Environmental Engineering Reference
In-Depth Information
1
Energy Demand of Buildings
Buildings today account for 40% of the world's primary energy consumption and
are responsible for about one-third of global CO
2
emissions (24% according to IEA,
2008; 33% according to Price
et al
., 2006). The energy-saving potential is large, with
20% savings expected until 2020 in the European Union alone. The cost efficiency
of building-related energy savings is high, as shown in a recent study for the Inter-
governmental Panel on Climate Change ( Urge-Vorsatz and Novikova, 2008). In the
industrialized countries, between 12 and 25% of building-related CO
2
emissions can
be reduced at net negative costs, mainly through heat-related measures. In the devel-
oping countries, electricity savings through more efficient appliances and lighting are
more important with 13 to 52% of the measures being economically feasible until
2020. As published in the Green Paper on energy efficiency by the European Com-
mission, end energy-consumption in 2005 reached 12
10
9
MWh per year, 40% of
which can be attributed to buildings (see Figure 1.1). In the USA, 36% of the total
energy consumption occur in buildings. Especially in urban areas, building energy
consumption is typically twice as high than transport energy, for example by a factor
of 2.2 in London (Steemers, 2003).
Under the Kyoto Protocol, the European Union has committed itself to reducing
the emission of greenhouse gases by 8% in 2012 compared with the 1990 level and
buildings have to play a major role in achieving this goal. If building energy efficiency
is improved by 22%, 45 million tonnes of CO
2
can be saved, nearly 14% of the agreed
total savings of 330 million tonnes.
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