OK
Electricity from solar panels - fuel? Hydrogen etc - nuclear fusion in the Sun
Electricity from wind - fuel? as above, solar energy causes wind and weather
Electricity from hydro schemes - fuel? As above, solar radiation causes evaporation/precipitation/rivers etc
Electricity from batteries - fuel? Chemicals in the batteries
Electricity from fossil fuel power stations - fuel? combustible hydrocarbons or coal
Electricity from nuclear power station - fuel? fissile materials refined from minerals extracted from the ground.
Electricity in your petrol/diesel car - fuel? Petrol or diesel.
Simple really. ::)
The fuel is what is CONSUMED or CONVERTED from one state to another in order to create controllable energy, which is then usually used to turn an induction device (the alternator in your car for example) to create electrical current. In the case of the solar panels, hydro, or wind systems, the fuel happens to be consumed 93 million miles away.