coal
the petroleum is used as fuel. it is burned, letting out a burst of energy
Solar energy is indeed a useable source of power. There are many companies and businesses that use solar energy as an alternative power source to other energy sources such as oil or fuel.
The sun is the ultimate source of all energy in Earth's ecosystems.
"Free fuel" They both utilize solar energy.
No. It can be an energy source, but it's not a fuel.
Chemical energy
No it is its own source of energy
Currently, human's conventional source of energy is fossil fuel.
Petroleum is the main source of energy for transportation.
It is a source of energy. Meaning that we can drill for it and then we have it, we don't have to create it. On the other hand hydrogen fuel has energy, but it isn't a source of energy because we can't simply drill for it, instead we have to create it. So while oil is a source of energy, other energy storing compounds like hydrogen fuel are not fuel sources.
i may not be right, but the energy source should be fossil fuel
Cells do not choose their source of energy.
Hydrogen is not a renewable fuel. It is a secondary energy source (or an energy carrier) that could be produced using another primary energy source. Hydrogen could be produced using either renewable primary energy source (e.g. solar energy), nuclear energy, or by using fossil fuel (e.g. natural gas)
synthetic fuel is renewable
coal was the main source at that time
Cheap source of energy