Task XV: Greenhouse Gas Balances of Bioenergy Systems
29 – 31 May 1996 – Radisson SAS Royal Park Hotel Stockholm, Sweden
Jointly organized by
| JOANNEUM RESEARCH Graz, Austria |
Swedish National Board for Industrial and Technical Development Stockholm, Sweden |
WEDNESDAY, 29 MAY 1996
(Heating plant fuelled with pulverized wood)
THURSDAY, 30 MAY 1996
Welcome and Introduction
Lars Tegner (NUTEK, Stockholm, Sweden)
Josef Spitzer (JOANNEUM RESEARCH, Graz, Austria)
Assessing the contribution of forest bioenergy to the carbon budget of Canada’s forests: a scaling problem
Mike Apps and Werner Kurz (Department of Natural Resources Canada, Canadian Forest Service, Edmonton, Canada; Essa Technologies Ltd., Vancouver, Canada
Effects of land-use competition and carbon-cycle feedbacks in projections of biomass energy
Haroon Kheshgi (Exxon Research and Engineering Company, Annandale NJ, USA)
Emissions of CO2 from integrated biomass energy systems – four case studies in the US
Ulf Boman (Vattenfall Utveckling AB, Vällingby, Sweden)
Using a large scale forestry scenario model for a European forests carbon balance
G.J. Nabuurs (Institute for Forestry and Nature Research, Wageningen, The Netherlands and European Forest Institute, Joensuu, Finland)
Forestry and biomass options in the economics of carbon dioxide mitigation
Folke Bohlin (Swedish University of Agricultural Sciences, Department of Forest-Industry-Market Studies, Uppsala, Sweden)
Contribution of forest sector on carbon sequestration in Finland
Ari Pussinen, Timo Karjalainen and Seppo Kellomaeki (University of Joensuu, Faculty of Forestry, Joensuu, Finland)
Carbon mitigation effects of forest bioenergy as a substitute for fossil energy
Bernhard Schlamadinger and Gregg Marland (JOANNEUM RESEARCH, Graz, Austria; Oak Ridge National Laboratory, Oak Ridge, TN, USA)
Carbon dioxide emissions from recovery and transportation of logging residues
Leif Gustavsson (Lund University, Department of Environmental and Energy Systems Studies, Sweden)
Role of bioenergy and forest products in limiting the carbon emissions of Finland
K. Pingoud (VTT-Energy, Espoo, Finland)
FRIDAY, 31 MAY 1996
Agreements to increase the role of the forest and bioenergy sectors for CO2 mitigation, and implications for the IPCC GHG inventory methodology
Hillevi Eriksson (Swedish University of Agricultural Sciences, Department of Forest Soils, Uppsala, Sweden)
Carbon flows and mitigation options in the forestry sector: Common methodology and results from eight developing countries
Willy Makundi and Jayant Sathaye (Lawrence Berkeley National Laboratory, Berkeley, CA, USA)
Scientific discussions
Topics that will be addressed (please add items that you consider important and bring them up at the workshop):
Task XV administrative matters
1. Workshop proceedings/publication
2. Bibliography
3. Activities 1996/97
4. Task XV www home page
5. Sabbaticals
6. Next workshop (date, location)
7. Other items
| Name | Institute | Address | Phone | Fax | |
|---|---|---|---|---|---|
| Apps Mike | Department of Natural Resources Canada, Canadian Forest Service |
5320 – 122 Street, Edmonton, Alberta, T6H 3S5 Canada |
+1 403 435 7305 | +1 403 435 7359 | mapps@nofc.forestry.ca |
| Bohlin Folke | SIMS Swedish University of Agricultural Sciences, Department of Forest- Industry-Market Studies |
Box 7054 S-750 07 Uppsala Sweden |
+46 18 673521 | +46 18 673522 | folke.bohlin@sims.slu.se |
| Boman Ulf | Vattenfall Utveckling AB |
162 87 Stockholm Sweden |
+46 8 739 6760 | +46 8 739 6802 | ulf.boman @utveckling.vattenfall.se |
| Bomgaard Lotte | COWI (Consulting Engineers and Planners AS) |
Parallelvej 15, DK-2800 Lyngby Denmark |
+45 45 97 20 62 | +45 45 97 22 12 | lbo@cowi.dk |
| Boström Bengt | NUTEK (Swedish National Board for Industrial and Technical Development) |
S-117 86 Stockholm Sweden |
+46 8 681 9388 | +46 8 681 9328 | bengt.bostrom@nutek.se |
| Ericson Sven-Olov | Vattenfall Utveckling AB |
162 87 Stockholm Sweden |
+46 8 739 6760 | +46 8 739 6802 | ulf.boman @utveckling.vattenfall.se |
| Eriksson Hillevi | Swedish University of Agricultural Sciences, Department of Forest Soils |
Box 7001 750 07 Uppsala Sweden |
+46 18 672233 | +46 18 673470 | hillevi.eriksson @sml.slu.se |
| Gustavsson Leif | Department of Environmental and Energy System Studies Lund University |
Gerdagatan 13 S-223 62 Lund Sweden |
+46 46 222 8641 | +46 46 222 8644 | leif.gustavsson @miljo.lth.se |
| Kheshgi Haroon | Exxon Research and Engineering Company |
Route 22E Annandale, NJ 08801 USA |
+908 730 2531 | +908 730 3301 | hskhesh@erenj.com |
| Lehtilä Antti | Technical Research Centre of Finland (VTT-Energy) |
P.O. Box 1606 FIN-02044 Espoo Finland |
+358 9 456 5074 | +358 9 456 6538 | kim.pingoud@vtt.fi |
| Makundi Willy R. | Lawrence Berkeley National Laboratory |
MS 90-4000 1 Cyclotron Road Berkeley CA 94720 USA |
+1 510 486 6852 | +1 510 486 6996 | wrmldc@dante.lbl.gov |
| Marland Gregg | Environmental Sciences Division, Oak Ridge National Laboratory |
Oak Ridge, Tennessee 37831-6335 USA |
+1 423 241 4850 | +1 423 574 2232 | gum@ornl.gov |
| Nabuurs Gert-Jan | European Forest Institute (EFI) | Torikatu 34 Fin 80100 Joensuu Finland |
+358 13 252020 | +358 13 124393 | nabuurs@efi.joensuu.fi |
| Olandersson Birgitta | NUTEK Swedish National Board for Industrial and Technical Development |
117 86 Stockholm Sweden |
+46 8 681 9364 | +46 8 681 9328 | birgitta.olandersson @nutek.se |
| Pingoud Kim | Technical Research Centre of Finland (VTT-Energy) |
P.O. Box 1606 FIN-02044 Espoo Finland |
+358 9 456 5074 | +358 9 456 6538 | kim.pingoud@vtt.fi |
| Pussinen Ari | Faculty of Forestry University of Joensuu |
P.O. Box 111 FIN-80101 Joensuu Finland |
+358 13 151 4446 | +358 13 151 4444 | pussinen @forest.joensuu.fi |
| Savolainen Ilkka | Technical Research Centre of Finland (VTT-Energy) |
P.O. Box 1606 FIN-02044 Espoo Finland |
+358 9 456 5062 | +358 9 456 6538 | ilkka.savolainen@vtt.fi |
| Schlamadinger Bernhard | JOANNEUM RESEARCH Institute of Energy Research |
Elisabethstr.11, A-8010 Graz Austria |
+43 316 876 1340 | +43 316 876 1320 | bernhard.schlamadinger @joanneum.at |
| Seppälä Heikki | Finnish Forest Research Institute |
Unioninkatu 40 A FIN-00170 Helsinki Finland |
+358 9 857 05717 | ||
| Spitzer Josef | JOANNEUM RESEARCH Institute of Energy Research |
Elisabethstr.11, A-8010 Graz Austria |
+43 316 876 1338 | +43 316 876 1320 | josef.spitzer @joanneum.at |
| Svensson Magdalena | NUTEK Swedish National Board for Industrial and Technical Development |
117 86 Stockholm Sweden |
+46 8 681 9364 | +46 8 681 9328 | birgitta.olandersson @nutek.se |
| Tegner Lars | NUTEK Swedish National Board for Industrial and Technical Development |
117 86 Stockholm |
+46 8 681 9384 | +46 8 681 9328 |
All papers below will be published in a Special Issue of Biomass and Bioenergy.
In this paper, which was prepared as part of IEA Bioenergy Task XV (“Greenhouse Gas Balances of Bioenergy Systems”), we outline a standard methodology for comparing the greenhouse gas balances of bioenergy systems with those of fossil energy systems. Emphasis is on a careful definition of system boundaries. The following issues are dealt with in detail: time interval analysed and changes of carbon stocks; reference energy systems; energy inputs required to produce, process and transport fuels; mass and energy losses along the entire fuel chain; energy embodied in facility infrastructure; distribution systems; cogeneration systems; by-products; waste wood and other biomass waste for energy; reference land use; and other environmental issues. For each of these areas recommendations are given on how analyses of greenhouse gas balances should be performed. In some cases we also point out alternative ways of doing the greenhouse gas accounting. Finally the paper gives some recommendations on how bioenergy systems should be optimized from a greenhouse-gas-emissions point of view.
Electric Power Research Institute (EPRI) and US Department of Energy (DOE) have been funding a number of case studies under the initiative entitled “Economic Development through Biomass Systems Integration”, with the objective to investigate the feasibility of integrated biomass energy systems, utilizing a dedicated feedstock supply system (DFSS) for energy production.
This paper deals with the full fuel cycle for four of these case studies, which have been examined with regards to the emissions of greenhouse gases, especially CO2.
Although the conversion of biomass to electricity in itself does not emit more CO2 than is captured by the biomass through photosynthesis, there will be some CO2-emissions from the DFSS. External energy is required for the production and transportation of the biomass feedstock, and this energy is mainly based on fossil fuels.
By using this input energy, CO2 and other greenhouse gases are emitted. But, by utilizing biomass with fossil fuels as external input fuels, we would get about 10-15 times more electric energy per unit fossil fuel, compared to a 100% coal power system.
By introducing a DFSS on former farmland, the amount of energy spent for production of crops can be reduced, the amount of fertilizers can be decreased, the soil can be improved, and a significant amount of energy will be produced, compared to an ordinary farm crop.
Compared to traditional coal based electricity production, the CO2-emissions are in most cases reduced significantly, as much as 95%.
The important conclusion is the great potential of reducing greenhouse gas emissions through the offset of coal by biomass.
The first part of this paper presents an overview of national forest carbon balance studies that have been carried out in Europe. Based on these national assessments, an estimate is made of the present role of European forests in the global carbon cycle. Differences in the methodologies applied are discussed.
At present, thirteen European countries have assessed a national forest and/or forest sector carbon balance. Together, these studies cover 96 million ha and present the average situation in the mid 1980s. Most of the studies have used a static methodology to convert forest inventory data into carbon. Extrapolating the studies to the total forest area of Europe (excl. FSU), yields a whole tree carbon sink of 92.5 Tg Cyr-1 (8.7% of the European emissions) and a whole tree carbon stock of 7428 Tg C. Although in general the applied methodologies are compareable, they differ considerably in the way net fluxes are assessed and in the apllied conversion coefficients. the role of forest fires in the European forest C balance might be larger than generally expected.
A disadvantage of the static methododlogies used is that they often regard only part of the carbon cycle which may result in misleading results concerning the role of the total forest sector; another disadvantage is that results are only valid for the year(s) on which the data are based.
The second part of the paper discusses a methodology whcih could be applied to every national forest and forest sector yielding more consistent results. The possibilities of using a large-scale forestry scenario model for a study on the present and future European forest sector carbon balance are presented.
Although Finland’s forest resources have been utilized intensively, the size of the total volume of the growing stock has increased since the mid-1960s, and hence increasing amounts of carbon have been sequestered by the forests. The net sequestration by forests has been substantial also when compared to the CO2 emissions resulting from energy generation and consumption based on fossil fuels and peat. It is also important from the point of view of mitigating the effects of climate change to assess how the sequestration capacity of the forests may change under changing climatic conditions.
This paper presents results of a study assessing the development of the forest and wood-product carbon budget for Finland based on regionally measured data, detailed dynamic models, and recent predictions concerning the changing climate.
The initial simulation situtation in 1990 was such that nearly 90% of the forest sector’s carbon storage was in the forests. Under current climatic conditions and management, the forest carbon storage increased 45% by 2100 and the wood-product storage by 320%. Under changing climate conditions, the forest carbon storage increased or decreased depending on the temperature changes. In Finland, the forest sector’s carbon storage was highest under modest climate warming 0.1°C per decade. The changes in carbon storages were different in southern and northern Finland.
Among the proposals for mitigating the increase of atmospheric CO2 are the possibility of reforesting degraded lands to sequester C or of using sustainable forest harvests to displace fossil fuels. Storing C on-site in forests and harvesting forests for a sustainable flow of forest products are not necessarily conflicting options if we recognize that their relative merits in mitigating net emissions of C will depend on site-specific factors like forest productivity and the efficiency with which harvested material is used. Since the land available for reforestation or development of forest plantations is limited, the relative merits of the different mitigation strategies need to be considered. We use a mathematical model of C stocks and flows to compare the net effect on C emissions to the atmosphere for the two approaches over a range of values of forest productivity and the efficiency of product use. When sustainably-produced forest products are used inefficiently to displace fossil fuels, the greater C benefit is achieved through reforestation and protection of standing forests, and increasing the rate of stand growth yields little gain. However, when forest products are used efficiently to displace fossil fuels, sustainable harvest produces the greater net C benefits, and the benefit increases rapidly with increasing productivity.
The Swedish biomass production potential could be significantly increased if new production methods, such as optimised fertilisation, were to be used. Optimised fertilisation on 25% of Swedish forest land could almost double the biomass potential from forestry, compared with no fertilisation, as both logging residues and large quantities of excess stem wood not needed for industrial purposes could be used for energy purposes. Together with energy crops and straw from agriculture, the total Swedish biomass potential would be about 230 TWh/yr, or half the current Swedish energy supply, if the demand for stem wood for building and industrial purposes were the same as today. Besides replacing fossil fuels and thus reducing current Swedish CO2 emissions by about 65%, this amount of biomass is enough to produce electricity equivalent to 20% of curent power production. A high intensity in biomass production would also reduce biomass transportation demands. There are, however, uncertainties regarding the future demand for stem wood for building and industrial purposes, the amount of arable land available for energy crop production, and future yields. Earlier estimates of the Swedish biomass potential vary from 15 to 125 TWh/yr. Biomass-based electricity is preferably produced through cogeneration using district heating systems in densely populated regions, and pulp industries in forest regions. Alcohols for transportation and stnad-alone power production are preferably produced in less densely populated regions with excess biomass.
The greenhouse impacts of the Finnish forest sector, including the forest biomass, forest industry, forest products in use, foreign trade and waste management, are discussed. The main carbon storages and flows are estimated and the greenhouse gas balance both totally and on national level are presented. The history of the greenhouse impact is also estimated and two future scenarios of the forest sector are compared. The present use and potential for additional use of bioenergy is also reviewed, and the impact of expanded bioenergy use on the national CO2 emissions is illustrated with scenario examples.
