Clean power from deserts

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CONCENTRATING SOLAR thermal POWER


"CSP may do for fossil fuels what DVD did for VHS" - Chris Mason


Enormous quantities of energy fall as sunlight on the world’s sunny deserts and ‘concentrating solar thermal power’ (CSTP) is a proven technology for tapping in to it (see, for example, the website of the US Government's Department of Energy at www.eere.energy.gov/solar/csp.html). This is not some futuristic possibility like fusion nuclear power. CSTP is a relatively simple, mature and practical technology that, with the right political and financial impetus, can be brought into play very soon.

CSTP comes in four main variants:

Click each image to enlarge it xx   'Power towers' use a large field of sun-tracking mirrors to concentrate sunlight on to a receiver on the top of a low tower, to raise steam and generate electricity.
  xx   'Trough systems' use parabolic trough-shaped mirrors, each one of which focuses light on to a tube containing oil or similar fluid that takes the heat to where it can be used to raise steam and generate electricity.
  xx  

Fresnel mirror systems are similar but use long flat mirrors at different angles to concentrate sunlight on to a tube containing heat-collecting fluid. In some variants, sunlight is concentrated on to PV panels. The School of Physics, University of Sydney, has published an article discussing some of the advantages of this kind of system and aspects of its design.

xx Click to enlarge

  xx   Each 'dish/engine' system uses a large sun-tracking mirror with a Stirling engine generator at its focal point to convert heat energy into electricity. Sometimes, photovoltaic (PV) panels are used to convert the concentrated sunlight to electricity (see "Solar technologies" and "Australia plans major solar plant"). And sometimes Fresnel lenses are used instead of mirrors to concentrate sunlight onto PV panels.

On a separate page, there is a brief explanation of how the parabolic trough version of CSP works.

In CSTP plants, the heat can be stored in melted salts (eg nitrates of sodium or potassium), and gas or biofuels may be used as a backup source of heat, so that electricity generation may continue at night or on cloudy days (see below).

Systems like these can be installed in large numbers as 'farms' in deserts and other sunny areas. With economies of scale, concentrating solar power is likely to be very competitive on cost (see How much will it cost?). There is a nice fit between wind power in northern Europe, which is greatest in the winter, and solar or wind power from North Africa and the Middle East, which is greatest in the summer.

A report from the German Aerospace Centre shows how, even allowing for increases in demand, a combination of CSTP with other technologies can enable Europe to cut CO2 emissions from electricity generation by 70% by the year 2050, and phase out nuclear power at the same time. This 'TRANS-CSP' report (and the associated AQUA-CSP and MED-CSP reports) can be downloaded via links from www.trec-uk.org.uk/reports.htm.

Every year, each square kilometre of desert receives solar energy equivalent to 1.5 million barrels of oil. Multiplying by the area of deserts world-wide, this is several hundred times the entire current energy consumption of the world.

Using CSP, less than 1% of the world's deserts could generate as much electricity as the world is now using. It has been calculated that 90% of the world's population lives within 2700 km of a desert and could be supplied with solar electricity from there.

The cost of collecting solar thermal energy equivalent to one barrel of oil is about US$65 right now and it is likely to come down to around US$26 in future.

New CSTP plants are now being planned, built or are up and running in many places around the world. The ones we know about can be seen on Google Earth, with links back to our News page.


Desertec power is clean, safe, plentiful, inexhaustible, globally distributed, technologically proven, quick to build, dispatchable (available on demand), not dependent on scarce materials or dwindling supplies of fuels, with a good EROEI,note1 and likely to become one of the cheapest sources of electricity.note2 Few other sources of power have so many positive features.

note1 “Energy Return on Energy Invested.” The energy payback time for CSTP plants is about 6 months.

note2 The TRANS-CSP report from the German Aerospace Centre (DLR) calculates that CSTP in desert regions is likely to become one of the cheapest sources of electricity throughout Europe, including the cost of transmission.


Getting the energy to where it is needed (click for more information)

It is feasible and economic to transmit solar electricity to the whole of Europe, the Middle East and North Africa using modern high-voltage DC (HVDC) transmission lines. Solar power may also be transported as hydrogen.

Generating electricity without the sun (click for more information)

Solar heat can be stored so that electricity generation may continue through the night and on cloudy days.

How much will it cost? (click for more information)

CSTP electricity is likely to become one of the cheapest sources of electricity, including the cost of transmitting it over long distances.

CSP around the world (click for more information)

At least 90% of the world's population may be supplied with clean electricity from CSP plants in deserts around the world. There is great potential for cutting worldwide CO2 emissions from electricity generation.

Security of supply (PDF, 45 KB)

CSP can provide greater security of supply than our current main sources of energy.

CSTP bonuses (click for more information)

CSTP can yield much more than plentiful, inexhaustible, and secure supplies of pollution-free electricity. A major attraction of these benefits is that, unlike money derived from oil, most of them are of a kind that will be a direct benefit for local people and cannot easily be hijacked by others.

Desertec and industrial processes (click for more information)

CSP can, in principle, provide the large amounts of energy needed to produce things like aluminium, steel, cement, or synthetic fuels.

How CSTP works (click for more information)

Click the title for a brief explanation of how CSTP works, as mentioned above.

How to minimise the use of water in CSP plants (click for more information)

CSTP works best in sunny deserts where there is not normally much water but there are ways of minimising the use of water that is normally required for steam generation, for cooling and for cleaning solar mirrors.

How clean solar power may replace dirty kinds of power (click for more information)

Given plentiful supplies of clean clean solar power, there is scope for replacing dirty sources of energy in transport by rail and road, in the use of synthetic fuels, and in space heating for buildings.

Other questions about CSP (click for more information)

This section provides brief answers to some other questions that are asked about CSP, such as how CSP plants cope with sandstorms, the materials needed to build CSP plants, their environmental impact, and more.

Links

CSP resources

Click the heading for links to leaflets, a slide show, a display on Google Earth showing CSP plants around the world, and other information.


Last updated: 2012-06-04 (ISO 8601)