The core of the Sun is at such extreme temperature and pressure that in that core hydrogen atoms are constantly fusing into helium and giving off massive amounts of energy. The Sun fuses about 4.25 million metric tonnes of hydrogen every second, which provides a power generation of 3.8 x 10^26 watts. By contrast, the largest power plant on Earth right now is the Three Gorges Dam in China, which produces 2.25*10^10 watts of power. That means that the sun produces more than 1.68 x 10^16 times the energy than the largest power plant on the planet.
That energy is given off by the sun in the form of heat and light that provides a great deal of the available energy on Earth. The solar energy that reaches the surface of the Earth is equal to about 1 kW/m^2. The average American home uses about 901 kWh per month, or about 1.2 kW average power use, which means that (at 100% efficiency) the average home could be powered with just over 1 square meter of solar panels.
That incoming energy is not only utilized by our solar panels, but also by our plants, and by our atmosphere. Our atmosphere is heated by the Sun’s rays, and our plants are fed by the Sun as well. Those plants in turn feed our animals, and our people. The Sun provides all of the energy to sustain life on Earth, and that’s only a small fraction of the energy the Sun produces.