The biomass dilemma: Assessing synergies and trade-offs between climate change mitigation, air quality and other environmental impacts across the EU

While climate change mitigation strategies across the EU have often promoted the use of wood-based biomass for heat and power supply to reduce the use of fossil fuels, its actual benefits are unclear. The use of wood-based biomass can pose risks to air quality and health, especially when used in small-scale heating systems in cities. To leverage synergies and avoid trade-offs between climate change mitigation, air quality and other environmental impacts, policymaking should be supported by integrated quantitative analyses. This article presents a novel life-cycle assessment framework to calculate the potential environmental impacts of wood-based biomass use in small-scale residential heating systems, for a wide range of impact categories. The framework is applied to (i) the assessment of current wood-based biomass heating impacts across 23 EU Member States and 87 cities and (ii) two illustrative scenario analyses for five countries evaluating environmental trade-offs and co-benefits of energy-related measures. The results for climate change (CC) and particulate matter (PM) show that (i) small-scale solid wood-based biomass systems still pose significant risks to air quality and public health, with limited (and uncertain) CC benefits; (ii) higher-efficiency heating systems may reduce PM trade-offs, but their CC benefits are limited due to supply chain impacts; and (iii) large-scale heating systems, such as district heating, can offer larger environmental benefits than small-scale systems. A complementary analysis shows that the results for PM are generally underestimated and overlook the variability of health effects resulting from air pollutant emissions across cities. The framework is widely applicable and, complemented with case-specific data, it can provide relevant results to inform policymaking at multiple geographical and institutional scales. • An environmental impact assessment framework to support cities is presented. • The framework addresses life-cycle impacts of biomass-based residential heating. • The framework is applied to 87 EU cities in 23 countries and to two scenario analyses. • The results show a strong correlation between GHG and air pollution impacts. • Scenarios show high variability in co-benefits and trade-offs of GHG mitigation.