It’s 0%. Solar radiation is about 1.4kW per square meter. We use a fraction of the sun’s total energy output each year, orders of magnitude more energy are in

It’s 0%. Solar radiation is about 1.4kW per square meter. We use a fraction of the sun’s total energy output each year, orders of magnitude more energy are in sunlight radiating onto the Earth than in the heat rejected from buildings with air conditioning.