When Chinese president Hu Jintao visited the United States this month, many issues made headlines, but one that didn’t is nonetheless important: clean energy cooperation, competition, or both. This issue is a litmus test for the two superpowers’ ability to build a partnership based on mutual needs and opportunities. The outcome will affect our global economic, environmental and geopolitical future, and may influence the range of clean energy opportunities for emerging economies in fundamental ways.

The two countries need each other to build the clean energy economy. China needs energy to grow, and can drive the exponential growth needed to move renewable energy to the center of the global energy system. The U.S. has a nimble and deep research and development system, and serial