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3 Technological and Economic Potential of Mitigation Options
3.1 Key Developments in Knowledge about Technological Options
to Mitigate GHG Emissions in the Period up to 2010-2020 since the Second Assessment
Report
Technologies and practices to reduce GHG emissions are continuously being developed.
Many of these technologies focus on improving the efficiency of fossil fuel energy
or electricity use and the development of low carbon energy sources, since the
majority of GHG emissions (in terms of CO2 equivalents) are related
to the use of energy. Energy intensity (energy consumed divided by gross domestic
product (GDP)) and carbon intensity (CO2 emitted from burning fossil
fuels divided by the amount of energy produced) have been declining for more than
100 years in developed countries without explicit government policies for decarbonization,
and have the potential to decline further. Much of this change is the result of
a shift away from high carbon fuels such as coal towards oil and natural gas,
through energy conversion efficiency improvements and the introduction of hydro
and nuclear power. Other non-fossil fuel energy sources are also being developed
and rapidly implemented and have a significant potential for reducing GHG emissions.
Biological sequestration of CO2 and CO2 removal and storage
can also play a role in reducing GHG emissions in the future (see also Section
4 below). Other technologies and measures focus on the non-energy sectors
for reducing emissions of the remaining major GHGs: CH4, nitrous oxide
(N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur
hexafluoride (SF6).
Since the SAR several technologies have advanced more rapidly than was foreseen
in the earlier analysis. Examples include the market introduction of efficient
hybrid engine cars, rapid advancement of wind turbine design, demonstration
of underground carbon dioxide storage, and the near elimination of N2O
emissions from adipic acid production. Greater energy efficiency opportunities
for buildings, industry, transportation, and energy supply are available, often
at a lower cost than was expected. By the year 2010 most of the opportunities
to reduce emissions will still come from energy efficiency gains in the end-use
sectors, by switching to natural gas in the electric power sector, and by reducing
the release of process GHGs from industry, e.g., N2O, perfluoromethane
(CF4), and HFCs. By the year 2020, when a proportion of the existing
power plants will have been replaced in developed countries and countries with
economies in transition (EITs), and when many new plants will become operational
in developing countries, the use of renewable sources of energy can begin contributing
to the reduction of CO2 emissions. In the longer term, nuclear energy
technologies – with inherent passive characteristics meeting stringent
safety, proliferation, and waste storage goals – along with physical carbon
removal and storage from fossil fuels and biomass, followed by sequestration,
could potentially become available options.
Running counter to the technological and economic potential for GHG emissions
reduction are rapid economic development and accelerating change in some socio-economic
and behavioural trends that are increasing total energy use, especially in developed
countries and high-income groups in developing countries. Dwelling units and
vehicles in many countries are growing in size, and the intensity of electrical
appliance use is increasing. Use of electrical office equipment in commercial
buildings is increasing. In developed countries, and especially the USA, sales
of larger, heavier, and less efficient vehicles are also increasing. Continued
reduction or stabilization in retail energy prices throughout large portions
of the world reduces incentives for the efficient use of energy or the purchase
of energy efficient technologies in all sectors. With a few important exceptions,
countries have made little effort to revitalize policies or programmes to increase
energy efficiency or promote renewable energy technologies. Also since the early
1990s, there has been a reduction in both public and private resources devoted
to R&D (research and development) to develop and implement new technologies
that will reduce GHG emissions.
In addition, and usually related to technological innovation options, there
are important possibilities in the area of social innovation. In all regions,
many options are available for lifestyle choices that may improve quality of
life, while at the same time decreasing resource consumption and associated
GHG emissions. Such choices are very much dependent on local and regional cultures
and priorities. They are very closely related to technological changes, some
of which can be associated with profound lifestyle changes, while others do
not require such changes. While these options were hardly noted in the SAR,
this report begins to address them.
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