Hydrogen– hydrogen is a promising energy source. It is possible to generate energy from hydrogen by direct combustion or fuel cells.
Fusion energy – fusion of light elements like hydrogen can generate heat energy.
Cold fusion– It is a fusion reaction taken place in low temperatures.
Bubble power– it is similar to a cold fusion reaction. Hydrogen nuclei can fused together by tiny bubbles imploded by round water
Fuel cells– it directly converts chemical energy in a fuel to electrical energy without the application of burning.
Magnetohydrodynamic energy– MHD will convert thermal energy and kinetic energy directly in to electrical energy. This energy generator have no moving parts.
Osmotic power– it is also known as salinity gradient power. Power generation is possible when there is adequate difference in salt concentration.
Ocean thermal energy– there are ocean thermal energy converters which are used to produce power from the temperature difference between deep sea and surface.
Concentrated solar power– By using lenses concentrated solar energy can be used to generate power.