1 Greenhouse gas emissions of forest biomass supply chains to commercial scale liquid biofuel production plants Eero Jäppinen, Olli-Jussi Korpinen and Tapio Ranta Lappeenranta University of Technology Bioenergy research group Mikkeli, Finland
2 SCANDINAVIA Stockholm FINLAND Mikkeli Lappeenranta Helsinki St. Petersburg London Berlin RUSSIA
3 INTRODUCTION A commercial scale liquid biofuel plant may use 2 million m 3 (solid) of forest biomass Feedstock: harvesting residues, small diameter energy wood, stumps In this study these three feedstock categories have been estimated to amount to a total of 1 million m 3 (50% of total use) Energy content: 7.2 PJ/year à Supplied from domestic inland sources, in Finland Same type of feedstock is mainly used by power and heat sector.
4 STUMPS - spruce, from clearcuts ENERGY WOOD - from thinnings HARVESTING RESIDUES - branches, treetops - from clearcuts
5 How much is 1 million m 3 or 7.2 PJ? The largest plant using the same type of feedstock in the world is Alholmens Kraft (Finland) with approx. 2.2 PJ/year. à A commercial scale BtL-plant uses more than 3 times more. à 7.2 PJ ~ trucks ~ 2-3 trucks every hour year round. The techno-economical potential of forest biomass in Finland is ~ 115 PJ. Current use in Finland ~50 PJ. à 7.2 PJ would increase the demand by 14%. 1 million m 3 (solid) = 2.5 million m 3 (loose) One chip truck, full, 60 tons = 127 m 3 (loose)
6 Question nr 1: Does location matter?
7 Question nr 2: How much does it matter?
8 Case-studies Kemi Three possible locations for 2nd generation liquid biofuel production plants in Finland Rauma Porvoo
9 Some assumptions Availability = theoretical potential - 50% Not all forest owners are willing to sell these biomass fractions. Other limiting factors: competition, lack of subsidies, lack of information, forwarding distances etc. Current use is 44 % of theoretical potential, Therefore, -50% can be assumed to be a quite realistic scenario (In fact, also 100% availability scenario was calculated but it is not presented here) The shares of harvesting residues, stumps, and energy wood are equal to the proportions of these in the total potential within the supply area in question. Supply chains: Harvesting residues and energy wood: roadside chipping Stumps: crushing at railway loading locations or plant yard
10 METHODS Biomass availability : GIS analysis (Geographical Information System) spatial allocation of potential into 4 x 4 km grid according to productive forest land area forwarding distances truck transportation: takes into account distances travelled on different types of roads. GHG emissions: LCA (Life Cycle Assessment) whole production chain, including background processes manufacturing of machines and building of roads excluded 100 year time-horizon
11 RESULTS Supply areas logistical scenarios 100% by truck 67 % by truck 33 % by train 50% by truck 50% by train Railway loading places Not a likely scenario. 33 % by truck 67 % by train ForestBtL Oy (Kemi): A signiﬁcant propor]on of the feedstock is supplied by railway transporta]on
12 Feedstock proportions Kemi Rauma Porvoo
13 Supply chain GHG emissions? Harves]ng residues Energy wood Stumps Felling and bunching Stump li^ing Fer]liza]on? Soil carbon stock changes? Forwarding Comminu]on Transporta]on (truck and train) Storage?
14 Supply chain GHG emissions Transportation and comminution Base value: average electricity ; error bars: hydro- and coal power The more supplied by train, the better! GHG emissions ~ gco 2 eq/mj, if railway transportation is used Emissions are gco 2 eq/mj higher for Kemi in the north than for Porvoo or Rauma in the south.
15 RESULTS Basic scenario gco 2 eq/mj 3,50 3,00 2,50 2,00 Comminu]on and transporta]on Forwarding Northern Finland 1,50 1,00 0,50 Stump li^ing Southern Finland lat ~64 0,00 Southern Finland Northern Finland Felling and bunching Emissionscalculated according to the propor]ons of each frac]on in the total supply. Southern Finland: average of Porvoo and Rauma transporta]on and comminu]on emissions were the same for both loca]ons (33% by truck, 67% by train) feedstock propor]ons were almost equal Forwarding distances, average from center of stand to nearest roadside Northern Finland: 470 m, Southern Finland: 214 m
16 Supply chain GHG emissions? Harves]ng residues Energy wood Felling and bunching Stumps Stump li^ing only 24% of forest area is fer]lized, assuming 100 year rota]on if recommenda]ons for site selec]on are followed, fer]liza]on is not needed, in general fer]liza]on should be considered as way to increase forest produc]vity, rather than a way of offselng the nutrient loss due to collec]on biomass for energy use Fer]liza]on? Soil carbon stock changes? not currently accounted for in the EU sustainability criteria combus]on of biomass is assumed carbon neutral depends on type of biomass, par]cle size, condi]ons etc. depends on ]me- horizon! Forwarding Comminu]on Transporta]on (truck and train) Storage? a^er comminu]on (chipping, crushing) forest biomass feedstock will start decaying, and emilng CH 4 and N 2 O temperature, precipita]on, par]cle size, moisture content etc. data and published research on this issue is scarce if the comminuted feedstock is used without prolonged storage, emissions can be assumed to be low if stored for longer periods, the emissions may be very significant
17 RESULTS All inclusive gco 2 eq/mj 90, ,00 70,00 60, ,00 40, ,00 20,00 10, ,00 EU comparator value for fossil diesel - 35%, now - 60%, %, EU def.? Southern Finland? Northern Finland Error bars indicate rough range of possible emissions from storage of comminuted biomass for 6 months Soil carbon stock changes Fer]liza]on Comminu]on and transporta]on Forwarding Stump li^ing Felling and bunching Northern Finland Southern Finland lat ~64 Sources: Soil carbon stock changes: Repo et. al (2012). Storage emissions: Wihersaari (2005). Emissions due to soil carbon stock changes are higher in northern parts of the country, due to slower natural decay rates. If comminuted biomass is not stored for long periods, storage emissions can be assumed to be very low. Conversion efficiency from comminuted biomass to FT- diesel ~ 79-83% (literature value, not FT- plant consor]a es]ma]ons or pilots). Note: Emissions are calculated for a single event, they do not represent cumula]ve emissions over a 100 year ]me period.
18 DISCUSSION Some things to be considered Time horizon 100 years vs. for example 20 years soil carbon stock changes 2-5 times greater if time horizon is 20 years! (Source for decay rates: Repo et al. 2012) Largest relative difference is for harvesting residues in Southern Finland à C-debt discussion is on-going in the European Commission GWPs of CH 4 N 2 O 100 yr yr à possible storage emissions increase as well, if time horizon is shortened Feedstock availability Harvesting residues and stumps connected to industrial raw wood demand Small-diameter energy wood has the greatest potential How about other biomass feedstocks? On a global scale, sugar and starch crops and vegetable oil feedstocks account for more than 60%. EC default GHG values: sugar and starch crops: gco 2 eq/mj vegetable oils: gco 2 eq/mj These values do not include land use change or soil carbon. Finnish forest biomass is superior in GHG performance. Without soil carbon stock losses emissions are ~3 gco 2 eq/mj. But, biomasses with short rotation perform better if time horizon is shortened. Only one plant was granted EC (NER 300) funding in 2012 (Kemi).
19 CONCLUSIONS Question nr 1: Does location matter? Answer: Yes, it does. Question nr 2: How much does it matter? Answer: Not much, if soil carbon stock changes are omitted and time-horizon is 100 years. This is the perspective of the current EU sustainability criteria. If soil carbon stocks are taken into account, location matters a bit more. But the difference between locations is still only about 5 gco 2 eq/mj. Emissions (100 yr time horizon) still well below 60% GHG savings limit (2018 requirement) - But, if the time horizon is, for example, 20 years, things change.
20 Supply chain GHG emissions Some background data Soil carbon stock changes (decay rates by Repo et al have been used) Harvesting residues: 100 yr 20 yr Southern Finland: 5.9 gco 2 eq/mj 30.1 gco 2 eq/mj Northern Finland: 8.8 gco 2 eq/mj 30.2 gco 2 eq/mj Stumps: Southern Finland: 29.6 gco 2 eq/mj 68.6 gco 2 eq/mj Northern Finland: 35.4 gco 2 eq/mj 77.1 gco 2 eq/mj Energy wood: Southern Finland: 20.4 gco 2 eq/mj 47.9 gco 2 eq/mj Northern Finland: 24.8 gco 2 eq/mj 57.2 gco 2 eq/mj Emission calculations are based on 50% carbon content of wood and heating values of 7.49, 7.67 and 7.63 GJ/m 3 (solid), for harvesting residues, stumps and energy wood, respectively. Harves]ng residues Energy wood Felling and bunching Stumps Stump li^ing GHG emissions (gco 2 eq/mj) 100 years South North EW: ST: Fer]liza]on? Soil carbon stock changes? Forwarding Comminu]on Transporta]on (truck and train) HR: EW: ST: HR: EW: ST: Storage? up to 40 up to 40
21 Some key references Feedstock supply chains: Jäppinen E, Korpinen O- J, Ranta T. GHG Emissions of Forest- Biomass Supply Chains to Commercial- Scale Liquid- Biofuel Produc]on Plants in Finland (2013). GCB Bioenergy, published online 18 February 2013 Jäppinen E, Korpinen O- J, Lai]la J, Ranta T. Greenhouse Gas Emissions of Forest Bioenergy Supply and U]liza]on in Finland. Manuscript submiqed to Renewable & Sustainable Energy Reviews. Biomass poten]als: Anlla P, Korhonen KT, Asikainen A (2009). Forest energy poten]al of small trees from young stands in Finland. In: Savolainen, M. (Ed.), Bioenergy Finbio, Jyväskylä, Finland, pp Lai]la J, Asikainen A, Anlla P (2008). Energiapuuvarat. In: Energiapuun korjuun ympäristövaikutukset, tutkimusraporl, Kuusinen M, Ilvesniemi H, editors. Forestry Development Centre Tapio and Finnish Forest Research Ins]tute, Helsinki; 2008, Conversion efficiency: Oscar P.R. van Vliet O P R, Faaij A P C, Turkenburg W C. Fischer Tropsch diesel produc]on in a well- to- wheel perspec]ve: A carbon, energy flow and cost analysis, Energy Conversion and Management, Volume 50, Issue 4, April 2009, Pages Storage emissions: Wihersaari M. Evalua]on of greenhouse gas emission risks from storage of wood residue, Biomass and Bioenergy 2005, 5: Soil carbon stock changes: Repo A, Känkänen R, Tuovinen J- P, An]kainen R, Tuomi M., Vanhala P, Liski J. Forest bioenergy climate impact can be improved by alloca]ng forest residue removal. GCB Bioenergy 2012, 4: EU sustainability criteria and recommenda]ons: European commission. Direc]ve 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promo]on of the use of energy from renewable sources and amending and subsequently repealing Direc]ves 2001/77/EC and 2003/30/EC; European Commission. Report from the Commission to the Council and the European Parliament on Sustainability Requirements for the use of solid and gaseous biomass sources in electricity, hea]ng and cooling, European Commission, SEC (2010) 65, SEC (2010) 66; Global biomass use: IEA. World Energy Outlook 2012, Interna]onal Energy Agency, Paris.