broschuere ee zahlen en bf

aVOIDeD eMIssIONs
28 Renewable Energy Sources in Figures
Emissions avoided in the heat sector in 2010 by using renewables
Apart from the use of solar energy and ambient heat, renewable energy for space heating
and hot water in households and for industrial process heat comes largely from CO 2 -neutral
combustion of biomass. Here the amount of CO 2 released is no more than the plant previously
took up for its growth.
Thus heat supply from renewables makes an important contribution to avoiding greenhouse
gas emissions. This climate protection effect is due partly to avoiding the release of the carbon
bound in fossil fuels such as oil, natural gas, coal and lignite, and partly to avoiding environmental
pollution (e.g. methane emissions) produced during the extraction, processing
and transport of fossil fuels.
However, where biomass is burned in older heating installations such as stoves, greater quantities
of air pollutants are released than in the case of fossil fuels (the emission balance becomes
negative). This applies particularly to the volatile organic compounds which contribute
to photochemical smog, and to carbon monoxide and particulate emissions of all sizes. Such
environmental pollution can be reduced by using modern heating systems and stoves and by
a responsible approach on the part of the user.
With regard to the greenhouse gas avoidance factors of the individual renewable energy
sources, the picture is similar to the production of electricity from renewables. A particularly
high climate protection effect results from the use of solid biomass (wood) and biogenic
waste. In the case of heat generation from biogas, the emissions arising from cultivation of
the energy crops are once again relevant.
With regard to the avoidance factors for solar energy and geothermal energy, it should be
noted that these are not based on fuel input, but directly on useful energy.
Greenhouse gas avoidance factors for renewables-based heat generation, 2010
Heat
Avoidance factor
[g CO eq./kWh]
2
Biogenic solid fuels (households) 302
Biogenic solid fuels (industry) 304
Biogenic solid fuels (Hp/CHp) 286
Biogenic liquid fuels 277
Biogas 157
sewage gas 267
landfill gas 267
Biogenic fraction of waste 292
solar thermal energy 225
Deep geothermal energy 64
Near-surface geothermal energy 1) 84
the avoidance factor is the quotient obtained
by dividing avoided emissions by renewablesbased
heat generation. It represents the average
avoidance of greenhouse gases and air
pollutants (for further information, see annex).
1) Including miscellaneous ambient heat
sources: BMu on the basis of aGee-stat and
other source, see following table