Magnesium Energy Cycle

There is no doubt that we need an energy cycle free of fossil fuels that otherwise emit greenhouse gases causing global warming. Although solar energy is the ultimate renewable energy source, it is far from fully realized. Furthermore, since sunlight is available only in the clear daytime, it cannot be an alternative to thermal power stations unless effective and large power storage systems are available.

Here we propose the chemical potential of magnesium as such an energy reservoir. Heat and hydrogen from the reaction of magnesium with water are used for turbines, reciprocal engines, fuel cells, and so on. The remaining "ash," MgO or Mg(OH)2, has to be deoxidized in order to make the energy cycle renewable. The deoxidization process is driven by the energy from a solar-energy-pumped laser, a laser diode powered by a wind-power generator, or other sources. Since laser radiation can be focused into a small spot, a very high temperature exceeding 4000 K, needed for MgO deoxidization can easily be obtained. Once such MgO deoxidization technology is developed, unsteady solar power can be stored in Mg form to provide a stable supply of energy.