A life cycle evaluation of wood pellet gasification for district heating in British Columbia Ann Pa a , Xiaotao T. Bi a,⇑ , Shahab Sokhansanj a,b a Clean Energy Research Centre for University of British Columbia, 2360 East Mall Vancouver, BC, Canada, V6T 1Z3 b Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA article info Article history: Received 23 November 2010 Received in revised form 28 January 2011 Accepted 1 February 2011 Available online 5 February 2011 Keywords: Life cycle analysis (LCA) Wood pellets British Columbia District heating Gasification abstract The replacement of natural gas combustion for district heating by wood waste and wood pellets gasifi- cation systems with or without emission control has been investigated by a streamlined LCA. While stack emissions from controlled gasification systems are lower than the applicable regulations, compared to the current base case, 12% and 133% increases are expected in the overall human health impacts for wood pellets and wood waste, respectively. With controlled gasification, external costs and GHG emission can be reduced by 35% and 82% on average, respectively. Between wood pellets and wood waste, wood pellets appear to be the better choice as it requires less primary energy and has a much lower impact on the local air quality. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction As climate change due to greenhouse gas (GHG) emissions is gaining recognitions, various methods of climate change adapta- tion and GHG emission mitigation have been proposed, discussed and explored. Replacing a fraction of the current fossil fuel by alternative energy sources such as bioenergy is one of the many approaches recommended by policy makers. For instance, ethanol blending requirement in transport fuel in the United States reaches 1.14 EJ in 2010 and will increase to 3.18 EJ by 2022 while the European Union target for renewable energy in the transport sector in 2020 is set to 10%, or 1.29 EJ of biofuel (IEA and OECD, 2009; European Commission, 2007). Other than in the transport sector, there are numerous studies that emphasize the potentials of renewable energy, or more specifically bioenergy, in district or residential heating and in combined heat and power systems (CHP) (Difs et al., 2010; Björklund et al., 2001). The importance of policy developments to promote the use of bioenergy in these sectors is also discussed (Kopetz, 2007; Rickerson et al., 2009). However, the use of biomass for district heating has been quite controversial due to concerns with possible increase in health im- pact (Ries et al., 2009). This concern is especially true when the fossil fuel to be replaced is natural gas and when the community is densely populated. There are currently a few major district heating systems in Vancouver. These include one located in the stadium and entertainment district in the core of downtown (Davis, 2004) and three in Vancouver’s largest hospital sites (Roger Bayley Inc., 2009; Ministry of Energy of British Columbia, 2010). The most recent establishment is the Southeast False Creek Neigh- bourhood Energy Utility (NEU) which provides hot water and heat for all new buildings in the area, including the Olympic Village that was built to accommodate Olympic athletes participating in the 2010 Winter Olympic (City of Vancouver, 2010). The downtown system operates on natural gas while the NEU operates on a base-load system utilizing sewer heat recovery pump along with a natural gas peaking/back-up boiler. There was a debate at the beginning on the energy source to be chosen for the base-load sys- tem and the two contenders were biomass and sewer heat (Roger Bayley Inc., 2009). In the end sewer heat recovery heat pump sys- tem was selected because of the public concerns on local air qual- ity and traffic inconvenience that may arise from biomass utilization. Another district heating system in Vancouver is at the Univer- sity of British Columbia (UBC), where more than 99% of the heat is generated from natural gas and the rest from fuel oil during peak season. With UBC’s ambitious plan of reducing GHG to 33%, 67% and 100% below the 2007 level by 2015, 2020 and 2050, respec- tively, the University has devised a detailed plan of action. Replac- ing natural gas with renewable energy is an important part of the actions to be taken (University of British Columbia, 2010a). In fact, $26 million CAD has been allocated for the establishment of a bio- mass gasification cogeneration system on campus for research and 0960-8524/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2011.02.009 ⇑ Corresponding author. Tel.: +1 604 822 4408; fax: +1 604 822 6003. E-mail address: xbi@chbe.ubc.ca (X.T. Bi). Bioresource Technology 102 (2011) 6167–6177 Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech