Cooperation on clean energy could be a high point in U.S.-China relations leading to benefits for both countries, government and business officials said ahead of a summit between Chinese President Hu Jintao and President Barack Obama. Disputes between the world's two largest economies and energy consumers over China's wind power subsidies and its slowdown in exports of rare earths minerals, used in everything from wind turbines to cell phones, have dominated headlines in recent months. As China tries to transform its economy from the manufacturing of cheap goods into one developing and distributing sophisticated technologies, such as clean energy, spats over intellectual property rights have already troubled trade relations between the two countries. But pressure on both countries to reduce greenhouse gas emissions and reel in fossil fuel demand may push them to overcome these differences.