The world's capacity to produce oil is still going up. Recent analyses, however, have estimated that the world oil reserves 8 will peak within the next 25 years 9 . Once the production capacity for world conventional oil starts a permanent decline, the price of oil will probably rise and a long-run substitute for the transportation sector will need to be put in place. It is important to analyze the economic and environmental implications of potential oil replacements. There is a growing scientific consensus that greenhouse gas 12 emissions could change the earth's climate.
Energy use is the biggest contributor of greenhouse gases, particularly carbon dioxide.
The transportation sector accounts for nearly a third of all U.S. greenhouse gas emissions, with passenger vehicles contributing the largest share . Advanced diesels also offer the potential for improved fuel economy, and are aimed primarily at trucks of all sizes. Potential Benefits from OTT Programs Estimates of energy savings, oil reductions, and carbon reductions are made each year and submitted to Congress as part of the annual budget process. Learn about PDFs . OPEC is the Organization of Petroleum Exporting Countries.