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The province of Nova Scotia is moving forward with its plan to heat 6 public buildings using wood biomass instead of oil, and has identified a total of 100 provincial buildings suitable for this conversion (1). Exterior buildings containing boilers fueled by wood chips will be constructed to heat the selected sites (2). Though biomass is a renewable energy source that the European Union has declared as carbon-neutral, the question of whether this switch is a sustainable step forward is more controversial and confusing than expected.
Almost all of us have experienced biomass energy in one form or another - it is the burning of dead plant matter to create heat. While this is technically renewable, as trees that are cut down can be replanted, burning wood still creates CO2 emissions. Professor John Sternman, director of MIT’s Sloan Sustainability initiative, has spoken against the province’s plan and claims this switch will actually increase climate change and its impacts (3). He argues that when compared to coal, which is often considered to be the dirtiest fuel, biomass can actually be less efficient - therefore, in the short term, biomass will produce more emissions than coal to create the same amount of energy. This increase in emissions is referred to as 'carbon debt' (4). In his research, Sternman uses lifecycle analysis to show that biofuel is only carbon neutral if the short term carbon debt is eventually paid off by forest regrowth (4). Moreover, his paper highlights the risk of the additional CO2 contributing to irreversible impacts before it is captured and stored in carbon sinks, like forests (4).
Despite concerns that biomass fuel will increase greenhouse gas emissions, wood chips would provide a local energy source in Nova Scotia, and opportunities to utilize a relatively abundant resource. Unlike the UK, who has become the world’s largest wood pellet importer, in Nova Scotia wood is abundant locally, and emissions from transportation should be low (1). Additionally, economic opportunities for forestry operators is of increased importance due to the shutdown of the Northern Pulp paper mill in Pictou County (1). Ian Rankins argues that income from biomass combustion encourages woodlot holders to maintain their forests rather than clearing them for profitable residential or agricultural uses (3). Further, due to the closing of the paper mill the availability of wood chips in Nova Scotia has increased. While the mill was buying about 700,000 tonnes of wood chips each year the maximum amount needed for each heating plant is approximately 2,000 tonnes (2).
Considering the gap created by the closure of the Northern Pulp mill and the state of forestry in Nova Scotia, local history and social pressure will be extremely significant factors in the decisions surrounding the use of biomass. However, Canadians across the country may soon be faced with similar decisions. Biomass fuel and bioenergy have vague definitions that apply to all different kinds of plant-derived matter with varying efficiencies. For example, a study based in Saskatoon found that pinewood, wheat and flax straw have decent potential for bio-energy production (5). Since biomass is an abundant renewable energy source it is likely that similar proposals will increase across Canada. However, the ability of biomass fuel to be carbon neutral is increasingly questioned, as the possibility for forest regrowth is far from certain.
References
1: Gorman M. Province looks to wood as heat source for public buildings. CBC News. 2019. Available from: https://www.cbc.ca/news/canada/nova-scotia/forestry-clear-cutting-conservation-ecology-iain-rankin-1.5189312
2: Gorman M. Nova Scotia announces sites for 6 wood energy projects. CBC News. 2020. Available from: https://www.cbc.ca/news/canada/nova-scotia/forestry-government-projects-district-heating-wood-energy-1.5450146
3. Smith E. Burning biomass in N.S. will speed up the climate crisis, warns MIT prof. CBC News. 2020. Available from: https://www.cbc.ca/news/canada/nova-scotia/mit-john-sterman-woodchips-forestry-trees-nova-scotia-northern-pulp-1.5461404
4. Sternman JD, Siegel L, & Rooney-Varga JN. Does replacing coal with wood lower CO2 emissions? Dynamic lifecycle analysis of wood bioenergy. 2017. Environmental Research Letters. 13: 015007. DOI: 10.1088/1748-9326/aaa512
5: Satyanarayan N, Goud VV, Rout PK, Jacobson K, & Dalai AK. Characterization of Canadian biomass for alternative renewable biofuel. 2020. Renewable Energy. 35(58): 1624-1631. DOI: 10.1016/j.renene.2009.08.033