You don't "turn" it into energy; petroleum HAS stored energy (chemical energy).However, you can turn it into ANOTHER TYPE OF ENERGY; usually this is done by burning the petroleum, and using it to drive machinery.
Since burning fuels is wasteful (the efficiency is limited, in theory, to the Carnot efficiency of a heat engine), other options are being explored, such as chemical reactions in a fuel cell. But such technology is not yet used on a large scale.
O,P,Ge ranked from atomic radius
When HCl reacts with a metal, hydrogen gas will be evolved. To test this gas, insert a burning splinter into the outlet of gas, the flame will be extinguished with a pop sound. This will confirm the gas is hydrogen.
Of the three sources listed, geothermal energy
is the least dependent on the weather.
(Once it's installed and running, that is.)
The best answer that I can give you is, the Plate.
