Abstract This viewpoint discusses the intra- and international distribution of energy consumption and their implications for intergenerational equity. For global development to be sustainable, the inequality of energy consumption must have an upper limit. A graphic depiction of energy consumption distributions (intra- and international) shows that today’s inequalities are large andit is arguedthat we may have already reachedor perhaps even surpassed the sustainability limit of energy consumption inequality.

1. Energy Policy 33 (2005) 1905–1911
Viewpoint
Distribution of energy consumption and the 2000 W/capita target
Daniel Spreng*
Centre for Energy Policy and Economics, Swiss Federal Institutes of Technology, ETH Zentrum WEC C, Zurich CH-8092, Switzerland
Available online 24 June 2004
Abstract
This viewpoint discusses the intra- and international distribution of energy consumption and their implications for
intergenerational equity. For global development to be sustainable, the inequality of energy consumption must have an upper
limit. A graphic depiction of energy consumption distributions (intra- and international) shows that today’s inequalities are large
and it is argued that we may have already reached or perhaps even surpassed the sustainability limit of energy consumption
inequality.
r 2004 Elsevier Ltd. All rights reserved.
Keywords: Energy consumption; Inequality; Equity; Sustainable development
1. Introduction
In discussions on the sustainability of energy systems
much weight is placed on the supply side of the energy
system (e.g. Schenler et al. (2002) and other contribu-
tions in the same special issue of The International
Journal of Sustainable Development). However, the
supply side view often reduces sustainability to ecolo-
gical concerns and a sustainable energy system is
equated with an environmentally friendly energy supply
system. In emphasising energy demand we attempt to be
broader than that.
All definitions of sustainability have two elements in
common: (1) the simultaneous consideration of ecolo-
gical, economic and social aspects and (2) the con-
sideration of the next generations. Open to debate is
what we mean by ‘‘consideration’’. Should ecological,
economic and social aspects be treated with equal
weight, if so, how can this be achieved? Analogously,
what weight should the consideration of the next
generation assume and how should well-being and
opportunities of our generation be compared with
well-being and opportunities of future generations?
In what follows, I will discuss how the undisputed
aspects of sustainability could be applied to energy
consumption. I argue that ecology dictates an upper
limit to energy consumption, economic development a
lower limit and social considerations a limit to the
spread of energy consumption per capita within society.
I, therefore, propose the concept of a window for the
sustainable development of the per capita energy
consumption.
In the analysis of whether a particular development is
sustainable or not we are bound to accept today’s energy
consumption as a starting point and ask whether the
next generation’s situation might be tolerable or not. As
we can make direct decisions only for our own
generation, it does not make much sense to look into
the future beyond the next generation. Therefore, I will
discuss the energy consumption of the next generation,
let us say of the year 2050 and call a development
sustainable that aims at a situation in 2050 that is not
obviously unsustainable.
2. Upper limit for the sustainable per capita energy
consumption
Energy consumption per se does not have a relevant
upper limit. Except for the situation in particular cities,
waste heat is many orders of magnitudes below levels
that affects the environment in a significant way.
However, today’s energy consumption impacts the
environment in many serious, unsustainable ways.
Energy supply and consumption leads to a large fraction
ARTICLE IN PRESS
*Tel.: +411-632-4189; fax: +411-632-1050.
E-mail address: spreng@cepe.mavt.ethz.ch (D. Spreng).
0301-4215/$ - see front matter r 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.enpol.2004.03.023

2. of environmental insults (see e.g. UNDP, 2000). How-
ever, besides the emission of CO2, most of the other
pollutants can and are being reduced to tolerable levels.
Indoor and outdoor air pollutions are being reduced by
emission control equipment, fuel cleaning techniques
and by fuel switching. The cost of these measures are not
disrupting the economics of the system, the degree to
which they are implemented is a matter of choice by
society, today and in years to come.
CO2 emissions are different. There is no plausible
path of development in which they are eliminated by
2050. In scenarios most aggressively limiting CO2
emissions the emission levels in 2050 are about what
they are today (IPCC, 2000) and are decreasing only
after that time below today’s level. The reason for this is
that all three ways of drastically reducing CO2
emissions, the procurement of carbon-free primary
energy resources, CO2 sequestering and the development
and implementation of much more efficient technologies
and lifestyles take time. Let us look at these three
approaches briefly.
The development and installation of energy supply
systems based on carbon-free primary energy resources
requires large investments. In some cases, like the solar
electric systems, more development is needed, to reduce
cost before they can be installed on a massive scale.
Wind energy farms are suitable if their contribution is
not too large a share of the energy input to the electric
grid, otherwise expensive back-up systems are necessary.
In the case of nuclear systems, new generations have to
be developed, which may possibly win the public’s and
investors’ approval.
The technology and practice of sequestering CO2 is
potentially expensive, has possibly some safety problems
and is only at the start of its development. The
prerequisite for this practice is an international binding
commitment to limit CO2 emissions. Nobody will go to
the trouble and expense to sequester CO2, if not
everybody agrees to do it. Years will pass before an
agreement of this kind is in place that includes most
nations.
Similarly with today’s low-energy prices that do not
reflect their true cost to society, and with the low level of
attention to energy efficiency, new, highly efficient
technologies and lifestyles will also take time to be
introduced. Of the three options to reduce CO2
emissions, energy conservation through increased effi-
ciency is the most cost effective and could be introduced
without delay, even though it will take a long time until,
for instance, an entire building stock is renewed. The
massive consumption of carbon-free primary energy
resources and the practice of sequestering CO2 will, in
the very long run, be solutions to the CO2 problem.
However, without an energy efficiency crash pro-
gramme, they will be too slow to meet the 2050 CO2-
emission requirements. Furthermore, these solutions
will not be affordable to society, if the energy use is
not curbed, i.e. if their implementation is not preceded
by massive improvements in energy efficiency.
Based on this discussion, the upper limit of global
average per capita energy consumption can readily be
calculated from the climate models. For scenarios,
which are on a path to a stabilisation of the climate in
the long run, CO2 emissions in 2050 are around or below
8 Gt/year. With a world population of approximately 8
billion at that point, this corresponds to 1 t/year capita
and, further, with today’s average carbon content in
primary energy this translates to 2000 W/capita. If the
carbon content in primary energy is by that time
reduced to half of today’s average value, an extremely
ambitious goal only conceivable in conjunction with a
massive energy efficiency programme, 1 t/year capita
would correspond to 4000 W/capita.1
3. Lower limit for the sustainable per capita energy
consumption
No development is sustainable, if it does not include
progress towards the alleviation of poverty and the
associated, necessary economic development. Usually,
poverty is measured in monetary terms. But most
lifestyles above the poverty level are associated with
a certain minimum level of energy consumption. This
level has been discussed and determined by engineering
type estimates of the direct energy required to satisfy
basic needs. Such calculations are reported in early
studies by Bravo (1979) cited in Krugman and
Goldemberg (1983), Goldemberg et al. (1985, 1987),
Goldemberg (1990) and Revelle (1976). Goldemberg
et al. estimated that the requirement of direct primary
energy per time unit to satisfy basic needs is about
500 W per person. Including indirect energy consump-
tion, i.e. the energy requirement for producing the
goods, such as food, clothing and shelter, forming part
of basic needs, one has to double this number, thus
arriving at 1000 W/capita.
This kind of a calculation rests on a number of
assumptions regarding the type of energy consuming
equipment (stove, light bulbs, etc.), their sizes, efficien-
cies and intensity of consumption. In addition, the
approach requires as a first normative step the definition
of a set of basic needs. This is a problematic endeavour.
Obviously basic needs vary not only with climate,
region, period in time, age and sex, but also with
personal outlook and expectations.
In addition, there is a question of the proper level in
the energy chain, from primary energy to energy
ARTICLE IN PRESS
1
Following Goldemberg, we use the unit of power (energy per unit
time) in W (=J/s), when referring to energy needs per person.
Obviously, 2000 W=2 kWh/h=2 Á 8760 kWh/year.
D. Spreng / Energy Policy 33 (2005) 1905–19111906

3. services, at which the minimum level of energy
consumption should be determined.
As this lower limit is at least partially normative, any
number can be disputed. I refer to a detailed discussion
of this issue in respect to the case of India (Pachauri and
Spreng, 2004) and pick half of the 1000 W/capita
number, i.e. 500 W/capita (for the direct plus indirect
energy consumption). In India 500 W/capita is about
today’s average and it affords in the average the energy
service of two cooked meals a day, some light from a
kerosene lamp and the indirect energy required to
produce food, necessary to not go hungry, simple
clothing and shelter. With improved efficiencies of
stoves, other equipment and production in industry
and agriculture, 500 W/capita will provide for more
energy services, but with continued globalisation the
perception of poverty will also change and the
normative determination is likely to increase rapidly.
4. Limit for the spread of sustainable per capita energy
consumption
There is wide acceptance of the idea, that there is
some measure of inequality that leads to social conflict.
There is also general agreement that people should have
equal opportunities. Slavery, the medieval class system
and Indian castes have been and are being abolished. All
men (and women) are born equal, as the US declaration
of independence says. However, what measure of
inequality is beneficial, or at least not harmful, is open
to debate.
An interesting debate on this issue is given in the
winter 2002 issue of DAEDALUS. Galbraith (2002)
starts the discussion with a detailed analysis entitled ‘‘A
perfect crime: global inequality’’. The third article in the
issue by Epstein (2002) also agrees that today’s inequal-
ities, particularly those running along the US racial
divide, are ‘‘a sorry state of affairs’’, but his main
message is summarised in the last paragraph of his
article: ‘‘John F. Kennedy had it right when he said that a
rising tide lifts all the boats. And that tide will only rise
when we put aside our preoccupation with redress and
redistribution—and agree instead to unleash the produc-
tive capacities of all our citizens’’. Whereas in the last
century inequalities within nations have been the main,
or one of the main topics of politics, in the coming
century, politics most likely will be pre-occupied with
inequalities between nations.
Usually, inequality is discussed in terms of income or
some related monetary measure. I argue, that looking at
the per capita energy consumption—particularly if we
agree that this measure does have an upper limit as
discussed above enriches the discussion. The existence of
a lower limit is accepted both for monetary measures
and for the per capita energy consumption. However,
the upper, ecological limit to the average per capita
energy consumption does not exist for monetary
measures.
If per capita energy consumption is used as the
surrogate measure of well-being, its upper limit makes
the concept of the rising tide inapplicable.
The developments described in some of the stabilisa-
tion scenarios of IPCC’s Special Report on Energy
Scenarios do not only include the stabilisation of CO2
output but also minor economic improvements for
developing countries. The overlooked question, how-
ever, is whether the spread of energy consumption is not
also a serious issue in regard to sustainable develop-
ment. For a development to be sustainable, free of large
social conflicts, we must be on a path leading in 2050 to
a situation with a limited spread in energy consumption.
The continued large CO2 emission by rich countries robs
the poorer countries the possibility of rapid develop-
ment and the use of the common, cheap CO2-sink.
The following graph (Fig. 1) depicts the inequality in
today’s energy use (an older version of this graph was
constructed in a diploma thesis (Schmieder and Taor-
mina, 2001). It shows the energy consumption per capita
of 73 countries, wherever possible for the year 2000
(IEA, 2003). This alone is not new. New is that we have
included for every country the estimated energy
consumption per capita of the richest 10% and the
poorest 10% of the population (decile)2
(CIA, 2003; The
ARTICLE IN PRESS
2
To calculate the energy consumption of the top and bottom decile
we assume that the total energy-income elasticity for all countries is the
same, namely 0.8. It is a rounded average number taken from the
literature. It has been studied in detail for the Netherlands by Vringer
and Blok (1995), their value is 0.83. The corresponding number for
Australia is 0.73 (Lenzen, 1998). For urban households in India a value
of 0.67 has been reported (Pachauri, 2004) and for urban households in
Brazil a value of 1.01 (Cohen et al., 2004). These numbers refer to the
dependence of the total commercial energy (both direct and indirect)
on income at a given time within one country. In Fig. 2 we use 0.8 also
for the world as a whole, which is as good an assumption as any. The
calculation of Podobnik (2002) addresses only the inequalities between
country averages.
The spread of energy consumption between the top and the bottom
decile, DE ¼ Etop2Ebottom; is calculated as follows from knowing the
averages for the per capita income and for the per capita energy
consumption, Iaverage and Eaverage and the income of the top and the
bottom decile, Itop and Ibottom:
Etop ¼ Eaverage þ ðDItopEaverage=Iaverage0:8Þ; ð1Þ
Ebottom ¼ Eaverage À ðDIbottomEaverage=Iaverage0:8Þ; ð2Þ
where DItop ¼ Itop À Iaverage and DIbottom ¼ Iaverage À Ibottom:
For some cases the net import of embodied energy in goods and
services make a per capita comparison with other countries not very
meaningful. For Switzerland the per capita energy consumption has,
for that reason, been augmented by 25% to compensate for the large
net import of embodied energy. Luxembourg and Trinidad have been
eliminated from the list because the large exports of embodied energy
are unknown to the author.
D. Spreng / Energy Policy 33 (2005) 1905–1911 1907

4. ARTICLEINPRESS
Fig. 1. Energy use per time and capita in various countries and within countries (average consumption as well as consumption of highest and lowest decile of users).
D.Spreng/EnergyPolicy33(2005)1905–19111908

5. World Bank Group, 2003). Furthermore, a 2000 W/
capita line is drawn. 2000 W/capita is both not far from
today’s world average and can, as we have seen, be
considered an average compatible with sustainable
development in the long run.3
With these two additions,
the graph presents not only international inequalities
but also, at one glance, intra-national and inter-
generational inequalities.
The graph shows a troubling situation regarding
inequality in present energy consumption, within
countries, and across countries.
5. Equity: Rawls’ two considerations
From the vast spectrum of literature on inequality
and inequity I pick one philosopher who has thought
about intra- and international inequity: Rawls (1971)
suggests in A Theory of Justice that the correct judgment
about the distribution of goods (material and other) in
society is to look at the disadvantaged members. He
does not argue that everybody should ideally have the
same, or, that the image of the rising tide is wrong, but
that the proof of the pudding was the state of affairs of
the poorest. If, over the course of time the plight of the
poor improves in a nation, the distribution of wealth
becomes more just.
Can we apply the same criterion when comparing
poverty in different countries? Rawls (1997) discusses
this question in his last book, The Law of Peoples. This
book is less well known, but is of particular interest for
the assessment of international inequalities and inequi-
ties. Rawls comes to the conclusion, that there is no
similar equity criteria between peoples as within one
people: Each one of us does have some responsibility for
his neighbours and for fairness within his and her
society, such that we share a responsibility for the plight
of the poor in our society. However, other people have
different traditions and rules. We can and may not be
responsible for how other people distribute their wealth.
An important matter for which we do share respon-
sibility, Rawls writes, are, however, international
treaties, conventions and dealings. If they lead to
injustice and contribute to keeping people in less well-
of countries poor, we, in the richer countries are
responsible for the contribution of these international
treaties, conventions and dealings to global inequity.
Rawls values national sovereignty highly. Younger,
human rights-scholars and politicians4
would argue that
ARTICLE IN PRESS
Fig. 2. The energy consumption window. The upper, ecological boundary refers to the global average and is drawn between 2 and 4 kW/capita
depending carbon content of the total primary energy used in 2050. The lower boundary is chosen at 600 W/capita and refers to the poorest decile of
the global society in 2050. The distribution ‘‘World tomorrow without social boundaries’’ is calculated assuming the average to increase to 3 kW/
capita and the proportional distance between the average and the lowest and top decile to remain constant. Solidarity is the principle idea of the
2000 W/capita society. The social boundaries and the energy distribution in the 2000 W society are drawn in an exemplary way. More conventional
stabilisation scenarios possibly over-step social boundaries to a not sustainable degree.
3
The term 2000 W/capita society was chosen a few years ago, when
the world average energy use was in fact 2000 W/capita.
4
Resolution adopted by the General Assembly (A/RES/55/2),
United Nations Millennium Declaration, I. Values and Principles,
para. 2: ‘‘We recognize that, in addition to our separate responsibilities
to our individual societies, we have a collective responsibility to uphold
D. Spreng / Energy Policy 33 (2005) 1905–1911 1909

6. in our global society solidarity should go beyond
international treaties and conventions. However, even
taking fairness more seriously in respect of these treaties,
conventions and dealings, would go a long way towards
more global justice.
6. Utopia, novatlantis and the 2000 W/capita society
Assuming the spread of energy consumption will lead
to global, social unrest, some scientists in Switzerland
and elsewhere have began thinking about the feasibility
of drastically reducing per capita energy consumption in
post-industrial societies (see description of project
novatlantis, 2004).
Utopia is the title of a book by Sir Thomas More,
which was published in Latin in 1516. The work
describes the ideal state, in which everything is organised
rationally for the equal good of everyone, where all
scourges of society, such as poverty and distress are
eliminated. Solidarity, central to the idea of the 2000 W/
capita society, is utopian in its original meaning.
Sir Francis Bacon, English thinker and writer of the
early 17th century, propagated both scientific method
and the value of science to society. In ‘‘The New
Atlantis’’ (1627) he describes a happy—although not
egalitarian—nation that considered the ‘‘light’’ of
knowledge and the careful attention to the adherence
to law its most precious goods.5
Today like at the beginning of the renaissance, some
analysts see the dawn of an age of information. It is not
scientific method that lies at the root of today’s possible
renaissance, but technological capabilities. Information
technology makes it possible for information to be
omnipresent, in technical processes and for decisions
everywhere (Spreng, 1993). This, in principle, can lead to
massive improvements of energy efficiency and reduc-
tions of waste. Information technology provides the
possibility for a resource-efficient new Atlantis. How-
ever without a conscious effort by society, information
technology is more likely used to greatly increase
wasteful automated mass production.
7. Concluding remarks
The 2000 W/capita society can be seen as combination
of Utopia, in its original, egalitarian meaning, and New
Atlantis; as happy, science-based society. But it can also
be viewed much more pragmatically. There is no way
that OECD countries can keep increasing their CO2
emissions without contributing to a large and most
likely catastrophic climate change. Even keeping their
CO2 emissions constant, i.e. limiting their per capita
energy consumption to a very moderate increase,
commensurate with the increase of non-fossil fuel energy
use, would either leave the inequity in terms of CO2
emissions at today’s high, potentially explosive level or,
if, as we hope, developing countries develop sufficiently
to reduce poverty on a large scale, global CO2 emissions
would still lead to a considerable change of climate.
As the energy consumption in 2050 will have to be not
much more than 2000 W/capita on the global average in
order to be ecologically sustainable, technologies and
lifestyles compatible with that energy consumption will
be needed. An economy such as Switzerland and other
OECD countries that live on creating and exporting
technology, will be in a good position, if their exports
serve the needs of the time. It is only wise for technology
producing countries to aim at the future market of the
2000 W/capita society in terms of their technology
policy. This is a matter of good business strategy.
Energy policy, in turn, should be directed at reducing
per capita energy consumption. By how much we reduce
our own energy consumption is a question of solidarity
(cf. Fig. 2). Massive reductions in OECD countries
would perhaps even leave room in the global CO2-
emission budget to allow poverty eradication as
stipulated in the UN millennium goals without trigger-
ing catastrophic climate change.
Acknowledgements
Many thanks to Andr!e Kemmler for re-calculating
and re-drawing Fig. 1. The financial help of novatlantis
(www.novatlantis.ch) is gratefully acknowledged.
References
Bacon, F., 1627. The New Atlantis. The short full text is available on
http://www.constitution.org/bacon/new atlantis.htm.
CIA, 2003. The World Factbook. http://www.odci.gov/cia/publications/
factbook/fields/2047.html.
Cohen, C.A.M.J., Lenzen, M., 2004. Energy requirements of house-
holds in Brazil. Energy Policy, in press.
ARTICLE IN PRESS
(footnote continued)
the principles of human dignity, equality and equity at the global level.
As leaders we have a duty therefore to all the world’s people, especially
the most vulnerable and, in particular, the children of the world, to
whom the future belongs’’.
5
Novatlantis was constructed as a haven for information. I quote
from Bacon (1627): ‘‘When the King had forbidden to all his people
navigation into any part that was not under his crown, he made
nevertheless this ordinance; that every twelve years there should be set
forth out of this kingdom, two ships, appointed to several voyages; y.
whose errand was only to give us knowledge of the affairs and state of
those countries to which they were designed; and especially of the
sciences, arts, manufactures, and inventions of all the world; and
withal to bring unto us books, instruments, and patterns in every kind:
y rewarding y. [the owners], as they should think fit’’. On their
voyages the ships should sail under flags of foreign nations and make
use of the people that had previously stranded and then treated as
guests on the island.
D. Spreng / Energy Policy 33 (2005) 1905–19111910

7. Epstein, R.A., 2002. Against redress. Daedalus—Journal of the
American Academy of Arts and Sciences Winter 39–48.
Galbraith, J.K., 2002. A perfect crime: inequality in the age of
globalization. Daedalus—Journal of the American Academy of
Arts and Sciences Winter 11–25.
Goldemberg, J., 1990. One kilowatt per capita. Bulletin of the Atomic
Scientists 46(1).
Goldemberg, J., Johansson, T.B., et al., 1985. Basic needs and much
more with one kilowatt per capita. Ambio, 14 (4–5), 190–200.
Goldemberg, J., Johansson, T.B., et al., 1987. Energy for a Sustainable
World. Wiley-Eastern Limited, New Delhi.
IEA, 2003. Key Energy Indicators per Country. http://www.iea.org/
stats/files/selstats/keyindic/keyindic.htm.
IPCC, 2000. Emission scenarios. IPCC Special Report, Cambridge
University Press.
Krugman, H., Goldemberg, J., 1983. The energy cost of satisfying
basic human needs. Technological Forecasting and Social Change
24, 45–60.
Lenzen, M., 1998. Primary energy and greenhouse gases embodied in
Australian final consumption: an input–output analysis. Energy
Policy 26 (6), 495–506.
novatlantis, 2004. http://www.novatlantis.ch/.
Pachauri, S., 2004. An analysis of cross-sectional variations in total
household energy requirements in India using micro survey data.
Energy Policy 32 (15), 1723–1735.
Pachauri, S., Spreng, D., 2004. Energy use and energy access in
relation to poverty. Economic and Political Weekly, January 17.
Podobnik, B., 2002. Global Energy inequalities: exploring the long-
term implications. Journal of World-Systems Research 8 (2),
252–274.
Rawls, J., 1971. A Theory of Justice. Belknap Press of Harvard
University, Cambridge, MA.
Rawls, J., 1997. The Law of Peoples. Belknap Press of Harvard
University, Cambridge, MA.
Revelle, R., 1976. Energy use in rural India. Science 192 (4), 969.
Schenler, W.W., Gheorghe, A.V., et al., 2002. Strategic electric sector
assessment methodology und sustainability conditions. The Inter-
national Journal of Sustainable Development 5(1/2 Special Issue)
pp. 7–63.
Schmieder, B., Taormina, N., 2001. Energieverbrauchsfenster. Diplo-
marbeit ETH Z.urich, ORL-Institut and CEPE.
Spreng, D., 1993. Possibility for substitution between energy, time and
information. Energy Policy 21 (1), 13–23.
The World Bank Group, 2003. Data Query. http://devdata.worldbank.
org/data-query/.
UNDP, 2000. World Energy Assessment: Energy and the Challenge of
Sustainability. J. Goldemberg, New York.
Vringer, K., Blok, K., 1995. The direct and indirect energy
requirements of households in the Netherlands. Energy Policy 23
(10), 893–910.
ARTICLE IN PRESS
D. Spreng / Energy Policy 33 (2005) 1905–1911 1911