As it is
freely available on-line, you do not have the excuse of the cost for not
downloading it right away and making up your mind yourself (and, more
importantly, for not forwarding it to all policy makers you know).
And,
oh please, don’t forget to repeat its core one-liner to everyone you
know: if everyone does a little, we’ll achieve only a little.
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