Evaluations of Domestic Applications of British Columbia Wood Pellets based on Life Cycle Analysis

Ann Pa*, University of British Columbia
Jill Craven, Clean Energy Research Centre, University of British Columbia
Tony Bi, University of British Columbia
Staffan Melin, elta Research Corporation, Delta, Canada
Shahab Sokhansanj, Chemical and Biological Engineering Department, University of British Columbia and Environmental Sciences Division, Oak Ridge National Laboratory

A LCA database for British Columbia wood pellets has been developed. Currently about 80% of the pellets produced in BC are exported to Europe. Based on the database, marine transportation is responsible for 45% of the life cycle energy consumption and is the top contributors to most pollutants investigated. Exported pellets have an energy penalty of 33% while non-exported pellet’s value is only 18.3%. Exported pellets’ energy value contains 22.2% fossil fuels but non-exported only contains 7.5%. It is evident that wood pellets can be even greener if utilized in BC. Based on this finding, two case studies exploring possible domestic usage of wood pellets are carried out using the LCA database.

The first case looks into the change in environmental impacts and health impact potential (HIP) if UBC boiler house, which currently runs on natural gas 99% of the time, was to be fueled by wood pellets. The environmental impacts evaluated are global warming potential (GWP), acid rain formation potential (ARP), and smog formation potential (SFP). The proposed pellet system consists of pellet gasification followed by the combustion of the syngas produced.

The result indicates that GWP of the operation can be reduced by 70% if pellets are used but ARP will increase by approximately 285% while SFP may increase by 185%. This result is based on a streamlined LCA including all fuel production and transportation. To investigate the change in HIP, only the actual end usage emissions are included in the evaluation. The HIP increases by 285% from 24.07 to 92.67 for switching to pellets and the increase is 227% when an electrostatic precipitator unit is installed.

The second case looks into the change in emission in BC if the current residential log-burning furnaces are replaced with pellet stoves. In addition to the quantification in the reduction of air emissions, a simple cost analysis is also carried out to evaluate the economic feasibility of this proposal. The result of cost analysis will also aid the local government in the development of an incentive program to promote the switching of current log furnaces to wood pellet furnaces in BC.

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