BIOENERGY (FROM NORWEGIAN FORESTS) GOOD OR BAD FOR THE CLIMATE?

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1 Presentation at NordGen Skog conference Odense, September 13-14, 2011 BIOENERGY (FROM NORWEGIAN FORESTS) GOOD OR BAD FOR THE CLIMATE? Per Kristian Rørstad Dept. of Ecology and Natural Resource Management Norwegian University of Life Sciences and Norwegian Centre for Bioenergy Research

2 OUTLINE Policy goals for renewable energy and bioenergy Forests current GHG contribution The Norwegian debate Forest bioenergy and climate effects Forest carbon dynamics GHG effects Albedo Conclusions

3 ENERGY POLICY GOALS IN NORWAY Climate neutrality by 2030 Forest biomass included Increased use of bioenergy: 14 TWh by 2020 ~ 7 mill m 3 roundwood If only from roundwood ~ 70% increase in harvest 13.2 TWh new renewable from green certificates by 2020 Probably only minor effects on bioenergy Norway s RED target = 67.5% renewables by 2020 Currently about 62% Domestic emissions are higher than the Kyoto target (2012)

4 PJ NORWEGIAN UNIVERSITY OF LIFE SCIENCES THE BIOENERGY POLICY GOAL Future Trend: 1,0166 year ,8 R² = 0,913 Historical Wood+waste 40 Distric heating Source: SSB

5 NORWEGIAN FORESTS IN THE GHG ACCOUNT Source: KLIF

6 mill m3 NORWEGIAN UNIVERSITY OF LIFE SCIENCES NORWEGIAN FORESTS HARVEST AND INCREMENT 15 Increment Harvest Source: SSB

7 THE DEBATE The debate in Norway has to large degree been a debate over GHG effects of increased harvest The Climate and Pollution Agency (KLIF) presented projections of effects of different measures in forestry (and other sectors): Klimakur (Climate Cure) One of these measures was to increase harvest from the current level of about 10 mill m 3 to 15 mill m 3 while assuming carbon neutrality The Norwegian Directorate for Nature Management has commented on the measures and is against most of them (on nature conservation grounds) No targets are set and no policy instruments in place for harvest or production levels

8 THE DEBATE

9 KEY ISSUES FROM THE DEBATE Increment is two to tree times the harvest Net accumulation of carbon in Norwegian forests equals roughly 50% of total emissions Does this mean that use of biomass from forest is climate neutral given the current harvest level? What if we increase the harvest level? How will harvest used for bioenergy affect GHG emissions and the climate?

10 CLIMATE/GHG IMPACTS OF BIOENERGY Bioenergy can not be said to be carbon neutral (without CCS) GHG effects depends mainly on: Carbon cycles in forests and how they are affected by harvest and other forest activities Substitution effects, i.e. reduction in the use of fossil fuels and other carbon intensive products (metals, concrete etc) Climate effects (radiative forcing): GHG effects Change in albedo Evapotranspiration, aerosols

11 FOREST CARBON CYCLE - HARVEST Harvest affects the forest carbon dynamics in various ways Removal of biomass (50 60% of tree biomass) Biomass is added to the forest floor/soil Changes soil conditions (exposure, moisture and mechanical disturbances) speeding up turnover This means that A large reduction in biomass (carbon) at the time of harvest Total biomass will decrease after harvest (for some time) Over the rotation, carbon levels will (normally) revert to pre-harvest levels

12 CARBON DYNAMICS Source: KLIF

13 FROM STAND TO NATIONAL SCALE Over a rotation period harvest may be said to be carbon neutral (given constant rotation length) Increased harvest means shorter rotation lengths At next harvest, carbon levels are lower than before the last harvest Average age decreases, indicating lower average carbon storage Increased harvest means lower forest carbon storage compared to a situation without an increase In Norway, carbon storage will increase in both cases, but less if harvest is increased

14 INCREASE IN CARBON STORAGE Source: KLIF

15 NET LOSS IN CARBON STORAGE Source: KLIF

16 SUBSTITUTION EFFECT BIOENERGY How the increased harvest (3-5 mill m 3 ) is used, is crucial for the climate gas effect First, will it lead to increased energy consumption or will it result in reduced use of fossil fuels? How the biomass is used (biodiesel, district heating, pellets, wood stoves, etc) and what it replaces (coal, oil, electricity) determines the substitution effect (avoided emission from fossil fuels) A simple measure for the substitution effect: the ratio between emissions from fossil fuels and bioenergy given the same energy consumption 50% means that bioenergy emits two times the emission from fossil fuel

17 SUBSTITUTION EFFECT EXAMPLES kg CO 2 /kwh utilized Substitution, ton CO 2 /m 3 Substitution effect Bioenergy - district heating 0.48 Ref. case El. Norwegian % El. Nordic mix % El. Euopean mix % El. coal % Oil - distric heating % Total effect = Effect on forest storage + Substitution effect

18 NET YEARLY EFFECT ON GHG CONCENTRATION Glulam beam in stead of steel beam, Electricity EU mix Measures evaluated in Klimakur Based on KLIF

19 CONCLUSIONS GHG EFFECTS Increased harvest will lead to increased concentration of greenhouse gases for a long time The duration and size of the negative effect (carbon dept) will depend on the substitution effects (bioenergy, sawn wood) The main reason is the decrease in forest carbon storage In the long run, the substitution effect will be larger than the storage effect Is the answer reduced harvest? Estimated effects on forest carbon storage from reducing harvest to zero Increased fossil emissions due to reduced use of wood = 0.36 ton CO 2 /m 3

20 GHG EFFECT OF A HARVEST BAN

21 CONCLUSIONS GHG EFFECTS - REVISED Increased harvest will have a negative GHG effect for more than 100 years, but will turn positive at some time Zero harvest will have a negative GHG effect after 100 years The main questions are who should solve the carbon problem and what is the right time frame? These are ethical questions Science/scientists cannot answer these questions What we as scientists definitely can do is to resolve some of the large uncertainties, for example: Carbon dynamics in old growth forest Mortality rates and risk of calamities

22 SHORT PAY-BACK TIME: HARVEST RESIDUES

23 CLIMATE EFFECTS ARE MORE THAN GHG GHG Albedo Source:Trenberth et al.

24 ALBEDO Average albedo (23 W/m 2 ) is small compared to total incoming radiation (6.7%), but large compared to net absorbed radiation (about 25 times larger) Rather large literature indicating that the albedo effect may offset the carbon effect from deforestation, or vice versa for afforestation Few relevant studies for Norwegian (or boreal) conditions One exception is Bright et al. (forthcoming): Increased harvest used for biofuel production The effect of changes in albedo (i.e. larger clear-cut area) is estimated in addition to the forest carbon storage and substitution effects

25 INCREASED HARVEST AND RADIATIVE FORCING Forest carbon Total Substitution Albedo Source: Bright et al.

26 CONCLUSIONS ALBEDO EFFECTS From a climate perspective, the albedo effect may imply: Shorter rotations (more open area), i.e. increased harvest No afforestation (along the western coast) Estimates are based on current climate, and the effect is mainly due to snow cover in February, March and April We need more research From a policy perspective, the albedo effect is not relevant Commitments are not based on forcing, but GHG emissions In a long(er) perspective, it may be relevant

27 GOOD OR BAD FOR THE CLIMATE? In the short/medium term bioenergy will lead to increased emissions of climate gases The albedo effect may offset the negative GHG effect It is unlikely that the bioenergy target (increase of 14 TWh by 2020) will be reached The resource base is not the challenge, but forest owners is Large uncertainties, esp. dynamics in old-growth forests In the (very) long term we know bioenergy is good for the climate With short term (2020) targets, the inter-generational challenges disappear