Do you mean efficiency or energy dense? solar requires 2 acres to provide 1 MW electricity at peak sunshine, a natural gas conbined cycle power plant requires 37 acres to produce 550MW 24 hrs a day

Coal contains about the same amount of energy as petroleum, which is more than natural gas, but uranium contains the largest amount of available energy.

Renewable energy sources are the most efficient. While many people think of passive energy sources such as solar, wind and wave energy to be more efficient, there is too much energy lost in converting this type of energy to mechanical force. The most efficient energy source comes from biofuels or plant life. These are renewable sources with the ability to create ethanol or bio-diesel.

solar energy is one of efficient energy.

Efficient versus what? Modern plant photosynthesis is about 0.5% efficient in storing light energy as chemical energy, a small portion of that energy collected over millions of years and stored as fossil fuels by geologic forces and that's our primary energy source but how efficient is that, a fraction of a half a percentage...