How Energy Is Produced - The Renaissance of Renewable Energy - page 123

processes, and peak load power during daytime. Furthermore, in arid countries it can meet
growing demand for water desalination (DESERTEC 2009 ; IEA 2010b ) .
Parabolic troughs are the most mature of the CSP technologies and therefore dominate
the current market (REN21 2012 ). Currently, the cost of installing a 50-megawatt CSP
plant is around € 4,800 per kilowatt. The costs of electricity from large solar troughs with
six hours of thermal storage range from 20 to 30 U.S. cents (2005) per kilowatt-hour. In
very sunny locations, with solar radiance of 2,500 kilowatt-hour per square metre per year
(e.g., in North Africa, Middle East, the southern United States, and central Australia), costs
may be 20-30 per cent less (Arvizu et al. 2011a ; IEA 2009a ; JRC 2011 ; REN21 2012 ).
Although global capacity increased almost fivefold, from 354 to 1,707 megawatts
between 2005 and 2011, CSP has not seen the same explosive proliferation as solar PV
or wind power have. When we consider that 95 per cent of that capacity is in just two
countries (Spain and the United States), it is clear that CSP as a global energy solution
is still in its infancy. Currently, the deployment of CSP technology is limited by regional
availability of good-quality irradiance of 2,000 kilowatt-hours per square metre or more
(Arzivu et al. 2011a ). New projects are under way in Italy, the Middle East, North Africa,
India, and China (IEA 2009a ; JRC 2011 ; REN21 2012 ; Shahan 2012 ).
The Potential of CSP
Carlo Rubbia, the Italian nuclear physicist and Nobel laureate, has long been a strong
advocate of CSP. In 2005, after completing his term as director of ENEA, 16 he was
appointed principal scientific adviser to CIEMAT, a Spanish public research organization
on energy, environment, and technology. Under his guidance, Spain has now become the
world leader in CSP (Ombello 2010 ) . According to Rubbia ( 2012 ) , the technical potential
of CSP, especially in the vast desert zones, is immense but barely tapped. Incredible as
it may sound, the amount of solar energy that strikes the world's deserts in six hours
is roughly equal to humankind's entire annual energy consumption. Roughly 1 per cent
of the 36 million square kilometres of the Earth's deserts, an area roughly the size of
Germany or Japan, would therefore be sufficient to satisfy the entire annual primary energy
consumption of humankind (DESERTEC 2009 ) . 17
CSP potential is estimated at roughly 8,000 exajoules per year, 15 times current global
production (Krewitt et al. 2009 ). Therefore, the main limitation to CSP expansion is
not the availability of suitable ground space, but rather technical and economic factors.
Technical limitations include the fact that, as an intermittent energy source, CSP cannot
provide base-load power as fossil fuels do. Also, because CSP plants are best suited to
hot deserts, long distances between the sites of production and consumption need to be