LETTER AS SUBMITTED TO THE NEW SCIENTIST

Dear Editor,
The use of powdered metal (iron, aluminium etc) or boron as fuel for various kinds of engine ("The New Iron Age", NS, 22 October 2005) suggests a 
possible solution to another problem: how to tap in to the enormous quantities of energy falling as sunlight on the world's hot deserts.
Sunlight can be concentrated with mirrors to raise steam and generate electricity (www.eere.energy.gov/solar/csp.html) but centres of population, 
where the energy is needed, are typically a long way from where there is most sunlight. Conduction losses mean that it is not economic to transmit 
electricity directly over long distances and, while hydrogen may be generated by the electrolysis of water and used as an energy vector, it is 
awkward to handle and expensive to transport by tanker or pipeline.
If, as suggested in "The New Iron Age", powdered metal or boron can be produced by treating the relevant oxide with hydrogen (or if these things 
can be made directly from the oxide using the energy of concentrated sunlight), then they may serve as a very convenient medium for transporting 
solar energy to the places where it is needed. The oxide produced when the metal or boron powder is burned may be collected and returned to the solar 
power plants for recycling.
Sincerely,
Gerry Wolff
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