Bioenergy and climate. Hillevi Eriksson, Swedish Forest Agency

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1 Bioenergy and climate Hillevi Eriksson, Swedish Forest Agency

2 Net effect on climate depends upon: GHG emissions at production and transportation CO 2, N 2 O, CH 4 Effects on carbon stocks in soils and biomass What pay-back time is acceptable?

3 Climate efficiancy of transport fuels Fossil fuels Biofuels 100 Average reduction of greenhouse gases when fossil vehicle fuels are replaced g carbon dioxide equivale ents per MJ fuel % Petrol Diesel Biodiesel - rape seed - 65 % Ethanol - wheat - 80 % Biogas - ley crops - 85 % Methanol - willow % Biogasliquid manure -100 Av: Pål Börjesson, Lunds universitet

4 How to limit systems? Biofuels By-products-process By-products-cultivation Energy input Credit of digestate G J p e r h e c ta re a n d y e a r Wheat-ethanol Wheat-biogas S.beet-ethanol S.beet-biogas Rape seed-rme Ley crops-biogas Maize-biogas Willow-ethanol Willow-FT-diesel Willow-DME/methanol Willow-methane (Cultivation in northern Europe on average arable land) Av: Pål Börjesson, Lunds universitet

5 The future = Optimized bio-refinery! Wood crops, straw, etc Residues Ley crops Annual crop etc Electricity Heat Electricity Liq. fuels Biogas Pellets Heat Products Av: Pål Börjesson, Lunds universitet

6 Suggestion Criteria on climate efficiency in prod/transp: Biofuels for transportation should have at the most 50 % of the emissions of petrol or diesel

7 Effects on carbon stock Ex forest is being converted to Salix: Minus 35 ton C in biomass and c. 10 ton C in soil = 45 ton C/ha Coal substitution: 3-6 ton C/ha/yr = 8-15 yrs payback time Ex roundwood for energy: - Coal substitution in 50 yrs: 80 ton C/ha - Carbon stock after 50 yrs: minus 20 ton C/ha

8 Suggestion Criteria for initial C stock losses: Land conversion should not result in losses larger than 30 % of substitution gain in 50 yrs time

9 Risk for N 2 O emissions following intensive fertilisation Substitution gain of 1 m 3 : 0.2 ton CO 2 -C Can be offset by 1,5 kg N released as N 2 O In Swedish forestry: 150 kg N typically gives +15 m3 (=>10 kg / m 3 ) Higher doses are being discussed What happens after harvest and in outflow areas?

10 Suggestion Criterion N fertilisation: Unless research show risks are minor - only compensatory doses of N should be applied

11 Biomass use in the Swedish forest sector ~7-8 % of biomass harvest: slash (and stumps) 42 % pulpwood 21 % energy from lignin, etc Annual stemwood harvest mill m 3 42 % saw logs 14% pulpchips 16 % sawn wood 33 % pulp & paper 12 % bark & sawdust & pieces 18 % direct harvest of fuelwood Source: Rolf Björheden, SkogForsk and Official Statistics of Sweden

12 Imported trspt fuels Sugar cane ethanol (certain C stock loss, high clim eff) =good Corn etanol (high fossil input energy = low clim eff, ineffective byproduct) = quite bad Biodiesel from palm oil plantations on drained/burned peatland (extremely high C stock loss, OK clim eff) = really bad

13 Energy mix in district heating E. Totalt tillförd energi för fjärrvärmeproduktion fördelad på olika energibärare heat pumps Spillvärme Värmepumpar TWh oil biomass Elenergi Oljeprodukter Biobränsle Kol och koks Naturgas och stadsgas 10 coal

14 Bioenergy development in Sweden The bioenergy share of the total energy use TWh : 9% 1980: 11% 1990: 15% 2000: 20% 2010: 30%

15 Demand for bioenergy further effects on C stock If large demands of wood: Improved afforestation/reforestation ambitions Improved forest legislation (SFA) Improved silviculture for high biomass production Biomass is harvested before natural disasters happens

16 Total tree volume development Dead/windthrown Broad-leaved Norway spruce Scots pine Year Million m m3

17 C stock = f(management system) i marken] [ton C/ha [Tid] mer N normalt bruk mindre N

18 Going back marken] 14 [ton C/ha i mer N upphör normalt bruk mindre N upphör [Tid]

19 Conclusions In 20 yrs we need to reach far in reducing fossil fuel consumption A too narrow time perspective for C stock losses - contraproductive for climate mitigation Suggestion: C stock loss < 30 % of 50 yrs substitution gain = OK With sound incentives (fossil fuel suppression), high fossil fuel use for prod/ transp will be too expensive