Diminishing reserves of cheap, recoverable crude oil, together with increasing tensions between the Middle East and the West, will likely threaten our access to affordable oil in the future. Alternative fossil fuels such as coal, tar sand, and heavy oil will only worsen global warming. Hydrogen, however, is plentiful and clean, stores energy more effectively than batteries, burns twice as efficiently in a fuel cell as gasoline does in an internal-combustion engine, leaves only water behind, and can power cars. But many challenges remain before fuel cells will replace oil and other fossil fuels. Overcoming these challenges requires a deep understanding of the components' microscopic structure, detailed analytical information about how the various components interact, and the ability to predict how the components will perform under load conditions. To solve these problems, materials scientists are turning to knowledge management techniques, particularly Semantic Web technologies, to make sense of and assimilate the vast amounts of microstructural, performance, and manufacturing data that they acquire during their research.