The Economic and Environmental Consequences of Automobile Lifetime Extension and Fuel Economy Improvement: Japan's Case

The present paper develops a structural decomposition analysis with cumulative product lifetime distributions to estimate the effects of both product lifetime shifts and energy efficiency changes on the embodied energy consumptions. The empirical analysis focuses on automobile use (ordinary passenger vehicles, small passenger vehicles, and light passenger vehicles) in Japan during the period 1990-2000. It reveals that the lifetime extension of existing old vehicles during the study period was more beneficial to the environment than purchasing new passenger vehicles with a relatively high fuel economy, because the lifetime extension empirically contributed to reducing the embodied energy consumption at the production and end-use stages. We also found that the energy-saving impact of a one-year lifetime extension was approximately 1.3 times larger than that of the most significant technological improvement in the electric power generation sector.