LCA-based evaluation of ecological impacts and external costs of current and new electricity and heating systems

Abstract

AbstractA systematic study of current European electricity and heat systems performed in the frame of the Swiss LCA project ecoinvent was extended to a few new technologies and used as a basis for comparison and ranking using External Costs Assessment and one selected Life Cycle Impact Assessment (LCIA) method. The energy systems include full process chains from extraction of resources through waste disposal. The external costs from airborne emissions were estimated using the most recent findings of the ExternE series on the average damage factors for Europe.Current fossil electricity systems exhibit the highest LCIA scores as well as the highest external costs, unless greenhouse gas emissions (GHG) are valued very low (sensitivity) and advanced technologies are applied. Alpine hydropower always exhibits the lowest score. Environmental performance of current renewables is generally better than fossil but LCIA ranking for wind and PV may worsen when increased importance is attributed to abiotic resource depletion. Wood cogeneration has a relatively poor score compared to other renewables. Nuclear shows generally good environmental performance, unless the high radioactive wastes are given subjectively high negative value. For heating systems, oil has higher external costs than natural gas, with conventional wood in between. External costs of heat pumps strongly depend on the origin of the electricity supplied.Sensitivity analyses were performed for external costs to reflect uncertainties of impacts and variations in monetary valuation. Fossils remain worst performers. External costs of nuclear remain low. Using allocation by exergy, electricity by diesel and natural gas cogeneration ranks worse than oil and natural gas combined cycle, respectively, and never better than renewables or nuclear.