Technology dynamics and greenhouse gas emissions mitigation: A cost assessment

This article analyzes long-term greenhouse gas (GHG) emissions and their mitigation in a family of high economic and energy demand growth scenarios in which technological change unfolds in alternative ''path dependent" directions. Four variants of this family are developed and used as baseline scenarios, for which alternative policy cases leading to stabilization of atmospheric CO2 concentrations at 450, 550, 650, and 750 parts per million by volume (ppmv) by the end of the 21st century are examined. The baseline scenarios share common demographic, economic, and energy demand developments, but explore alternative development pathways of technological change and resource availability. We illustrate the sensitivity of projected future GHG emission levels and resulting global climate change to alternative developments in energy systems technologies. We conclude that uncertainties in technological change are as important for determining future GHG emissions as uncertainties in long-term demographic and economic developments. We also illustrate that differences in costs between alternative baseline scenarios of technological change may be larger than the cost differences of reaching alternative environmental (climate change stabilization) targets. Under our assumptions of high economic and energy demand growth, even in scenarios favoring fossil fuels, the longterm technology portfolio needs to include improvements in zero-carbon technologies and gas-related technologies and infrastructures. We suggest that improvements in these technology options are a robust hedging strategy for an uncertain energy future. (C) 2000 Elsevier Science Inc.