The following are primary sources of energy
1. Sun
2. Fossil fuels
3. Hydro electric power
4. Wind power
5. Tidal power
6. Nuclear power
In the strict sense, even 2 to 5 are secondary which got energy indireclty from the sun, but for all practical purposes they can be considered as independent primary sources since man has no role in convering the solar energy to that.
All other sources are secondary fuels. Examples are:
1. Hydrogen (we need one of the above to supply energy to split water)
2. Battery (we need electricity produced by one of the above to charge it)
3. Compressed air (we need energy from one of the above to operate the compressor).
There is some research going on to find a method to directly split water and generate hydrogen from sunlight instead of the expensive two stage method of converting sunlight to electricity using solar panels and then using the electricity to split hydrogen. But hydrogen has some practical issues like saftey, difficulty in storing etc.
Tomy
|
