Since 2005, the United States has embarked on a steady expansion of renewable fuels such as ethanol and biodiesel, widely touted as a win-win proposition for energy security and the environment. However, the promised breakthroughs in biofuel technology have greatly lagged the rapid ramp-up of production mandated by Congress while adverse side effects of the policy have become ever more clear.
With the backing of 13 car companies, the United Auto Workers and other parties, the Obama Administration announced the biggest step forward on auto efficiency in over a generation. The new Corporate Average Fuel Economy (CAFE) regulations just finalized target the greenhouse gas emissions equivalent of 54.5 mpg by model year 2025, double the efficiency of this year's vehicle fleet.
Building on the Bush Administration's 2007 proposal to raise automotive fuel economy by up to four percent per year, the Obama Administration is now considering regulations that might target a doubling of Corporate Average Fuel Economy (CAFE) standards by 2025. But just how much can the efficiency of cars and light trucks be improved, and at what cost?