Solar Energy Perspectives - IEA

Solar Energy Perspectives: Testing the limits
In less sunny countries, both costs and variability could be limiting factors, calling for
a relatively smaller contribution of solar electricity – mostly or exclusively PV. Electricity
imports from sunnier regions could significantly raise this contribution, as the difference in
solar resource is likely to cover electricity transportation costs over significant distances. The
Desertec Industrial Initiative aims to provide Europe with 15% of its electricity, mostly from
solar plants in North Africa. However, greater share of imports would likely raise or increase
concerns about energy security.
Importantly, this chapter does not offer a modelling exercise showing the least-cost
combination. Such modelling would draw supply cost curves, with changes in marginal costs
as each type of technology increases its share in the mix. What makes the simplified picture
offered here still relevant, though necessarily less precise and conclusive, is the fact that when
it comes to solar and wind, the technical potentials are much greater than the projected uses.
This means that over time the deployment-led cost reductions will not tail off due to exhaustion
of the low-cost resource. Another consequence is that the potentials for solar and wind are not
limited by the resource but rather by the demand – or the costs of addressing their variability
over time, which increase with their shares in the electricity and energy mixes.
Variability
Large seasonal electricity storage, when not provided at low cost by reservoirs for
hydropower, would be tremendously expensive. Thus, the electricity mix would largely
depend on the seasonal variations in the availability of the various resources, and demand
variations. Storage would thus be required mostly on a daily basis to offset rapid variation
of the generation of variable renewables when renewables constitute a large proportion of
the mix.
In hot, sunny but humid regions with lower DNI, and cold, not-too-sunny but usually windy
regions, the match between resource availability and peak demand is also usually good, on
both seasonal and daily timescales. For example, whether suitable for CSP or not, Asian
countries subject to the monsoon have lower domestic and agricultural (water-pumping)
electricity demands during the monsoon months – as well as increased available hydropower.
Existing or to-be-developed hydropower plants would likely provide a large part of the
balancing needs, as suggested by the example of Brazil and the considerable hydropower
potential of central Africa.
Sunny countries will host most of the forthcoming growth in population and activities. Larger
countries such as the United States and China have very sunny areas, some with very good
DNI, and others with good diffuse irradiance. In the most northern European countries,
northern Canada and eastern China, which still represent a significant share of current
economy and energy consumption, the variability of the solar resource requires specific
solutions, and the optimal energy mix is likely to include a great variety of resources.
Wind power, more abundant in winter, is likely to play an important role as demand peaks
in winter in cold countries, although this may change over time. Demand for air-conditioning
may increase and demand for heat decrease, resulting from better building insulation,
improved standards of living, and climate change. In Europe today, a combination of 40% PV
and 60% wind power – whatever their share in the overall electricity mix – would closely
match the seasonal variations of electricity demand (Figure 11.3).
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© OECD/IEA, 2011