Life cycle analysis for wood pellets

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Dennis Robertson
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1 Life cycle analysis for wood pellets W.E. Mabee Wood Pellet Workshop University of Bri4sh Columbia, Vancouver, CANADA 17 November 2014

2 From Sjolie, Solberg 2011 Source: Sjolie HK, Solberg B Environmental Science & Policy 14:

3 From Schakel et al Source: Schakel W et al ComparaIve life cycle assessment of biomass co- firing plants with carbon capture and storage. Applied Energy 131:

4 From Cespi et al Source: Cespi D. et al Int J Life Cycle Assess 19:89-99

5 From Pa et al Source: Pa et al Biomass and Bioenergy 49(2):

6 Main findings Common findings between LCA analyses suggest that wood pellet use in u4lity and residen4al applica4ons lead to overall reduc4ons in GHG emissions and overall environmental impacts Some interes4ng disconnects, which seem to be traced back to the way in which biomass is sourced and u4lized is biomass carbon neutral or not? There may be an issue with regards to 4me: how is 4me treated by the LCA analyses at hand?

8 The study region Study looked at biomass is supplied from standing trees and residues from 5.25 million hectares within the GLSL forest region Trees allocated for harvest that are not currently u4lized for tradi4onal products (avoid market impacts) Residues do not have a useful purpose in the region s conven4onal forest products industry and are ley to decompose in the forest

Forest carbon is modelled using a specialized model (FORCARB- ON) which quan4fies carbon stocks in living trees, soil, standing dead trees, down dead wood, forest floor,

12 Forest carbon is modelled using a specialized model (FORCARB- ON) which quan4fies carbon stocks in living trees, soil, standing dead trees, down dead wood, forest floor, and understory vegeta4on pools Inputs include harvest schedules and inventories Model es4mates forest carbon stocks over 100 years, a 4me frame relevant to the Ontario forest

14 Wood pellet life cycle inventory (spreadsheet- based) used in prior work Pellet produc4on from residues considered similar to that of pellets from standing trees 15% of input biomass is assumed to be consumed during pellet produc4on to dry the biomass Func4on unit is 1 kwh generated

15 BIOMASS Cellulose Pretreatment Lignin 6- C Sugar Hydrolysis Fermentation Hemicellulose 5,6- C Sugar Cracking Low- Grade Syngas, Heat Gasification Catalysis High- Grade Syngas BIOPRODUCTS BIOETHANOL BIOGASOLINE BTL BIOENERGY Cellulosic ethanol life cycle model is GHGenius Ethanol produc4on, transporta4on, distribu4on, and use as E85 fuel Reference gasoline case taken from the model Func4onal unit is 1 km driven

16 Without emissions associated with the forest, significant emission reduc4ons expected with pellets for electricity and cellulosic ethanol for transport Very small differences between residues and standing trees

17 Wood pellets from residues GHG emissions (MT CO 2 - equivalent) (posi9ve indicates atmospheric emission) Forest carbon Total emissions Bioenergy, excluding forest carbon Year

18 Cellulosic ethanol from residues GHG emissions (MT CO 2 - equivalent) (posi9ve indicates atmospheric emission) Forest carbon Total emissions Bioenergy, excluding forest carbon Year

19 Wood pellets from standing trees GHG emissions (MT CO 2 - equivalent) (posi9ve indicates atmospheric emission) Forest carbon Total emissions Bioenergy, excluding forest carbon Year

20 Cellulosic ethanol from standing trees GHG emissions (MT CO 2 - equivalent) (posi9ve indicates atmospheric emission) Forest carbon Total emissions Bioenergy, excluding forest carbon Year

21 Summary Wood residues: For pellets: Forest carbon impacts reduce total emission mi4ga4on (year 100) from 57 to 42 MtCO 2 - e For ethanol: Forest carbon impacts reduce total emission mi4ga4on (year 100) from 21 to 4.6 MtCO 2 - e Standing trees: For pellets: Forest carbon impacts reduce total emission mi4ga4on (year 100) from 267 to 117 MtCO 2 - e For ethanol: Forest carbon impacts turn GHG savings into net emissions (at least in the planning horizon)

22 BUT The pathway described is unlikely } Mature, standing trees are harvested only for bioethanol produc4on. A real business model would probably devote >50% of the fibre from any given tree to higher value products with long sequestra4on poten4als } The GLSL forest is a long- rota4on, semi- natural forest type. Short- rota4on forest planta4ons or a beher mix of end uses could easily 4p the analysis back to posi4ve Integrated LCA/forest carbon approach provides a beher understanding of GHG dynamics and could provide op4mal solu4ons to maximize emission reduc4ons

23 Follow- up studies Dwivedi et al Bioenergy Research 7(1): Examined the use of pulpwood (logs) as well as residues for bioenergy development Went a bit further than our study examined carbon sequestered in wood products, landfills Found that there is less carbon sequestered in products, landfills when wood diverted to energy, but not significant differences ayer 500 years

24 Takeaway Clearly the science supports the use of wood pellets Work might be done on energy use in pellet produc4on as this leads to significant impacts on overall LCA scores New LCA work has highlighted the need to consider 4me and impacts on other product groups Challenges remain: indirect land use change, appropriate 4me horizons for planning

25 Study team par4cularly Jon McKechnie (lead author) and collaborators/students/ PDFs from Queen s, Toronto, and UBC Members of IEA Bioenergy Task 39 Funding & research support from } NSERC } Natural Resources Canada } FPInnova4ons FERIC, Paprican Organizers and par4cipants at this mee4ng!

26 Team and partners DR Stewart Fast DR Saeed Ghafghazi DR Jamie Stephen DR Linghong Zhang Jean Blair PHD Sinead Earley PHD Joshua Goodfield BSC Megan MacCallum MA Lauren Malo MSC Nathan Manion PHD Peter Milley PHD Ricardo Smalling PHD Ashton Taylor MSC FFABnet Functionalized Fibre and Biochemicals Network

A changing role for Canadian biofuels

A changing role for Canadian biofuels Warren Mabee, Saeed Ghafghazi, Jean Blair 12 th Annual World Congress on Industrial Biotechnology Montreal, Canada 22 July 2015 Role inside NSERC Bioconversion Network