Energy needs and sustainable management of the energy cycle

The issue of sustainability of the energy policies is analised in its manifold facets. An overview is given about the trend of global energy needs and energy production, analysing the geographic distribution of consumptions and the share of energy sources, on the basis of the statistics and projections published by major agencies. The issue of sustainability of the energy cycle is finally addressed, highlighting how the use of biomasses as an energy source and of hydrogen as an energy carrier are among the most promising approaches.