The jet stream typically blows west to east, 6 to 9 miles over the northern hemisphere, at speeds up to 310 mph.
Wind machines could transmit electricity over aluminum or copper cables — or as microwave beams — to power grids. Atmospheric scientist Ken Caldeira at Stanford University says his calculations show that 1% of the energy in high-altitude winds could satisfy the world's energy needs. Scientists still need to identify materials that could stand up to the jet stream's buffeting, and find a way to reposition generators as the jet stream moves across the sky.