Stars remain as the Universe's top energy sources, only surpassed by those unknown areas in the center of galaxies. Being the Sun not particularly big in comparison with other stars with a radius of more than one thousand suns, its energy output is enough to vaporize Earth in seconds but fortunately it's far, far away.
Concretely an average distance of 150 million kilometers, thus the Sun's produced energy arrives Earth after approximately eight minutes and twenty seconds. And in that journey, there's not considerable loses because Space practically doesn't have anything in between to catch energy.
With an estimated age of four thousand six hundred million years, nobody could even imagine all the energy that was released since then and it has for several thousand million more! And for sure we should trust in the human intelligence for advancing until the last shiny sunrise.
Then, for answering the initial question, simply to remind here that there are basically two kinds of energies: those based in strong forces and the rest. Nuclear reactions are responsible for the matter itself, and the Sun takes benefit of that amazing quantity of released energy when hydrogen its converted to helium thanks to nuclear fusion, a strong force.
Besides, wise Nature always proves its superior intelligence with a very optimized method of amplification that ensures a blue sky for a long time. The surface of the Sun has only 5505 ºC, and some industrial ovens can reach 2000 ºC and more. But after some complex process, the temperature increases until millions of degrees.
Each second, the Sun converts more than five hundred tons of hydrogen in helium. This time carbon dioxide emissions in exchange are not the problem, but radiation in high frequency like UV, X-ray and gamma. Without atmosphere, the life here would be very difficult... a good reason to remember that it's necessary to keep it in optimal conditions.
Star energy is the exclusive choice for a truly developed specie. Because first, it's required to make it insufficient for thinking in other sources that create waste or pollution. The energy business should finally open the eyes and leave the air pollution to nightmares.