Since the Earth's cross sectional area is 127,400,000 km², the total Sun's power it intercepted by the Earth is 1.740×1017 Watts but as it rotates, no energy is received during the night and the Sun's energy is distributed across the Earth's entire surface area, most of which is not normal to the Sun's rays for most of the day, so that the average insolation is only one quarter of the solar constant or about 342 Watts per square meter. Taking into account the seasonal and climatic conditions the actual power reaching the ground generally averages less than 200 Watts per square meter. Thus the average power intercepted at any time by the earth's surface is around 127.4 X 106 X 106 X 200 = 25.4 X 1015 Watts or 25,400 TeraWatts.