“Rising real prices of oil and natural gas reflect in part the progressive decline in low-cost reserves, and signal the wisdom of preparing now for a long transition from our petroleum-based economy. Almost certainly, future economies will exploit all possible technology options for replacing petroleum-based liquid fuels, especially technologies that do not produce net carbon dioxide, the major greenhouse gas. Biomass should, properly, be considered along with nuclear power and coal conversion with carbon capture and sequestration as important options for future energy supply.”