Renewable energy cannot sustain a consumer society

194 Pages·2007·0.5 MB·English

by  Ted Trainer

Renewable Energy Cannot Sustain A Consumer Society
Renewable Energy Cannot
Sustain A Consumer Society
By
Ted Trainer
University of New South Wales,
Kensington, NSW, Australia
A C.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN-13: 978-1-4020-5548-5 (HB)
ISBN-13: 978-1-4020-5549-2 (e-book)
Published by Springer,
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CONTENTS
Acknowledgement vii
1. The Context 1
2. Wind Energy 11
3. Solar Thermal Electricity 43
4. Photovoltaic Solar Electricity 59
5. Liquid and Gaseous Fuels Derived from Biomass 73
6. The “Hydrogen Economy” 93
7. Storing Electricity 101
8. Conclusions on the Potential and the Limits 107
9. Why Nuclear Energy is Not the Answer 119
10. The Wider Context: Our Sustainability and Justice Predicament 125
11. The Simpler Way 135
Notes 159
References 183
Terms 193
Units 195
Index 197
v
ACKNOWLEDGEMENT
Among the people who assisted with this project special thanks must go to Andrew
Ferguson of the UK Optimum Population Trust.
For summaries and documentary material on themes dealt with in this book,
intended for use by critical global educators, see The Simpler Way website
http://socialwork.arts.unsw.edu.au/tsw/
vii
CHAPTER 1
THE CONTEXT
In the last three decades considerable concern has emerged regarding limits to the
future availability of energy in the quantities required by industrial-affluent soci-
eties. More recently Campbell (1997) and others have argued that the energy source
on which industrial societies are most dependent, petroleum, is more scarce than had
previously been thought, and that supply will probably peak between 2005 and 2015
(Fleay, 1995, Ivanhoe, 1995, Gever, et al., 1991, Hall, Cleveland and Kaufman,
1986, Laherrere, 1995, Duncan, 1997, Bentley, 2002, Youngquist, 1997). Some of
these people argue that the world discovery rate is currently about 25% of the world
use rate, and that non-conventional sources such as tar sands and shale oil will not
make a significant difference to the situation. The USGS (2000) has recently arrived
at a much higher estimate for ultimately recoverable petroleum, but this would only
delay the peak by some 10 years.
If the discussion is expanded to take into account the energy likely to be required
by the Third World, the situation becomes much more problematic. If the present
world population were to consume energy at the rich-world per capita rate, world
supply would have to be five times its present volume. World population is likely to
reach 9.4 billion by 2070. If all these people were to consume fossil fuels at present,
rich-world per capita consumption rates, all probably recoverable conventional, oil,
gas, shale oil, uranium (through burner reactors), and coal (2000 billion tonnes
assumed as potentially recoverable), would be totally exhausted in about 20 years
(Trainer, 1985, Ch.4).
What is not well understood is the magnitude of the overshoot, the extent to which
our present consumer society has exceeded sustainable levels of resource use and
environmental impact. This is made clear by a glance at the greenhouse problem. The
Inter-governmental Panel on Climate Change (IPCC 2001, 2005, see also Enting,
et al., 1994) has given a range of emission rates and the associated levels that the
carbon dioxide concentration in the atmosphere would rise to.
• Perhaps the most quoted graph shows that if the concentration is to be stabilised
at 550 ppm, twice the pre-industrial level, emissions must be cut to 2.5 Gt/y by
2040 and to 0.2 Gt/y by about 2200. The present level from fossil fuel burning
(i.e., not including land clearing) is over 6 GT/y.
1
2 Chapter 1
• To keep the concentration below 450 ppm, emissions must be cut to about
1(cid:2)Gt/y by 2100, and to about 0.3 Gt/y by 2200. This target is much too high
because the atmospheric concentration is now at about 380 ppm and many disturb-
ing climatic effects are becoming apparent.
• The limit now often referred to as the maximum before catastrophic effects are
risked, such as the cessation of the Gulf Stream, is 400 ppm, associated with a 2
degree rise in temperature.
• If we were to stabilise the concentration at about the present level we would have
to cut emissions to about 0.5Gt/y by around 2040, and for some decades after 2070
we would have to extract more carbon from the atmosphere than we added.
It would seem clear therefore that our target should be at most 2 Gt/y, but a more
sensible target would be closer to 0.5 Gt/y. Yet what is the input that the Australian
Bureau of Agricultural and Resource Economics estimates we are heading for by
2050? An alarming 15 Gt/y.
If world population reaches 9(cid:2)billion, a global carbon use budget of 1 Gt would
provide us all with about 150 kg of fossil fuel per year, which is around 2–3% of our
present rich-world per capita use of fossil fuels (in GHGe terms). Alternatively only
about 170 million people, 2.5% of the world’s present population, could live on the
present rich-world per capita fossil fuel use of over 6 tonnes of fossil fuel per year.
These figures define the enormous magnitude of the sustainability problem we
confront. Consumer-capitalist society has overshot viable levels of production and
consumption by a huge amount. In effect we have to give up fossil fuels altogether.
That is, we have to live almost entirely on renewables. This book argues that these
very high levels of production and consumption and therefore of energy use that we
have in today’s consumer-capitalist society cannot be sustained by renewable
sources of energy.
However the foregoing numbers only define the magnitude of the present prob-
lem. This is nothing like the magnitude of the problem set when our commitment to
growth is also taken into account. As will be detailed in Chapter 10, if 9.4 billion
people are to have the “living standards” we in rich countries will have by 2070
given 3% economic growth, total world economic output every year would then be
60 timesas great as it is now.
The question of whether we can run our society on renewable energy is therefore
not about whether it can meet present demand, and this book concludes that it can-
not do that, it is about whether it can meet the vastly increased demand that will be
set by the pursuit of limitless increase in production and consumption.
There is an overwhelmingly powerful, never questioned, assumption that all these
problems can and will be solved by moving to renewable energy sources. That is, it
is generally believed that sources such as the sun and the wind can replace fossil
fuels, providing the quantities of energy that consumer society will need, in the
forms and at the times that they are needed. Surprisingly, almost no literature has
explored whether this is possible. Wildly optimistic and highly challengeable claims
are often encountered. “Hydrogen is abundant. All we need is water.”1 “It is esti-
mated that renewable energy has the potential of meeting the energy demand of the
The Context 3
human race well into the future.” (Lewis, 2003). “... existing renewable energy
resources are capable of substituting for coal-fired power stations...” (Diesendorf,
2005, p. 1). “Renewable energy and energy efficiency can deliver the power we
need, without the problems.” (ACF, 2005). “...energy crops can provide ample
biofuel feedstock.” (Lovins, et al., 2005, p. 107). “All observers of energy seem to
agree that various energy alternatives are virtually inexhaustible.” (Gordon, 1981,
p. 109). “An entirely renewable and thus sustainable electricity supply is possible
using existing technologies.” (Czisch, 2004). “Solar energy can replace fossil and
nuclear fuels over the next 50 years thus creating a truly sustainable energy supply
system.” (Blakers, 2003).
Unfortunately in the task of assessing the validity of this dominant assumption we
have not been helped by the people who know most about the field, the renewable
energy experts. They have a strong interest in boosting the potential of their pet tech-
nology and in not drawing attention to its weaknesses, difficulties and limits.
Exaggerated, misleading, questionable and demonstrably false claims are often
encountered in the promotional literature. Minor technical advances which might or
might not become significant in the long run are announced as miraculous solutions.
Doubts regarding the potential of renewable technologies are rarely if ever heard
from within these fields.
This enthusiasm is understandable in view of the need to attract public support
and research funding, but it means that contributions by those most familiar with
these fields to the critical assessment of the potential and limits of renewables are
quite rare. In developing the following review, considerable difficulty has been
encountered from people hostile to having attention drawn to the weaknesses in
their technologies and proposals (including threats of legal action if data they have
provided in personal communications is used). Sources eager to provide information
tend to dry up when they realise that limits are being explored. In addition some of
the crucial information will not be made public by the private firms developing the
new systems. For example it is almost impossible to get information on actual wind-
mill output in relation to mean wind speeds at generating sites. Where commercial
interest might be threatened by critical inquiry, prickly reactions, including harass-
ment, can be encountered.
Unfortunately these difficulties have meant that at times it has not been possible
to get access to information that would settle an issue and that must exist some-
where, and that at times one has to attempt an indirect estimation using whatever
scraps of information one has been able to find. Ideally this study would have been
carried out by someone more expert in renewable energy technology than I am, but
it is understandable that the task has been left for an outsider to take up.
This is not an exhaustive examination of all the various renewable energy sources
but it attempts to be a sufficient analysis, i.e., to deal well enough with the crucial
issues which seem to enable a persuasive case. A number of technologies which
might make a significant difference some day have not been examined closely
because there are not persuasive reasons to think they can rival the main four
options, wind, solar thermal, photovoltaics and biomass.
4 Chapter 1
1.1. THE TWO CORE PROBLEMS
There are two vital problems for renewable energy, the provision of electricity and
of liquid fuels. Renewable energy can meet various needs very well, or perfectly in
many regions, such as heating and cooling space via simple “solar passive” designs
whereby the structure captures and stores solar energy. However renewables face
formidable problems with respect to the two forms of energy which consumer
society demands in enormous quantities, viz. electricity and liquid fuels. The funda-
mental issue in both cases has to do with the quantity of energy that can be delivered
reliably, not dollar cost or “energy return”.
The situation is clearest with respect to liquid fuel (i.e., oil plus gas). Chapter 5
seems to show quite conclusively that there is no possibility of getting the quantity
we take for granted, no matter what plausible assumptions are made regarding tech-
nical advances. There are only two possible sources of renewable liquid fuels,
biomass and hydrogen. Even wild optimism about potential land and energy yields
cannot provide the world’s future 9.4 billion people with more than perhaps 10% of
the per capita liquid fuel consumption we now average in rich countries.
The situation concerning electricity is less clear cut. Some regions such as north-
east Europe and the US will be able to derive a lot of electricity from the wind in
winter (although the situation in summer is much more problematic). Yet even if the
quantity of wind and solar electricity was not a problem, very difficult problems
remain having to do with making these highly variable forms of energy available at
the times when they are needed.
It is quite misleading to focus on the contribution a renewable source can make
when it is merely augmenting supply largely derived from coal or nuclear sources.
In that situation the significant problems set by the variability of renewables can be
avoided. When the sun is not shining or the wind is not blowing, a little more coal
can be burned. However the problem this book is concerned with is the development
of systems in which almost all energy used comes from renewables, and that means
we would have to provide for large fluctuations in energy production, and thus for
the storage of large quantities of energy. At this point in time there is no satisfactory
solution in sight for this problem, on the scale that would be required.
Electricity is more or less impossible to store in very large quantities, so it has to
be transformed into something that can be stored, such as hydrogen or pumped
water, then transformed back to electricity when it is needed. However these
processes involve significant difficulties and costs, as Chapters 6 and 7 will discuss.
The best option, using electricity to pump water into high dams and then using its
power to generate electricity when there is insufficient wind, involves the problem
of limited hydro-capacity. Less than 10% of world electricity is generated by hydro-
electric generating power, so this source cannot carry anywhere near the full load
when there is little wind or sun.
In other words the biggest difficulties for solar and wind energy are set by their
variability, especially the occurrence of nigh time and winter for solar, and the
fact that winds can be down for days at a time. Many sites with quite satisfactory
The Context 5
summer PV or solar thermal performance are almost useless right through winter,
especially in Europe. Winds tend to be low in summer and autumn. Even more prob-
lematic for wind are the large variations from day to day as gales and calms occur.
At present it seems that the variability of wind means that it probably cannot pro-
vide more than 25% of demand in the best wind regions, and perhaps no more than
10 to 15% in most good wind regions. Variability also seems to mean that if we build
a lot of windmills we might also have to build almost as much coal or nuclear
generating capacity, to use when the winds are down.
The belief that the world will soon run on a “hydrogen economy” is very com-
mon. Chapter 6 will explain why this is not likely. The first challenge to this faith-
based assumption is the question of a source for the huge quantities of hydrogen that
will be required. Chapters 2, 3 and 4 explain why we are not likely to get enough
energy from solar or wind sources to meet electricity demand, let alone have any left
over to convert into hydrogen. But even if we had a lot of hydrogen, there are coer-
cive arguments as to why we still could not have a hydrogen economy. These involve
the difficulties posed by the physical nature of the very small and light hydrogen
atom. Large volumes of hydrogen have to be pumped or stored before much energy
arrives at the destination, and this consumes a lot of energy. In fact according to one
estimate, pumping hydrogen from the Sahara to northern Europe would use up the
equivalent of 65% of the energy pumped. Then there would be other losses and
energy costs in moving the hydrogen into fuel tanks, and especially driving motors
and generating electricity. Finally fuel cells are likely to deliver at most 50% to 60%
of the energy that reaches them as hydrogen after all those pumping losses.
If the losses are combined, we find that to provide electricity or run vehicles from
wind power via hydrogen would require 3 or 4 times as much wind-generated energy
as there is in the petrol we are trying to replace. Similar losses would be involved in
storing wind-generated power in hydrogen and using it to regenerate electricity later.
The capital cost of such a generating system could be 12 to 15 times as much as that
of the coal-fired generating system, not including the cost of the hydrogen produc-
tion, pumping, storage and fuel cell systems.
This poses the question of what multiple of present electricity cost could be
tolerated. Our economy might survive if electricity cost five times as much as it does
now, but could it survive a 10-fold increase?
What about using solar energy in summer and autumn when the winds tend to be
low, and wind in the winter when there’s little sun? This would mean constructing
two very expensive systems in addition to the one we have now. We would have the
wind system, the solar system and the coal-fired system for use when the other two
are not working.
These are brief indications of the significant difficulties and costs that lie along
the renewable paths, and especially the hydrogen, path. Chapters 2 to 7 provide
detailed supporting evidence for the validity of these concerns. Chapter 8 briefly
summarises the reasons for concluding that the four main renewable sources cannot
sustain the resource-extravagant society we have in rich countries today. Chapter 9
briefly explains the reasons why nuclear energy cannot solve the problem.