Can Africa's desert sun power Europe?
Up to 20% of power demand in Europe can be obtained by connecting African deserts to European cities, according to the DESERTEC Foundation.
The idea is to build a large number of concentrated solar power (CSP)
plants in Middle Eastern and Northern African (MENA) countries, and to
transmit electricity to Europe by means of efficient high-voltage
direct-current cables.
CSP in deserts, as explained in greater detail
below, has the potential to generate renewable electricity, predictably,
for up to 16 hours per day, thus overcoming two major problems with
photovoltaic and wind power: intermittency and few operation hours.
A prominent technology roadmap of the
International Energy Agency published in 2010 had optimistic prospects
for CSP, and projected a significant amount of electricity transmission
from MENA countries to Europe – up to 15% of total electricity
consumption in 2050 (see IEA 2010).
The DESERTEC project has lost traction since Siemens withdrew from
the partnership in October 2012, but the idea of building a
trans-Mediterranean power grid is still attractive for many proponents
of a quick transition towards a zero-emission European power system.
The main questions we address in this column are the following:
- Is it economically, technologically and politically feasible to cover a large fraction of power demand in Europe from the MENA deserts?
We answer these questions by relying on numerical scenarios generated
using the integrated assessment model WITCH to study when, how much and
where it is optimal to invest in CSP, and what the potential size of an
EU–MENA power market is (Massetti and Ricci 2013). We find that it is
premature for Europe to invest now in large CSP projects. There is scope
for pilot projects, but large economic benefits from
trans-Mediterranean CSP trade emerge only from 2050 onward. However, the
threats to European energy security from extensive trade in electricity
with MENA countries should not be underestimated.
The need for a carbon-free power generation system
Europe is setting increasingly strict greenhouse gas
emission-reduction targets, with the intent to lead the world in the
fight against climate change. If Europe truly aims at achieving the
heralded +2°C temperature limit, more stringent targets will follow
because aggregate emissions must basically drop to zero.
With uncertain prospects in Europe for both nuclear power and
fossil-fuel power plants with carbon capture and storage, renewables
will likely play a major role in the future technology mixture. The
problem with renewables such as wind and photovoltaic is that they are
intermittent – winds are erratic and the sun does not shine at night. A
power system that relies on wind and photovoltaic for the bulk of its
generation capacity must be upgraded with new transmission and
distribution grids, with storage capacity and backup capacity. This is
expensive and thus penalizes renewable technologies, compared with coal
or natural-gas thermoelectric power plants (EPRI 2011 and IEA 2014).
Concentrated solar power
The ideal technology should provide steady, adjustable, predictable
power from totally renewable sources. CSP generation is very close to
this optimum. The idea is extremely simple and as old as Archimedes’
mirrors during the Siege of Syracuse – reflecting surfaces are used to
concentrate direct sunlight in a narrow area to heat a fluid. The fluid
is collected and used to transform water into steam, which is then used
to rotate a turbine in a thermoelectric plant. Direct sunlight
substitutes coal and gas. The temperature reached by the fluids during
the day is so high that it is possible to store heat for most of the
night and generate an almost continuous stream of power. A natural gas
turbine may complement the system to guarantee 24-hour power generation.
The major drawback of CSP is that it needs virtually cloud-free sky
(unlike photovoltaic, which works well even under cloudy skies). The
best sites for CSP are deserts because the lack of humidity largely
reduces average cloud coverage. Deserts also offer large inexpensive
areas of land to host large expanses of mirrors. The problem is that
deserts are usually not close to where people live and work. The idea is
then to use new generation transmission cables that have minimal power
losses to connect deserts to cities.
With a few exceptions in Spain and in southern Italy, Europe lacks
the best climatic and geographic conditions for CSP. A large-scale
development of CSP is not possible in Europe. However, many of the
states on the southern Mediterranean shore have an abundance of deserts
with ideal climatic conditions – hence the plan to build a network of
cables up to central and northern Europe.
Economic, technological and political feasibility
CSP is a proven technology that can work on a large scale. The
leading country is Spain, with 2300 MW of installed capacity, followed
by the US, where four plants became operational in the past 10 months,
reaching 1435 MW of total installed capacity. More plants are to come in
2014 and the following years in the US, China, India, South Africa, and
other countries in the Middle East and Northern Africa (Figure 2).
Is CSP economically attractive? At present, CSP power generation is
four or five times more expensive than fossil power generation (see IPCC
2011). Of the investment in CSP, 98% so far has needed public support
(Stadelmann et al. 2014). But how would investment incentives change if
carbon emissions start being penalized and learning-by-doing contributes
to reductions the investment and operation costs of CSP? Will a
climate-friendly investment environment incentivize large investments in
CSP, and will it become attractive for Europe to import CSP from the
deserts of Africa and of the Middle East?>>>
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