Solar Energy Perspectives - IEA

Chapter 4: Buildings
the overall potential, followed by commercial buildings in North America by a large margin
and in Japan, while in several European countries and Australia agriculture buildings come
second, except for Germany and Italy where industrial buildings come second. Overall, these
estimates suggest that solar electricity generation on buildings can reach substantially higher
levels than seen in most projected scenarios to 2050. Note that the results presented in
Table 3.1, as well as the comparison of electricity needs and PV production shown on
Figure 4.10 do not take into account the possible substitution of large amounts of heating
fuels by electricity in heat pumps.
Cooking
Cooking usually represents less than 10% of energy consumption in buildings in IEA
member countries. By contrast, it represents a major component of consumption in
developing countries, and contributes to indoor air pollution and its associated lung
and eye diseases, as well as major difficulties of fuel-wood collection, and
desertification when harvesting exceeds regeneration.
In industrialised and emerging countries the solutions rest on efficiency improvements,
notably allowed by electric induction techniques, which could allow more solar and
renewable energy. Direct solar cooking techniques are not considered for day-to-day
use.
In developing countries things can be very different. Techniques for cooking at
different temperature levels range from low-cost hotboxes to concentrating parabola
(see Chapter 7).
Attempts to make these devices popular have so far had mixed results, as regular use
requires major changes in families’ habits and lifestyle. Community kitchens have
been quicker to discover the merits and advantages of solar cooking, especially fuel
savings, as in India (Photo 4.6) with the Scheffler dishes described in Chapter 7.
The need for an integrated approach
Buildings are large consumers of energy, but there are many options to reduce this
consumption and at the same time transform buildings into significant energy producers.
Energy-efficiency improvements and solar options must be associated to minimise the
consumption and maximise the production of renewable energy, in order for zero-net energy
buildings and even positive energy buildings to become a reality. The appropriate combination
depends on climatic conditions, heating and cooling needs, use of the buildings, solar
resources, available space, and the proportions of new building and renovation.
There is no one-size-fits-all solution, but there are some guiding principles. Energy efficiency
rests primarily on insulation and optimal thermal masses. Passive solar heating and cooling,
and day-lighting, must be considered first. Solar hot water generation can produce high
proportions of domestic hot water needs and substitute for electric water heating in clothes
and dish washing machines. Solar space heating and cooling, and appropriate storage, need
to be further developed. Combinations of reversible (preferably ground-source) heat pumps,
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© OECD/IEA, 2011