China’s wild binge of solar manufacturing drove down the costs of solar panels, both by oversupplying the market and by hastening economies of scale. In effect, the country voluntarily took on the costs of pushing solar panels onto the “S-curve” of rapid growth, a strategy that will greatly benefit the Chinese—and the rest of humanity. Now there’s evidence that China is in the midst of doing the same thing for another key clean-energy product: electric buses. China has already electrified entire fleets of buses in some of its cities, and if costs keep plummeting, we could start seeing this happen in other cities around the world.