Achieving decarbonization using forest-based bioenergy

Declining trends in the forest industry market provide incentives to develop new products and processes. The climate change mitigation potential of forest products adds further incentives. Forest-based bioenergy is one such product that has attracted attention, primarily because it usually has a lower carbon balance than its fossil counterparts. Many countries including Canada have announced ambitious plans to reduce their GHG emissions following national or international commitments like the Paris Agreement. Likewise, the province of Quebec—used as a case study—plans to achieve net-zero emissions by 2050 through various means, such as increasing bioenergy production. Forest-based bioenergy is a storable energy solution, is compatible with the existing fossil infrastructure, does not threaten food security, and is more socially acceptable to the Canadian people. Moreover, in the province of Quebec, it is based on the recovery of residual biomass, such as forest residues that are currently left decaying on the ground.

Many studies have evaluated the role of bioenergy in climate change mitigation using modeling frameworks that simulate the dynamics of forest carbon stocks. However, these studies cannot assess the most cost-effective pathways to reducing GHG emissions. This study relies on the North American TIMES Energy Model (NATEM)—a bottom-up energy system model—to overcome the limitations of other approaches and take into account competition between market pathways. Such models are considered relevant instruments in generating different scenarios, preparing deep insights for choosing a cost-effective or favourable mix of technologies considering various assumptions and policy alternatives. This manuscript aims to critically analyze factors affecting GHG emissions associated with forest-based bioenergy technologies by introducing them in NATEM to investigate potential decarbonization pathways by 2050. This is the first time that different primary and secondary forest-based bioenergy technologies are being modeled in such a detailed bottom-up energy model like TIMES.

Fig. 1 presents the reference energy system of common and emerging conversion technologies to produce lignocellulosic-based bioenergy. It displays the flow of resource supply, production, and conversion applications to end-use technologies. The data for 45 primary and secondary technologies were acquired from various literature and modeled in NATEM after necessary modifications.

Instead of a simple category labeled “forest residues” as the only forest-based feedstock in NATEM, different residual forest-based biomass sources have been introduced along with new technologies that need specific feedstock types. For each of these feedstocks, a supply curve has been defined in the model with different availability potentials and their relative costs.

We considered four scenarios to explore the potential contribution of emerging forest-based bioenergy in Quebec’s energy transition: i) a business-as-usual (BAU) scenario without any additional GHG emission reduction constraints and without forest-based bioenergies; ii) a business-as-usual scenario in which the model can use forest-based bioenergies (BAU+BIOF) to explore the role of these bioenergies in Quebec’s energy system in the absence of additional GHG emission reduction constraints; and iii) two reduction scenarios with GHG emission reduction targets of 70% (GHGA) and 80% (GHGB) by 2050.

Decarbonizing Heavy Industry: The Most Challenging Task

In the BAU scenario, GHG emissions decrease between 2011 and 2025, before increasing between 2025 and 2050. The first decreasing trend is brought on by substituting some fossil fuel vehicles with electric vehicles due to governmental policies included in the scenario. But growing energy service demands cause GHG emissions to increase again afterwards (Fig. 2a).

Transportation is responsible for more than half of total GHG emissions in the different time periods and scenarios, except for GHGB in 2050 (Fig. 2b). Dependence on fossil fuels to satisfy transportation demands is the main reason for this sector’s emissions. In the GHGA scenario, significant reductions are achieved in the transportation, industrial, commercial, and residential sectors of 24.2, 6.7, 4.9, and 3.2 MtCO2-eq in 2050, respectively, compared to baseline values. In the GHGB scenario, further reductions are necessary in the transportation and industrial sectors to reach the more stringent target. The industrial sector is the main emitter by 2050 in GHGB, highlighting the challenge to decarbonize heavy industry.

Extensive Electrification: A Must

In 2011, the final energy consumption was dominated by oil products, electricity, and heat (Fig. 3a). Significant changes occur in GHG reduction scenarios by 2050. The percentage of electricity and heat are 60% and 70% of final energy consumption in the GHGA and GHGB scenarios, respectively, in 2050. This indicates that extensive electrification is required to reach the GHG reduction targets.

The Essential Contribution of Forest-Based Bioenergy

Bioenergy use increases over the time horizon in BAU and BAU+BIOF scenarios (Fig. 3b). This trend is boosted by strict GHG emission reduction constraints in GHGA and GHGB scenarios. The total amount of bioenergy in the GHGB scenario is lower than in the GHGA scenario, as priority is given to use limited feedstocks for some bioenergy such as cellulosic bioethanol instead of bio-based heat. The model gives preference to cellulosic bioethanol in the most stringent GHG scenario, cutting down on the need to reduce GHG emissions in the transportation sector. Bioenergy production becomes more diverse in the GHG reduction scenarios with the production of Fischer-Tropsch diesel and electricity as a co-product.

Conclusions

This study shows that transportation is the primary contributor to GHG emissions over the time horizon in all scenarios, except for GHGB in 2050. The industrial sector is the main emitter by 2050 in GHGB, indicating the difficulties to decarbonize heavy industry. Furthermore, extensive electrification is required to reach the GHG reduction targets. The bioenergy share is expected to increase considerably in the transportation and industrial sectors, cutting down on the need to reduce GHG emissions. Forest-based bioenergies such as cellulosic bioethanol, biobased heat, FT diesel, and electricity as a co-product can effectively support this energy transition.

The Quebec government envisions a 50% increase in bioenergy production by 2030 relative to the 2013 level. However, NATEM computes a bioenergy expansion of 75% for the GHGA and 114% for the GHGB scenarios in 2030 compared to the BAU scenario in 2013. Therefore, a greater penetration of bioenergy could be envisioned by the Quebec government in its 2030 plan for a green economy. This study reveals that forest-based bioenergy should be an important component of the decarbonization strategy of Quebec. Other world regions with a declining trend for traditional forest products should also consider such a strategy. Our future research addresses the limitations of this study, such as additional feedstock availability and treating biogenic CO₂ emissions as carbon neutral, which may bias the results.

Additional Information

Please see the following paper for further information:

Kouchaki-Penchah, H., Bahn, O., Vaillancourt, K. & Levasseur, A. The contribution of forest-based bioenergy in achieving deep decarbonization: Insights for Quebec (Canada) using a TIMES approach. Energy Conversion and Management 252, 115081 (2022).

Authors

Hamed Kouchaki Penchah is a PhD candidate in the Construction Engineering Department at École de technologie supérieure (ETS Montréal) with academic and professional experience in energy system modeling and sustainability evaluation of bioresource and bioenergy. His current research focuses on policy aspects of climate change and energy transition.

Annie Levasseur is a professor in the Construction Engineering Department at ÉTS. Her research focuses primarily on assessing the impacts of human activity on climate change and mitigation measures.