Sure enough, the technology offers a lower energy intensity than fossil or nuclear energy sources, but Mr Smil admits that the power density of solar is 20 times that of biomass and twice as high as hydro or wind power. So, why not put more emphasis on solar?
For Mr Smil, the main drawback is in the area of land that would have to be covered in solar panels to meet our current energy needs. For instance, the area of panels needed to supply a supermarket would be 10 times the size of the roof area.
It is likely this fact that prompts R. Cleirigh's letter that renewable energy sources on a micro-scale to supply communities and villages is a solution (No 262, July 2007). But is the public aware that major solar power stations now on the horizon barely take up more space than conventional electricity stations?
In fact, one coming onstream in 2008 near Grenada in Spain will be the world's largest, generating some 50 MW to supply electricity to some 45,000 homes. Soon after another even bigger 62 MW station will come onstream in Moura, Portugal.
Beyond panels there are other sources of solar-generated power, such as thermodynamic steam turbines with a high energy intensity not far off that of coal or oil. A major project using this procedure is under way in Sanlùcar la Mayor, near Seville, with a target supply of over 150,000 households. There is also one based in Germany. Finally, might I add that NASA has been working on a project to put solar panels in space with a view to supplying millions of consumers on the ground. Space might not be a problem after all.
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©OECD Observer No 263, October 2007