Coal may provide a potential new way to store hydrogen gas, much like batteries store energy for future use, addressing a major hurdle in developing a clean energy supply chain, according to a study. Hydrogen is a clean burning fuel and shows promise for use in the most energy intensive sectors of the economytransportation, electricity generation and manufacturing, the researchers said. However, much work remains to build a hydrogen infrastructure and make it an affordable and reliable energy source, they said. This includes developing a way to store hydrogen, which is currently expensive and inefficient.