How much energy is released by the sun per second?

The sun releases 27*10²³ KW energy per second. 

The sun generates energy from a process called nuclear fusion. During nuclear fusion, the high pressure and temperature in the sun's core cause nuclei to separate from their electrons. Hydrogen nuclei fuse to form one helium atom. During the fusion process, radiant energy is released.There is a reason life that Earth is the only place in the solar system where life is known to be able to live and thrive. Granted, scientists believe that there may be microbial or even aquatic life forms living beneath the icy surfaces of Europa and Enceladus, or in the methane lakes on Titan. But for the time being, Earth remains the only place that we know of that has all the right conditions for life to exist.

The simple answer is that the sun, like all stars, is able to create energy because it is essentially a massive fusion reaction. Scientists believe that this began when a huge cloud of gas and particles (i.e. a nebula) collapsed under the force of its own gravity – which is known as Nebula Theory. This not only created the big ball of light at the center of our solar system, it also triggered a process whereby hydrogen, collected in the center, began fusing to create solar energy.