In China, one doesn't have to look far to see the country's commitment to renewable energy. In cities such as Beijing and Shanghai, rooftops are now covered with solar water heaters. On the grasslands of Inner Mongolia, towering white wind turbines are popping up where only cattle, sheep and herders on horseback once roamed. While coal consumption is expected to climb more than 3% annually for the next two decades, the government has also required that electrical companies add a significant amount of alternative energy to their portfolios. With the global economy languishing, China — which is not only the world's most populous country, but also the most polluted — offers the promise that its green-energy drive can become a major source of demand for international wind and solar companies.