Which clements do plants need to grow?

I think bio-energy is not at all safe for us. Besides, it is causing environmental disasters, crop failure, soil and river erosion and other havocs. Moreover, excessive use of bio-energy paves the way for deforestation and all other deadly forms of climate.

Hydrogen in combination with oxygen makes water.

Hydrogen is always combined with other elements like oxygen. By separating hydrogen from another element, it can be burned as a fuel to produce electricity.

Geothermal energy is the thermal energy in the earth's crust which originates from the formation of the planet and from radioactive decay of materials in currently uncertain but possibly equal proportions.