Earth intercepts only a tiny fraction of all of the energy coming off the Sun but it’s enough to bathe our planet in radiant light and warmth to the tune of about 55 x 10 joules each year. That means that our estimate of the civilizational energy usage to meet the needs of every human on Earth is about 0.04 percent of the inci dent solar radiation (which also powers the movement of wind and water on the planet). Four parts in ten thousand.