Solar Energy Perspectives - IEA

Chapter 12: Conclusions and recommendations
Chapter 12
Conclusions and recommendations
The sun offers mankind virtually unlimited energy potential. Only wind power comes close,
only biomass is equally versatile. Solar energy can be tapped in many ways, which should
be combined to best fulfil the energy needs of the global population and economy. Because
it is available all over the planet, it can provide faster access to modern energy services for
the disadvantaged communities in rural areas with low population densities. It can also help
them meet their energy needs for cooking, displacing ways of using biomass that are often
inefficient, unhealthy and not sustainable.
For the bulk of the world population, solar energy can provide inexhaustible and clean
electricity in large amounts, only surpassed by wind power in temperate and cold countries.
Electricity will be the main carrier of solar energy, displacing fossil fuel use with efficient
motors and heat pumps, drawing heavily on solar and geothermal ambient energy.
An integrated approach to the deployment of solar energy needs first to assess and characterise
all energy needs, then to identify the smartest possible combination of sources to meet those
needs. Wherever possible, passive city and building designs maximising day lighting, solar
heat capture (or shielding from excessive solar irradiance) should be preferred. Wherever
possible, direct heat should be preferred to more elaborate forms of energy in responding to
heat needs. Using ambient energy wherever possible is even better; the only costs are in
raising temperature levels.
Similarly, depending on the climatic conditions, effective combinations of solar, wind,
geothermal, hydro power and biomass resources will generate ample quantities of clean and
renewable electricity. Whether other carbon-free technologies are available or not, an almost
complete decarbonisation of electricity generation is possible. Only balancing plants with
low capacity factors should have residual CO 2 emissions, which could be further minimised
by using solar hydrogen blended with natural gas, unless biogas can also be produced in
sufficient amounts.
The most difficult challenges in a future of very low greenhouse gas emissions will be
displacing fossil fuels that are in direct uses in industry and transport. But the combination of
electricity, mainly from solar and wind, and biomass can reduce fossil fuel usage to quite low
levels, while in industry carbon capture and storage (if proven in large-scale applications)
should further reduce CO 2 emissions.
Prediction is very difficult, especially about the future, as the great Danish physicist Niels Bohr
stated. The exact contribution of solar energy by 2060 and after cannot be known or decided
yet. Many other climate-friendly options may appear, and the hopes some put in carbon
capture and storage or nuclear may materialise. Efficiency improvements may be faster or
slower than expected. Substitution of fossil fuels with electricity may also be faster or slower
than anticipated, while hydrogen may play more of a role than foreseen in this publication.
Ocean energy and enhanced geothermal energy may become important contributors.
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© OECD/IEA, 2011