End-use technologies
According to the IPCC (2001, vol.3 Chapter 3), sufficient technical options exist to hold annual global
greenhouse gas emissions through 2010 to levels close to or even below those of 2000 -- and even lower
levels are possible by 2020. For energy-related CO2 emissions alone, the technological potential exists for
reductions of between 1,350 MtC/y and 1,900 MtC/y in 2010 and of 2,950 to 4,000 MtC/y in 2020. There
are, however, conflicting views as to the costs of taking such actions.
More than half of the potential comes from the aggregate effect of “hundreds of technologies and
practices” for end-use energy efficiency in buildings, transport and manufacturing. Most of this potential
may be tapped by 2020 with direct benefits – notably in the building and industry sectors (see IPCC 2001,
Vol.3, Chapter 3).
7.1.1 The building sector
CO2 emissions from fuels and electricity used in both residential and commercial buildings represent 98
per cent of all building-related GHG emissions. However, while developed countries have by far the
largest CO2 emissions from the building sector, energy use and related CO2 emissions from buildings in
developing countries, particularly in the Asia-Pacific region, have grown about five times faster than the
global average since 1980.
By 2010, it is projected that 500 MtC CO2 emissions from buildings could be avoided in developed
countries (including EITs) at negative costs, while in developing countries more than 200 MtC CO2
emissions could be saved at costs ranging from –US$200 to +US$50. Actions include improving building
thermal integrity, reducing the carbon intensity of fuels used in buildings, and increasing the energy
efficiency of appliances and equipment.
The technical and economic potential for CO2 emission reductions in the building sector extends to more
than 1 GtC by 2020 and not less than 2 GtC by 2050. However, the availability of technologies to achieve
such savings cost-effectively depends on significant R&D efforts, according to the IPCC.
The built environment can revolutionise the efficiency with which it uses energy for services such as
heating, lighting and cooling; can shift to renewable or non-carbon sources of energy and power; and can
transform itself gradually over time via modernisation and new construction. The future buildings sector
could be well integrated into a larger, integrated power and resource grid, with localised energy and
environmental management systems and controls. Future buildings could be almost alive with
communicating sensors, controls and microprocessors that manage energy requirements from central and
distributed power systems and that allocate energy to building equipment in response to user needs.
Buildings could use intelligent envelopes and components
(e.g., integrated photovoltaic cells, photoluminescent wall and floor boards, phase and adaptive materials for cladding, windows and roofs), local
power systems and energy storage systems, and ultra-efficient appliances; bio- and photonic sensors and
actuators; and biotechnology and other applications for water, air and waste purification.
The life cycle of raw materials for construction is another significant factor. There is a broad range of
possible innovations with regard to improving the competitiveness, attractiveness and technical
COM/ENV/EPOC/IEA/SLT(2003)4
34
performances of raw materials that are local, recyclable, non-fossil and energy-efficient in their
transformation and disposal processes.
Developments needed to support the emergence of such a future buildings sector include advances in
materials, “smart” building components, sensors and controls, and information systems. None of these
“futuristic” options for buildings, however, negate the importance of basic features such as passive solar
design, optimised insulation, and efficient district heating and cooling systems – technologies that are “on
the shelves” today.
