The Sun, the energy of the tomorrow
Fossil fuel reserves may cover, altogether, the global energy demand for the next 96 years (nuclear energy: 12 years; natural gas: 13 years; oil: 15 years; coal: 56 years).
Some renewable energy sources (waves, biomass, hydro, geothermal) can cover only part of our annual energy needs.
The Sun is our biggest hope.
Being an energy source that is 1500 times higher than our annual consumption, the sun is able to sustain the entire human community, provided that we develop the necessary infrastructure to capture, store and use its energy. And even more important, provided that we build a more environment oriented social and political mindset.