what is the significance of solar power i.e. wind, solar, and hydro?

Answer 1

solar, wind and hydro power are all environmentally friendly. they don't use up resources, they are renewable resources.

Answer 2

Lets not go crazy.. solar power at current is much more expenseive than raw fossil fuels because solar panals do not create very much energy atall.
Renewable energy sources are usefull and will have to become more widely used in the future since the earth will eventualy run out of resources in the future. (enless we steal them off a comet)
Wind power can be collected almost anywhere but it generaly msot effective out to sea where there will be "offshore windfarms" and on the top of hils.
Solar isnt particuraly good but its bieng used in parts of sub saharhan africa because romote places are not connected up to the "national grid" and cannot get electricity any other way. it is also used in other places to add to energy created by fossil fuels but not really.
Hydro power is pretty good, from dams etc.
Another one to add to your list, "bio fuels" where plants are growna nd the gasses they emit are caught and then burnt, alternatively cows farts can be caught and burnt in place of fossil fuels.
-Callipygian

Answer 3

Renewable-they are almost free, whereas oil needs to be drilled, and are depletable.