Concentrating solar power (CSP)-which is quite different from the better-known photovoltaics-is the simple but effective technique of concentrating sunlight with mirrors to create heat and then using the heat to raise steam to drive turbines and generators, just like a conventional power station.
CSP is a practical technology with huge potential to supply Europe, the Middle East and North Africa (EUMENA) with plentiful, inexhaustible and secure supplies of clean electricity at competitive prices and on relatively short timescales:
Every year, each square kilometre of hot desert receives solar energy equivalent to 1.5 million barrels of oil. Multiplying by the area of hot deserts worldwide, this is several hundred times the entire current energy consumption of the world (see also map below).
The cost of collecting solar thermal energy equivalent to one barrel of oil is about US$50 right now (already less than the current world price of oil) and is likely to come down to around US$20 in future.
It is feasible and economic to transmit solar electricity to the whole of Europe via a low-loss HVDC Supergrid. But even without the Supergrid, the UK can start to benefit from solar power from North Africa via existing transmission lines. Reasons to build the Supergrid include: increased security of supplies, reducing wastage of renewable energy, smoothing variations in wind power, and in the transmission of large-scale but remote sources of renewable energy such as wave power.
A report (‘TRANS-CSP’) from the German Aerospace Centre provides detailed projections showing how CSP, with other technologies, can enable Europe to meet all its needs for electricity, make deep cuts in CO2 emissions, and phase out nuclear power at the same time.
Solar heat may be stored in melted salts so that electricity generation may continue at night and on cloudy days.
CSP plants have been operating successfully in California since 1985. The technology is described quite fully on the website of the US Department of Energy (www.eere.energy.gov/solar/csp.html).
CSP may be used to generate hydrogen, with many applications in a future ‘hydrogen economy’.
The TRANS-CSP report calculates that CSP is likely to become one of the cheapest sources of electricity in Europe, including the cost of transmission.
There is a range of techniques to ensure security of supply.
Plentiful and inexpensive supplies of clean electricity from CSP would open up many interesting possibilities for reducing CO2 emissions from transport and buildings: electrification of rail transport, plug-in hybrid electric vehicles (PHEVs) partly powered by green electricity, heating buildings using ground-source heat pumps powered by green electricity, and so on.
Apart from its enormous potential to supply EUMENA with clean energy, CSP promises other major benefits, especially in countries of the sun belt:
Waste heat from the generation of solar electricity may be used for the desalination of sea water. This can have a major impact in alleviating shortages of water, a problem that is likely to become increasingly severe with rising global temperatures.
The shaded areas under solar mirrors are protected against the harshness of direct tropical sunlight. They have many potential uses including horticulture using desalinated sea water. Thus land that would otherwise be unproductive can be brought into use.
CSP can become a large new industry, providing jobs and earnings throughout EUMENA.
By alleviating shortages of energy, water, food and usable land, CSP can reduce the risk of conflict over those resources.
A win-win solar collaboration amongst countries of EUMENA can help to improve relations amongst different groups of people.
CSP, with HVDC transmission, can have a major impact in decarbonising the world’s economy, providing large amounts of carbon-free electricity in several different parts of the world. All of the US demand for electricity could be met from CSP plants in the south western states, all of India’s needs could be supplied from the Thar desert and all of China’s electricity needs could be met from CSP plants in sunny parts of China.
These ‘DESERTEC’ ideas have been developed by the Trans-Mediterranean Renewable Energy Cooperation (TREC) and in the ‘MED-CSP’, ‘TRANS-CSP’ and ‘ AQUA-CSP’ reports for the German Aerospace Centre.
Further information, with links to those sources and others, may be found at www.trec-uk.org.uk and www.desertec.org.