Net environmental impacts of low-share wood pellet co-combustion in an existing coal-fired CHP (combined heat and power) production in Helsinki, Finland

• Published in: Energy (Oxford) 2014-12, Vol.77, p.844-851
• Main Authors: Judl, Jáchym, Koskela, Sirkka, Korpela, Timo, Karvosenoja, Niko, Häyrinen, Anna, Rantsi, Jari
• Format: Article
• Language: English
• Subjects: Air pollution caused by fuel industries; Air quality; Applied sciences; CHP; Climate; Climate change; Combined heat and power; Combined power plants; Energy; Energy. Thermal use of fuels; Environmental impact; Environmental impacts; Exact sciences and technology; Fine particles dispersion model; Hot spots; Installations for energy generation and conversion: thermal and electrical energy; Pellets; Pollution reduction; Screening LCA (life cycle assessment); Wood; Wood pellet co-combustion
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2014.09.068

The EU's energy sector depends heavily on fossil fuels, which contribute to climate change. This is why climate mitigation targets for energy production have been set, including an increased biomass use requirement. In Finland, biomass is commonly utilised but its capital, Helsinki, is still dependent on fossil fuels. With the ambition of becoming climate neutral by 2050, Helsinki is testing, inter alia, low-share wood pellet and coal co-combustion in a CHP (combined heat and power) plant. The objectives of this paper were to assess the net environmental impacts of the co-combustion and changes in urban air quality connected to pellet transport, and to identify environmental hotspots relevant to possible future higher-share co-combustion. The applied methods were screening LCA (life cycle assessment) and fine particle dispersion modelling. The results prove that low-share wood pellet co-combustion in CHP production leads to net environmental impact reductions and does not deteriorate air quality in the urban environment. If higher-share co-combustion were to be implemented, the environmental hotspots to focus on would be the operational issues of a power plant and the origin and sustainability aspects of wood pellet production. •Low-share wood pellet co-combustion in coal-fired CHP (combined heat and power) production was studied.•Co-combustion of pellets made of sawdust decreases environmental impacts.•Additional wood pellet transport does not compromise urban environment air quality.•Higher share co-combustion will have an effect on operation of power plant.•Sustainability aspects of wood pellet production must be taken into account.