Targets IMage Energy Regional (TIMER) Model, Technical ...

RIVM report 461502024 page 25 of 188
valued added for the services sector (Va serv ), private consumption for the residential sector (PC)
and Gross Domestic Product (GDP) 11 per capita for the transport and ‘other’ sector. Within the
IMAGE 2.2 framework, the exogenous scenarios used for changes in these activity indicators
are based on the WorldScan-model (CPB, 1999b). This ensures a certain consistency, not only
between the different sectors but also between the different regions.
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In the industrialised regions there is clear evidence of the role of structural change in trends in energyand
material-intensities. For instance, between 1973 and 1994 aggregated structural changes in the mix
of sectoral activities drove up energy use between 0.1 – 0.7% per year for selected OECD countries
(Unander, 1999). These aggregated changes can be the result of various underlying trends. A major
factor behind the decrease in energy use per unit of GDP is, as indicated above, ‘a gradual transition of
the output mix in the direction of information- and value-intensive, but material-extensive, products
and the availability of higher-quality and lighter substitutes in the form of advanced materials’
(Grübler, 1990).
However, there are also other, more equivocal factors at work. Demographic factors such as decreasing
household size and ageing may lead to higher energy-intensity 12 . The growing importance of energyintensive
transport modes and the ongoing electrification of offices, on the other hand, tend to increase
energy-intensity, as do life-style related changes such as the increasing size/weight of new cars and the
purchase of electric waterbeds and garden lights. Yet, one may also think of life-style changes which
result in lower energy-intensity. For instance, if people in the developed regions feel a widening gap
between economic activity and well-being, a reduced emphasis on activity-growth and increasing
support for ‘green’ technologies and investments may emerge. Such a ‘greening’ or ‘dematerialization’
of the economy is usually thought to bring down the energy use per unit of GDP. Finally, changes in
the regional import and export flows and the dynamics of technology transfer may also cause
significant changes in the energy intensity. There is evidence that part of the energy-intensity reduction
in the OECD has been realised by a shift from energy-intensive production to import of energyintensive
materials (Schipper, 1997).
Due to lack of data and different and less well understood dynamics, the picture for the less
industrialised countries is at least as complex. It is often assumed that with industrialisation the energyintensity
in the less industrialised countries will strongly rise, following the historical development
trajectories of currently industrialised countries. This, however, may not or only partly happen, because
late-comers have important catching-up possibilities and countries are quite heterogeneous with regard
to process and product saturation levels. This argument clearly makes sense for much of
manufacturing. In transport, canals and railways may never reach the densities they reached in Europe
but the preferred automobile-road system may actually lead to a more energy- and material-intensive
development pattern than Europe’s historical trajectory. More generally speaking, a key question is
whether the industrialising countries will follow current European and North-American life-styles.
To simulate the second type of structural changes, the intensity of energy use in each sector
((TQ) is modelled as function of a selected ‘driver of change’, also indicated as Driving
Force per caput DFpc (see 7DEOH ). Available data suggest that the resource intensity in
physical units per monetary unit can be represented by a bell-shaped function of the caput
activity level DFpc (Vuuren, 2000). Energy intensity starts at low levels, in a stage in which
fuels and electricity are minor inputs. If activity levels rise, producers and consumers will start
to purchase capital goods which require commercial fuels and electricity to operate - ovens,
machinery, cars and trucks, stoves, heating and air-conditioning installations, washing
11 Although we use regions, we still use Gross Domestic Product, GDP.
12 (Ironmonger, 1995) projects an increase of 2.4% of residential energy use per caput due to the expected further decline in
Australian households.