IEEE Technology and Society Magazine - March 2015 - 43

the rebound effect partly takes back the impact of efficiency gains. Greening [13] distinguishes four different
categories of this implication:
■ Direct rebound effect: Higher energy efficiency in
producing a service or product leads to lower costs
and a lower price. A lower product and service price
induces higher demand, leading to increasing production and resource use.
■ Indirect rebound effect: Money saved by lower
prices of goods and services achieved by energy
efficiency causes increasing consumption of other
goods and services. Such implications are called
secondary effects.
■ Economy-wide effects: Higher energy efficiency
could lead to lower market prices for energy, due
to less energy demand. It is generally accepted that
lower energy prices induce faster economic growth
and therefore higher resource usage.
■ Transformational effects: Advances in technology,
like higher energy efficiency, possibly influence the
activities and preferences of consumers. This could
change global energy demand, but the consequences are very hard to predict and explain.
The potential impact of the rebound effect reflects
the uncertainty about the extent of the positive environmental effect of the use of ICT for improving energy efficiency. Studies suggest that in most cases the
total impact of the rebound effect can be considered
to be relatively minor from a macro-economic perspective. The determined percentage of reduced energy savings by the rebound effect differ from 2-3% [14]
to around 26% [15]. The rebound from increased energy efficiency can be considered to be less than 30%,
but there is no expert consensus on this, because
of the "lack of a sound theoretical framework that
can explain sufficiently the complex interactions that
accompany energy efficiency improvements in the
macro-level" and "inconclusive historical, empirical
and econometric evidence" [16]. In conclusion regarding the impact of the rebound effect on energy efficiency: it is unlikely that the rebound will take back
the entire carbon savings enabled by more energy
efficient technologies.
In the long run it is quite certain that increases in
global energy demand will be larger than the benefits
of improving energy efficiency. This makes "energy
efficiency policies... short-term policy instruments"
[16] and postulates the need for carbon-free energy
sources to achieve long-term reductions in carbon
dioxide emissions.
The term emission savings is used for denoting
reductions in the amounts of emitted greenhouse
gases. To allow a consistent comparison, emissions and
emissions savings are often defined in carbon dioxide
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equivalents, i.e., emissions are calculated as they would
only contain carbon dioxide. The notation of carbon
dioxide equivalent is CO2 e.
The enabling effect of ICT is based on the capability of optimization and dematerialization. Which leads
directly or as a side-effect of energy efficiency to emissions savings (see Fig. 3). The substitution of physical
high-carbon products by almost carbon-free virtual

In the long run, increases in global
energy demand will be larger
than the benefits of improved
energy efficiency.

products saves emissions by directly avoiding the highcarbon products. But reductions in emissions can also
be directly linked to energy efficiency, as emissions savings often arise as a byproduct of energy efficiency.
In this context the question is whether energy efficiency improvements achieved by the benefits of ICT
will actually lead to emissions savings. This question is
represented by the rebound effect. Therefore the actual
carbon reductions will depend on the rates of energy
efficiency improvements in relation to the growth rates
of the global energy demand [11]. From an economic
point of view this will be a matter of the development of
energy prices and consumer preferences, as these two
factors are mainly influencing demand and, in consequence, energy consumption.

The Carbon Footprint with Respect
to Environmental Concerns
The carbon footprint of a person, a product, a service,
a company, or a whole economic sector determines
the amount of total greenhouse gas emissions this unit
causes in a defined period of time. For example, every
economic sector has a carbon footprint that functions
as a measure of sustainability and can therefore be
used to benchmark the progress of reaching environmental goals (see Fig. 2). In other words, the carbon
footprint represents the amount of carbon [or carbon
dioxide equivalent] emissions associated with a given
entity or activity. The carbon footprint is a ratio that
testifies to how much impact products and actions
have on the environment.
The concept of the carbon footprint has become to
a kind of "common currency for many environmental

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