Methods in environmental assessment of renewables

Paper i proceeding, 2015

All energy systems carry environmental impacts and given the threats of global warming, fossil-based energy systems need to be substituted. It is also important to reduce the environmental burdens of greenhouse gases without increasing other environmental impacts. To prevent burden-shifting, assessments of the environmental performance of different renewable sources become crucial. Ideally methods are able to cover a number of fundamentally different energy systems and able to consider environmental impacts along the entire life-cycle of the energy systems, while maintaining comparability across system types. Methods can also handle specific technical designs, locations and scales of installations since they are factors determining environmental impacts. These site-specific factors cannot be fully assessed in a standardised manner, so there is a need for assessment methods adaptable to the specific case. Requirements on methods give a long wish-list. Here we report on a framework, applicable on renewable energy systems, that combine life-cycle thinking and an ecological risk assessment approach with examples of stressors, endpoints and environmental indicators. We also illustrate the relationship between the non-site specific life-cycle approach and the more site-specific environmental impact assessments and discuss the complementarity of the methods using an example of Scandinavian renewable energy systems. Furthermore assessments need to support trade-offs. It may however be fair to perform simple between-technologies-comparisons only with specific parameters. Other important aspects of the energy systems will fall in a category of incommensurable variables. A framework, combining life-cycle thinking and environmental risk assessment approaches, is presented and the relationship between non-site dependent and site-dependent methods is exemplified using some Scandinavian renewable energy systems.