Addendum to Avoided Greenhouse Gas Emissions From US Pulp and Paper Industry Biomass-Derived Electricity WP-24-05

EXECUTIVE SUMMARY

Although the US pulp and paper sector is the largest contributor to biomass-derived electricity in the US, primarily through energy efficient combined heat and power systems, all previous life cycle studies on the greenhouse gas (GHG) emission characteristics of biomass-derived energy have either focused upon the exclusive generation of electricity or have focused upon energy generation without allocating GHG benefits and burdens between steam and electricity. The US pulp and paper sector generates 95% of its on-site electricity needs via combined heat and power (CHP). CHP systems, sometimes referred to as cogeneration units, generate both steam and electricity; therefore, it is necessary to allocate the GHG emission impacts, as well as avoided emissions, from this sector via GHG allocation approaches. In this report, all major GHG allocation approaches are reviewed and applied to the US pulp and paper sector to generate allocation fractions for heat and electricity. Fenceline (only considering emissions generated or released by the facility) GHG emission intensities for the US pulp and paper sector, excluding consideration of avoided emissions, ranged from 82 to 316 g CO₂e/kWh, depending on the allocation approach used. In a series of studies on the GHG benefits of biomass energy consumption in the US forest products sector, National Council for Air and Stream Improvement, Inc. (NCASI) provided information on the avoided life cycle GHG emissions from biomass utilization for energy generation in the sector (NCASI 2011; Gaudreault et al. 2012; NCASI 2013 (revised 2014); NCASI 2017). Incorporating avoided emissions and considering GHG allocation approaches to allocate avoided emissions to steam and electricity generation, life cycle GHG emission intensities from industry-generated electricity range from (709) to (2814) g CO₂e/kWh for electricity derived from spent liquor solids and range from (482) to (1812) g CO₂e/kWh for electricity derived from all other biomass sources. The functions of the kraft recovery system that utilize black liquor, a by-product of the kraft pulping process, not only generate energy but recover pulping chemicals and manage black liquor solids and thus confer additional avoided GHG emissions when alternative use scenarios are considered compared to other biomass sources. Even when a portion of the on-site electricity generation at a pulp and paper mill is derived from supplemental fossil fuels, as is typical for the US pulp and paper sector, the large negative (i.e., avoided) emissions from utilizing biomass residuals more than offset the life cycle GHG emission amounts from the use of fossil fuels, resulting in negative emissions for industry-generated electricity.

NOTE: Since the appearance of our original white paper (NCASI. 2024. Avoided Greenhouse Gas Emissions from US Pulp and Paper Industry Biomass-Derived Electricity. White Paper (WP-24-05). Cary, NC: National Council for Air and Stream Improvement, Inc.), we have added additional text/perspective. We present the updated white paper with an additional appendix in this addendum.

DOWNLOAD WHITE PAPER

NCASI | WP-24-05 Addendum to Avoided Greenhouse Gas Emissions From US Pulp and Paper Industry Biomass-Derived Electricity

AUTHORED BY

Barry Malmberg, PhD, Principal Research Scientist

Keywords: Greenhouse Gas Emissions, Avoided Greenhouse Gas Emissions, Pulp and Paper, Electricity Generation, Biomass