Concentrating Solar Power (or CSP) is inefficient, expensive, and has notable environmental impacts.

Inefficient
According to the California Energy Commission ( http://www.energy.ca.gov/electricity/gross_system_power.html ), all of the utility-generated solar power in the state amounts to two-tenths of one percent of the state’s electricity production. Because of the limited availability of sunlight, these systems have notoriously low capacity factors and therefore cannot be relied upon for baseload power.

Expensive
According to the California Energy Commission ( http://www.energy.ca.gov/electricity/comparative_costs.html ), at 13 to 42 cents per kWhr, solar power is *the* most expensive way to generate electricity. In a time when energy prices are skyrocketing, few people can afford a large-scale conversion to solar power. What’s more, due to its low capacity factors, solar capacity must be backed up with additional stand-by power generation, which adds to the overall cost of solar.

Environmental impact
Solar collectors also require a huge area of land, which must be dedicated to solar generation. Even in the desert, this could disrupt the delicate ecology. Additionally, in order for the salts to remain molten at night, CSP requires fossil fuels to be burned for heat. According to a US Department of Energy study ( http://www.nrel.gov/docs/gen/fy98/24496.pdf ), these systems are “hybridized” with up to 25% natural gas. Ironically, this renewable technology is a contributor to greenhouse gas emissions!

Nevertheless, concentrating solar technology, along with many other renewable power sources such as wind, tidal, and geothermal, should continue to be supported in hopes that a breakthrough will someday allow them to be a significant source of energy generation. Today however, CSP is no replacement for baseload energy generation sources. In the medium term, we cannot abandon the proven, effective, and efficient source of low-emission energy that nuclear power has to offer. To learn more about the benefits of nuclear energy, check out http://www.nei.org/index.asp?catnum=1&catid=11 and http://www.casenergy.org/WhyNuclear/TheBasics/tabid/66/Default.aspx

Michael Stuart

Regarding the report “Iran to build two nuclear power plants”, there really is no need for nuclear power in the Middle East (or Europe or North Africa) because there is a simple mature technology available that can deliver huge amounts of clean energy without any of the headaches of nuclear power.

I refer to ‘concentrating solar power’ (CSP), the technique of concentrating sunlight using mirrors to create heat, and then using the heat to raise steam and drive turbines and generators, just like a conventional power station. It is possible to store solar heat in melted salts so that electricity generation may continue through the night or on cloudy days. This technology has been generating electricity successfully in California since 1985 and half a million Californians currently get their electricity from this source. CSP plants are now being planned or built in many parts of the world.

CSP works best in hot deserts and it is feasible and economic to transmit solar electricity over very long distances using highly-efficient ‘HVDC’ transmission lines. With transmission losses at about 3% per 1000 km, solar electricity may, for example, be transmitted from North Africa to London with only about 10% loss of power. A large-scale HVDC transmission grid has also been proposed by the wind energy company Airtricity as a means of optimising the use of wind power throughout Europe.

CSP offers substantial benefits to people in North Africa and the Middle East, including desalination of sea water using waste heat from electricity generation – a major benefit in arid regions. In addition, the shaded areas under the solar mirrors can be used for many purposes including horticulture using desalinated sea water. And of course, there would be plentiful supplies of inexpensive, pollution-free electricity and earnings from the export of that electricity to countries with less sunshine.

In the ‘TRANS-CSP’ report commissioned by the German government, it is estimated that CSP electricity, imported from North Africa and the Middle East, could become one of the cheapest sources of electricity in Europe, including the cost of transmission. That report shows in great detail how Europe can meet all its needs for electricity, make deep cuts in CO2 emissions, and phase out nuclear power at the same time.

Further information about CSP may be found at http://www.trec-uk.org.uk and http://www.trecers.net . Copies of the TRANS-CSP report may be downloaded from http://www.trec-uk.org.uk/reports.htm . The many problems associated with nuclear power are summarised at http://www.mng.org.uk/green_house/no_nukes.htm .