Appendix C Country Report Austria
Appendix C Country Report Austria Jonas Dahl and Ingwald Obernberger University of Technology Graz, Austria
The Market Implication of Integrated Management of Heavy Metals Flows for Bioenergy use in the European Union Thermie STR/1881/98-SE
Published 2002 by Kalmar University Department of Biology and Environmental Science Environmental Science Section SE-391 82 Kalmar, SWEDEN http://www.bom.hik.se/ess ISBN 91-89584-09-0 (This report, appendix C) ISBN 91-89584-06-6 (The main report)
This report is an appendix to the report “The Market Implication of Integrated Management for Heavy Metals Flows for Bioenergy use in the European Union”. The correct citation of this report is: Dahl, J. and Obernberger, I.: ’Country Report Austria’, p. 59. Appendix C in Johannesson, M. (ed.) et al.: 2002, The Market Implication of Integrated Management for Heavy Metals Flows for Bioenergy use in the European Union. Kalmar University, Department of Biology and Environmental Science, Kalmar, Sweden, p. 115.
2
Table of contents 1
Summary ...........................................................................................................................5
2
Introduction ......................................................................................................................7
3
Methodology......................................................................................................................9
4
General background data ..............................................................................................10 4.1 Geographical data, bedrock, climate and soil...........................................................10 4.2 Land use and population...........................................................................................10 4.3 Energy production and energy use ...........................................................................11 4.4 Use of Biomass energy .............................................................................................13 4.5 Energy policy and biomass potential in Austria.......................................................15 4.5.1 Energy Policy ...................................................................................................15 4.5.2 Potential biomass sources ................................................................................15 4.5.3 Potential usage of biomass ...............................................................................17
5
Present situation .............................................................................................................19 5.1 The flows of trace metals in Austria.........................................................................19 5.1 Em.............................................................................................................................21 5.2 issions and depositions of trace metals in Austria....................................................21 5.2.1 Emissions of Cd ................................................................................................21 5.2.2 Hg emissions.....................................................................................................22 5.2.3 Pb emissions .....................................................................................................22 5.2.4 Depositions of trace metals in Austria .............................................................23 5.3 Trace metals in soil...................................................................................................24 5.3.1 Concentrations of trace metals in arable soils.................................................24 5.3.2 Concentrations of trace metals in forest soils ..................................................25 5.4 Trace metals in mineral fertilisers, manure and sludge ............................................25 5.4.1 Mineral fertilizers .............................................................................................25 5.4.2 Manure..............................................................................................................26 5.4.3 Lime ..................................................................................................................26 5.4.4 Sewage sludge...................................................................................................26 5.4.5 Ash ....................................................................................................................27 5.5 Trace metals in food .................................................................................................27 5.6 Flows of heavy metals in arable land .......................................................................27 5.7 Flows of heavy metals in forest land ........................................................................28 5.8 Limiting values and guidelines.................................................................................29 5.8.1 Limiting emission values for combustion plants...............................................29 5.8.2 Trace metals in soil...........................................................................................29 5.8.3 The proper use of biomass ash on forest soil ...................................................30 5.8.4 The proper use of biomass ash on arable land.................................................31 5.8.5 Limiting values for sewage sludge....................................................................31 5.8.6 Limiting values for mineral fertilisers ..............................................................32 5.9 Costs and benefits.....................................................................................................32 5.9.1 Costs for disposal of ash...................................................................................32 5.9.2 Nutrient value of ash.........................................................................................32
3
5.9.3 5.9.4 5.9.5 6
Costs for preparing ash for ash utilisation.......................................................33 Costs for improved fractionation technology ...................................................33 Estimated value of Cadmium removed from arable soil ..................................34
Scenarios and case studies .............................................................................................35 6.1 6.2 6.3 6.4
Construction of scenarios .........................................................................................35 Bioenergy and biofuel scenarios...............................................................................35 Heavy metal flows in biomass combustion plants....................................................36 Results from scenarios calculated.............................................................................43
7
Summary and discussion of results...............................................................................49
8
Conclusions and recommendations...............................................................................54 8.1 8.2
9
Conclusions ..............................................................................................................54 Recommendations ....................................................................................................54
Literature ........................................................................................................................56
4
Summary This report discusses and describes the flow of trace metals in Austria today and for scenarios considered relevant for the future bioenergy system. Focus is on the trace metal cadmium (Cd), since this is a trace metal with high overall effect on human health and high biotoxicity. It is also readily available for uptake in plants and is therefore of great importance when considering the different aspects of a biomass energy system. Due to the Austrian legislations, Cadmiumverordnung (BGBI. Nr. 855/1993), the use of cadmium in pigment and PVC products are banned in Austria since in 1993 and the input of cadmium to the Austrian society are decreasing. The current main flow of Cd is the usage of Ni-Cd batteries. This flow is however, believed to decline as well, due to the introduction of more environmentally friendly alternative batteries. During combustion Cd (and Pb) are concentrated in the fly ash and flue dust particles and thus, if not precipitated in filters, emitted to the air. Small scale and medium scale biomass combustion units with less or no flue dust precipitation have thus been concluded to be the major contributors to the emissions of Cd in Austria. Large-scale units are required to be equipped with efficient fly ash precipitation units and the emissions of particles and trace elements from such plants are thus much lower. Furthermore, not only the emissions of trace elements are lower in large scale biomass plants compared to small and medium scale, but also a better management of trace metals can be achieved by implementing new developed combustion and trace metal fractionation technologies. By using the new combustion technologies toxic and volatile trace elements such as Pb and Cd are concentrated into a small ash fraction, while the main ash fraction is poor in these elements and can thus be utilised as a valuable fertilising material. The ash fraction with high concentrations of these trace elements is send for safe disposal and represents thus a separation of these elements from the environment. Austria is the most densely wooded land in Europe and consequently heating with wood is an important energy source, especially for residential heating in rural areas. The current annual utilisation of biomass for energy production in Austria is about 120 PJ primary energy /year and the potential is estimated to an additional 100 PJ primary energy /year. Due to the relatively high amount of Cd in Biomass compared to many fossil fuels, the predicted increase of biomass combustion is of great relevance for future Cd emissions. The case studies in this report revealed that depending on the future combustion technology used, biomass combustion could either be used as a process for separating Cd and Pb from the environment (best case) or a potential risk of becoming the single major domestic emitter of these elements instead (worst case). Thus, in order to avoid a worst case scenario , development of modern small scale stoves with efficient particle separation filters is necessary, or a change to district heating where the biomass is combusted in large to medium scale plants with efficient dust particle filters and implemented fractionation technologies instead. Although the current levels of heavy metals in Austrian arable soil are not considered to be exceptionally high, previous and current use of fertilisers and lime on arable land cause cadmium to accumulate in Austrian arable soil. However, results from scenario calculations revealed that by cultivating willow (Salix sp) on about 10 % of the total arable land in Austria (1 500 km2) the removal of cadmium due to uptake in willow crop would alone (3 825 kg/year) exceed the total influx of Cd to arable soil today (2 347 kg/year) and a net reduction of Cd from arable soil would be obtained. The general flows of cadmium in Austria forest soil were concluded difficult to calculate, due to large deviations between different locations. While the calculations performed in this study indicate a general net loss of Cd from forest soil (about 1 330 kg/ year), mainly due to 5
leakage, several other studies indicate local accumulation of Cd in forest topsoils, especially in high altitude alpine forest regions where the depositions are significantly higher than in lower regions. Another reason for this discrepancy is large deviations in soil composition which influence the mobility of Cd in the soil and thus the leakage factor. In areas with high accumulations an increased outake and utilisation of biomass is thus the best way of decreasing Cd from such regions. Cost–benefit calculations indicate a need for the development of new more cost effective and efficient filters for medium scale to small scale biomass combustion units. The current implementation of filters to such units is to expensive compared to the benefits estimated with current data.
6
2 Introduction The main purpose of this study is to illustrate the cadmium flow in Austria as a result of changed use of biofuels and to discuss associated environmental and health risks and possibilities. The report describes the flows of cadmium in Austria 1995 and scenarios considered relevant for the future bioenergy system. Domestic emissions of other environmentally relevant trace metals such as mercury (Hg) and lead (Pb) are also discussed, but the main focus is on cadmium (Cd). The Austrian study constitutes a part of the EU-financed research project STR-1881-98. The overall objective of the EU project is to make an assessment of the market implications of integrated heavy metals management for bioenergy use in the European Union. This is achieved by performing case studies of a selected number of countries (Sweden, Denmark, Austria, United Kingdom and France) showing the present situation of bioenergy use and trace metals flows. In addition, scenarios for the future, showing how the metal flows may change as a result from increased use of bioenergy, are constructed. Possibilities and risks to utilise bioenergy for cleaning of arable land is addressed. and in some cases even cleaning of contaminated industrial land is discussed (Riddel-Black et al., 1997). Based on the individual country reports and some key data from other EU-countries, it is the aim of the project to extrapolate the results achieved to the whole European Union. The amounts of heavy metals in Austrian soils are increasing. In forest this is mainly due to dry and wet deposition from air borne contaminants (Weiss, 1996; Zechmeister, 1995) while arable soils also experience high influxes by the use of fertilizers (BFL, 1997). The trace metal flows in the arable land and forest ecosystems are connected to the bioenergy production system by the plant uptake of trace metals, the use of biomass as fuel, and by recycling of ash. In addition to the efforts to reduce the input of trace metal to the soil, the outtake of biomass, for energy purposes, provides a way of removing trace metals from the ecosystem in areas were concentrations are considered to be to high (Narodoslawsky et al., 1996). In the first progress report of the project (Johanneson, 2000), cadmium was characterised as a metal of high risk and high biofuel relevance, due to its relatively high toxicity and the high plant availability. Lead and mercury are defined as metals with high general risk and moderate biofuel relevance (less plant available). Zinc is a metal with moderate general risk and high biofuel relevance, while arsenic in general constitutes a moderate risk and moderate biofuel relevance. The uptake and removal of cadmium from soil by the use of energy crops have been discussed and considered as a method for cleaning of arable soils. Willow (from the Willow (Salix sp) family) has a greater potential for accumulating cadmium than cereals, which make it interesting for this purpose (Riddel-Black et al., 1997). However, if the ash from the energy conversion process is to be brought back as a fertiliser, the metal content needs to be low. Separation of metals from the ash can take place either during the combustion by special design of the boiler (Dahl et al, 2001)or in a post-combustion ash-treatment process. In the case study of Austria, there has been emphasis on making an assessment how the objectives in the biomass utilisation could be a possibility to clean the arable soils but also to decrease emissions to air from biomass combustion. Furthermore, a technical database containing data on fractionation of trace elements in different biomass combustion units was compiled by TUG. This database was provided to the other partners as a basis for the case studies performed.
7
The disposition of the report is as follows: In chapter 1 are the main results summarised. Chapter 2 (this chapter), presents the aims of this study and puts the study it in perspective to other studies within this area of research. Chapter 3 describes the multi scenario systems analysis approach used in the project. Chapter 4, gives some important background data of Austria, such as climate, land use, energy use and biomass potential. Chapter 5 describes the situation in Austria 1992-98 concerning the flows of some trace metals with focus on the heavy metal cadmium. The flows of cadmium in the society are described as well as the flows in the soil/biofuel/combustion system. Limit values, guideline values, targets and national goals etc are as well as some crucial costs figures concerning the biofuel combustion system also presented in chapter 5. Chapter 6 describes three scenarios for the future soil/biofuel/combustion system: A best case scenario, a worst case scenario and a most probable case scenario are constructed for 2010 and 2030. The main data elaborated in the scenarios are the future use of energy, biofuels and combustion/cleaning techniques. Results from the different case studies are compiled in figures that show the cadmium flows in soil/biofuel/combustion system. Chapter 7 discuss the risks and possibilities of changes in flow of cadmium in the soil/biofuel/combustion system as a result of different use of biofuels and cleaning techniques. Chapter 8 presents the main conclusions from the study and gives some recommendation for policymakers and others that have an influence on the future use of biofuels in Austria. In chapter 9 are the references listed.
8
3 Methodology The flows of heavy metals, and cadmium especially, are described at three levels First level shows the overall flow, i.e. all flows and storage (emission, deposition, import and export of products). This level makes it possible to compare the overall flows of metals with the flow in the bioenergy system today and in the scenarios. Second level is the flow and storage of trace metals in the agricultural and forestry system. Third level is the flow of trace metals in the biofuel energy system. The following four types of case studies are constructed: State of the art – a description of the situation in the country in 1995. The year 1995 was chosen to make sure that data are available and possible to compare. However, sometime it is was still difficult to find relevant data for 1995 and in these cases data from a year as close to 1995 as possible to was used instead. The most probable case relevant to bioenergy use in Austria 2010 and 2030– the development that is judged to be the most probable one. The best case relevant to bioenergy use in 2010 and 2030 in Austria – the combination of data that will result in the best outcome and give the overall biggest benefit. The worst case relevant to bioenergy use in 2010 and 2030 in Austria – the combination of data that constitute the most severe risk. The basic data that is collected for the studies should be used in: Mapping the bioenergy situation in 1995. Construction of different bioenergy scenarios covering the energy amount for the near future, year 2010, and on long term, year 2030. Construction of different biofuel scenarios for the years 2010 and 2030. Construction of different scenarios for biomass use and combustion technologies.
9
4 General background data 4.1 Geographical data, bedrock, climate and soil The Republic of Austria, situated in the heart of Central Europe, covers an area of 83 858 km². Three fourths of Austria is occupied by the alps which traverse from west to east of the country. The mountains are mainly in the west of Austria while the eastern and northern margins are flatter or gently sloping. The highest peak in Austria is the Grossglockner (3,798 m) in the west of Austria and the lowest point is Lake Neusiedl (115 m) on the eastern border to Hungary. (CIA, 2001) The bedrock in the northeast of Austria is dominated by the Bohemian granite mass while the northwest of Austria is dominated by lime rich soil.The Austrian Alps may be subdivided into a northern and a southern limestone range, each of which is composed of mountains. These two ranges are separated by a central range that is composed of crystalline rocks. North of this massive mountain range, which forms the physical backbone of the country, lies a hilly subalpine region, stretching between the northern Alps and the Danube, while to the north of that river lies a richly wooded foothill area. The lowland area east of Vienna may be regarded as a western extension of the great Hungarian Plain (Encyclopædia Britannica Online. 2001) The climate is continental temperate, with cold winters and frequent rain in lowlands and snow in the mountains. The summers are cool with occasional showers. The wooded slopes of the Alps and the small portion of the plains of southeastern Europe are characterized by differing climatic zones. In the lowlands and the hilly eastern regions, the median temperature ranges from -0.9 °C in January to 20.3 °C in July. In those regions above 3 000 m , by contrast, the temperature range is between -11.3 °C, with a snow cover of about 3 m in January, and 2.1 °C in July, with about 1.5 m of snow cover. The prevailing wind is from the west, and the wetter regions of Austria are thus in the west and have an Atlantic climate with a yearly rainfall of about 1 000 mm; the eastern regions, in particular those under the influence of the drier, more continental type of climate, have less precipitation. (Encyclopædia Britannica Online. 2001) “The soils in Austria are approximately 6 000 years old, which means that particular consideration must be given to soil conservation. Conditioned by Austria's extremely diverse lithological structure, the sharp changes in relief and the varying climate, the soils also change over very short distances. Broadly speaking, in the Waldviertel and Mühlviertel areas there are predominantly silicate brown soils, brown podzolic soils and podzols, in the Northern Alpine foothills para-brown soils, gleysolic para-brown soils and Pseudogley soils and in the Southeastern Alpine foothills Pseudogley soils. High quality chernozems (steppeland black earths) occur in the Vienna Basin, in particular north of the Danube; in the southern part, chernozems and rendzinas on gravel predominate. Rendzinas also cover large areas of the Northern and Southern Limestone Alps, whereas podzolic and semipodzols covers much of the Central Alps. In the wide valleys there are extensive floodplain forest soils. In the Seewinkel area, one of the lowest areas in Austria, there are saline soils.” (Encyclopedia of Austria, 2001)
4.2 Land use and population. In 1995, Austria had a total population of about 8 047 000, and an population density of about 100 inhabitants per square kilometre (Statistic Austria, 2001). Austria is the most densely wooded land in Europe and forest make up about 42 % of Austria’s total area (Table 4.2a). The most common trees are conifer trees (69%), mainly spruce (56%) (Hauk, 1997). In Table 4.2a the use of land in Austria and in Table 4.2b, the production on arable land are displayed for year 1997. The data are displayed for 1997 as no such detailed data was found for the
10
reference year 1995. The dislocation of land use is however a slow process and the data from 1997 are consequently assumed to be relevant for 1995 as well. Table 4.2a: Land use (1997)
2
km 131974 91383 101051 816 341969 11426 81637 21300 21302 831858
Arable land Intensive grass land Extensive grass land (alpine pasture, etc. ) Other agricultural land (wine, fruit etc.) Forest Lakes and streams Alpine mountain Residental area Other (roads, etc.) Total area Source: (Wirtschaftkammer, 2001; BMFL, 1999)
Table 4.2.b: Arable land use (1997)
2
% 17 11 12 1 42 2 10 3 3 100
Crop Cereals Leguminous vegetables Root crops
km 81552 545 755
% 61.2 3.9 5.4
Industrial crops Fodder crops Fallow lands/ set aside Other arable crops Total Source: (EUROSTAT, 2000)
11132 21124 741 126 131974
8.1 15.2 5.3 0.9 100
4.3 Energy production and energy use The main part of the Austrian energy supply originates from fossil fuels and as Austria has no significant fossil fuel resources, about 2/3 (64.4 % in 1995) of the primary energy sources are imported (Table 4.3). Biomass and hydroelectricity are the dominating domestic energy carries as Austria does not use nuclear energy (Table 4.3a). According to the Austrian official statistic institute, (Statistic Austria, 1998), the contribution of biomass energy was, 1993, about 13.5 % of the total final energy use in Austria. This equalled about 117.5 PJ. However, (Obernberger, 1997) showed that this value was overestimated with about 1.8 % due to usage of incorrect density values for the biomass. The main part of the biomass utilised in Austria is softwood while statistic Austria calculates all biomass conversion with the density of hard wood. This error has not changed since 1993 and thus the amount of energy from biomass is typically overestimated in the literature based on these values. Furthermore, another difference between Statistik Austria and Obernberger is that Statistic Austria includes organic waste as biomass energy while this is excluded from the calculations of Obernberger. In this work mainly the results of Obernberger are used for case studies, although values of Statitik Austria is the more frequently used values in other investigations. Due to this, both figures based on Statistic Austria and the figures for 1995 corrected according to (Obernberger, 1999) are listed in Table 4.3a to Table 4.3d.
11
Table 4.3a: Annual primary energy supply by energy carrier (1995) PJ % 2 1 11 143 (120) Biomass 138 11 Coal 173 13 Hydro power 282 22 Natural gas 0 0 Nuclear power 523 41 Oil 26 2 Electricity 11285 100 Total Source: (E.V.A., 1998), 1: includes organic waste, 2: with corrections according to (Obernberger, 1997; 1999)
Table 4.3b: Domestic annual primary energy supply by energy carrier (1995) 1
Biomass Coal Hydro power Natural gas Nuclear power Oil Total
PJ 141 (117) 14 173 53 0 46 427
2
% 33 3 41 12 0 11 100
Source: (E.V.A., 1998), 1: includes organic waste, 2: corrections according to (Obernberger, 1997; 1999)
Table 4.3c: Annual final energy use in Austria by energy source (1995) PJ % 58 6 Coal 371 41 Oil 156 17 Gas 124 (110)2 14 Biomass 31 3 District heating 170 19 Electric energy 910 100 Total Source: (Austrian Biomass Association, 2000), 2: with corrections according to (Obernberger, 1997; 1999)
Table 4.3d: Annual final energy consumption by application (1995) PJ 351 Space heating and hot water 195 Process heat 87 Mechanical work 250 Mobility 27 Lighting and Electric devices (e.g. computers) 910 Total Source: (Austrian Biomass Association, 2000)
% 39 21 10 27 3 100
12
4.4 Use of Biomass energy With forest making up about 42 % of the landscape, Austria is among the most densely wooded countries in Europe, and wood or by-products from wood industry (such as bark and saw dust) makes up the main part of the biomass used for energy production. The current forest stock is estimated to 988 million m3 with a growth of about 27 million m3 annually. 20 million m3 of this is annually harvested and about 3.6 million m3 (23 %) are used as firewood. Other sources of biomass are black liqueur recovery combustion in the pulp and paper industry, bio-diesel produced from oilseeds as well as gas from landfills or biogas production. A small amount of biomass energy is also produced from combustion of straw. Table 4.4a shows the detailed distribution of primary and used biomass energy for 1993. No such detailed data was available for the year 1995 and thus the data of 1993 are used as a basis for the further case studies. Table 4.4a: Annual primary and finally used energy from biomass (1993) Primary energy PJ
Used energy (heat+el)
%
PJ
%
47.5
57
47.0
59
Bark
9.5
11
7.6
10
Straw
0.9
1
0.9
1
Fire wood
7.9
10
7.9
10
wood residues from forestry and industry
17.1
21
16.5
21
Total solid biomass Black liquor combustion in the paper and paper industry
82.9 18
100
79.8 15.3
100
Bio-diesel Landfill-, Sewage- and Bio-gas Total biomass
0.5 1.4 102.8
Waste wood
0.3 0.3
Source: (Obernberger I, 1997), combustible waste is not included
Table 4.4b: Annual primary energy from solid biomass utilisation by application (1993) Primary energy PJ Residential space heating by single or central heating boilers Industrial use District heating Total
%
Average energy efficiency %
Average full load hours hours/ year
59.6
72
65
1 600
21.0 2.3 82.9
25 3 100
80 80
6 500 1 650
Source: (Obernberger, 1997)
The major part (72 %) of the solid biomass is utilised in small scale residential single furnaces (tiled stoves, log stoves etc.) or central heating boilers (Table 4.4b) and mainly in rural areas where local supply of wood is utilized. In urban areas old wood fired heating systems are and have largely been replaced with systems based on fossil fuels (natural gas and oil) or district heating. This trend is continuing and the percentage of households using residential furnaces with firewood for their heating systems is decreasing (Table 4.4c).
13
Table 4.4c: Heating of households by energy carrier 1990 n
1995 %
n
1999 %
n
%
Wood
608
21%
572
18%
521
16%
Coal/coke
405
14%
215
7%
120
4%
Oil
781
27%
843
27%
925
29%
Natural gas
579
20%
777
25%
882
27%
Electricity
260
9%
312
10%
286
9%
District heating
231
8%
347
11%
444
14%
29
1%
56
2%
45
1%
100% 31123
100%
31223
100%
Others
21893
Total
n: number of thousands of households Source: (Austrian Biomass Association, 2000, Wirtschaftkammer Österreich, 2001)
The major reasons for this declining trend, is the comfort of gas- and oil- fired heating systems or district heating compared to old fashioned wood log fired systems. The declining trend in biomass usage for household heating is however partly damped by the fact that the heat from biomass in district heating system is increasing, but also by an expanding market of small scale automatically feed central heating wood boilers. Especially systems using wood pellets (Jonas et al., 2001) are showing a positive and growing trend since 1997 (Table 4.4d ) Table 4.4d: Annually installed number and total capacity of biomass boilers with automatic fuel feeding systems in Austria 19851992
199 3
10 234
199 4
199 5
199 6
199 7
199 8
199 9
2000
Sum numbers
Total capacity (MW)
1 443 1 479 1 579 2 280 2 027 1 913 2 058
2 149
23 859
425 1 323 2 128
3 466
7 342
1 175
Small scale
(£ 100 kW)
- wood chips/ wood log - pellets Medium scale
(100 to 1 MW)
1 272
134
151
172
214
256
280
159
223
2 701
778
154
15
20
23
34
45
50
42
27
391
888
1 592 1 650 1 774 2 528 3 178 4 889 6 515
9 331
41 635
2 841
Large scale
(> 1MW) Sum
11 660
Source: (Jonas et al., 2001)
Biomass-fired district heating networks in Austria have been developed and built in rural areas since the mid-eighties and this market has meanwhile seen a considerable and constant upturn. Approximately 6.2 PJ of district heat from 501 biomass combustion plants was in the beginning of year 2000 produced in Austria (Austrian Biomass Association, 2000) in comparison to about 2.3 PJ of district heat from 163 biomass combustion plants in the year 1993 (Table 4.4d). The main part of these plants are using wood based biomass fuels but in the reference year 1995, also 10 district heating plants combusting straw and energy crops were operative with a cumulated capacity of 20.4 MW.
14
4.5 Energy policy and biomass potential in Austria 4.5.1 Energy Policy Austria's energy policy, based on the principles of the IEA/OECD, is laid down in the Energy Reports of the Austrian Government (IEA, 1998; Rijpkema et al, 1997) Austria's energy policy objectives, reaffirmed in the 1993 and 1996 Energy report, include security of supply by reducing import dependency of fossil fuels, increase environmental compatibility and social acceptability. Priority is given to energy conservation, to increased use of renewable energy sources, and to a shift of emphasis from government interventions to market forces. Austria is very much in favour of energy from biomass. Despite the fact that energy from biomass is already an important energy source, the Austrian government has enacted a development plan for energy from biomass for the period 1995 – 2015, increasing the amount of biomass energy to 140 PJ per year. Increased renewable energy use is encouraged at both the national and provincial levels. Both the federal and provincial governments have responsibilities for aspects of energy policy. Both can enact energy legislation, and both are implementing measures to promote renewables. The main forms of support are capital investment subsidies, R&D measures, and support for renewable electricity production via favourable buy- back tariffs. The Government considers that waste still has considerable unexploited potential. Official energy research policy therefore stresses the need to concentrate efforts in this area. Besides long-term experiments involving energy cropping (cultivating and harvesting fast-growing plants) and the production of biogenic fuels, there have been projects to improve wood-fired systems, especially on a small scale. Austrian Government policy on renewables points out the macroeconomic advantages of biomass use, such as new possibilities in rural areas, and includes several schemes to promote small boilers and district heating systems. A series of measures were agreed by the Government to promote the use of biomass energy. They include: · · · · · ·
use of wood waste; promotion of energy cropping; increased use of biomass in district heating; promotion of biomass for process heat and in combined heat and power; promotion of biofuels; use of ethanol as a fuel component.
In view of the declining profit margin for traditional agricultural products, biomass also gains importance for farmers as an alternative source of income. Research projects on energy cropping are co-sponsored by the Federal Government and the provinces.
4.5.2 Potential biomass sources The potential biomass energy development has been estimated by several authers before (Rathbauer et al., 1999, Lechner et al., 1998), but show all different results according to the conditions they were based on. It is however not the aim of this project to compare and discuss all these estimations and thus it was decided to mainly use the potentials calculated by Obernberger (Obernberger, 1997). One of the reason for choosing this estimation was that most other predictions are based on the data from Statistic Austria (see previous discussion). Due to the large amount of forest in Austria, it is natural that the main biomass potential comes from increased forestry activities. At the moments only 63 % of the annual forest growth is harvested. The reason is partly due to topographic constrains but also due to
15
unfavourable economic conditions for a full utilisation. According to (Obernberger, 1997) the amount of biomass from forest could in short term easily be increased with 7 PJ per year by an increased usage of forest residues from large scale forestry (Table 4.5a). Another short term potential is a increased usage of straw reserves from the agricultural sector. This potential is estimated to be about 4 PJ per year. Table 4.5a: Short term biomass potential in Austria PJ per year 7
Firewood/ Forest residues from clean cuts
% 64
4 11
Straw Sum Source: (Obernberger, 1997)
36 100
The mean to long term biomass potential for energy production is estimated to be 100 PJ per year (Table 4.5b ). This potential comprises not only the short term potential use of forest residues but also a total increased harvest of forest, resulting in increased residual products from saw mills (saw dust, bark , etc.) as well as more forest residues from clean cuts. The total potential from an increased forest usage is estimated to be about 49 PJ per year. The use of short rotation crops on arable land is currently small in Austria. In 1995 it existed about 783 ha test fields with different kinds of test plants, although about 150,000 ha are estimated to be available comprising a potential energy of 30.9 PJ per year (based on a mixture of energy crops and short rotation forest with an average yield of 12 ton d.b./ha year). However, cheap fossil energy currently makes such short rotation cultivation non economical. The usage of straw is estimated to have a total mean to long term potential of 31 PJ per year. The calculations are in this case based on a return to old wheat sorts with longer stem increasing the combustible part of the straw. A survey among the farmers showed no hinder for such change provided there is a secure market for the straw (Obernberger, 1997). Table 4.5b: Mean to long term biomass potential in Austria PJ per year 7
Firewood / forest residues from clean cuts
49 13 31 100
Increased forest usage Straw Energy crops and short rotation forest Sum Source : (Obernberger, 1997)
16
% 7 49 13 31 100
4.5.3 Potential usage of biomass Based on biomass energy balances from 1993 and the average annually installed capacity between 1991 and 1995 Obernberger (1997) estimated the following yearly development for the future biomass utilisation (table 4.5c). Table 4.5c: Capacity potential for biomass combustion boilers in Austria (based on the development between 1991 to 1996)
Increase in capacity Water content Full load
[MW/year]
Efficiency
[%]
[wt %] [h/year]
Increased primary [PJ/year] energy Source: (Obernberger, 1997)
Bark and wood chip furnaces >1MW 0.11MW
55
28
37
34
53
19
35
44
43
46
101
112
116
105
91
Medium scale 0.1-1.0 MW
53
63
35
29
46
39
40
36
37
53
54
75
96
54
68
Small scale (wood chips)
The Market Implication of Integrated Management of Heavy Metals Flows for Bioenergy use in the European Union Thermie STR/1881/98-SE
Published 2002 by Kalmar University Department of Biology and Environmental Science Environmental Science Section SE-391 82 Kalmar, SWEDEN http://www.bom.hik.se/ess ISBN 91-89584-09-0 (This report, appendix C) ISBN 91-89584-06-6 (The main report)
This report is an appendix to the report “The Market Implication of Integrated Management for Heavy Metals Flows for Bioenergy use in the European Union”. The correct citation of this report is: Dahl, J. and Obernberger, I.: ’Country Report Austria’, p. 59. Appendix C in Johannesson, M. (ed.) et al.: 2002, The Market Implication of Integrated Management for Heavy Metals Flows for Bioenergy use in the European Union. Kalmar University, Department of Biology and Environmental Science, Kalmar, Sweden, p. 115.
2
Table of contents 1
Summary ...........................................................................................................................5
2
Introduction ......................................................................................................................7
3
Methodology......................................................................................................................9
4
General background data ..............................................................................................10 4.1 Geographical data, bedrock, climate and soil...........................................................10 4.2 Land use and population...........................................................................................10 4.3 Energy production and energy use ...........................................................................11 4.4 Use of Biomass energy .............................................................................................13 4.5 Energy policy and biomass potential in Austria.......................................................15 4.5.1 Energy Policy ...................................................................................................15 4.5.2 Potential biomass sources ................................................................................15 4.5.3 Potential usage of biomass ...............................................................................17
5
Present situation .............................................................................................................19 5.1 The flows of trace metals in Austria.........................................................................19 5.1 Em.............................................................................................................................21 5.2 issions and depositions of trace metals in Austria....................................................21 5.2.1 Emissions of Cd ................................................................................................21 5.2.2 Hg emissions.....................................................................................................22 5.2.3 Pb emissions .....................................................................................................22 5.2.4 Depositions of trace metals in Austria .............................................................23 5.3 Trace metals in soil...................................................................................................24 5.3.1 Concentrations of trace metals in arable soils.................................................24 5.3.2 Concentrations of trace metals in forest soils ..................................................25 5.4 Trace metals in mineral fertilisers, manure and sludge ............................................25 5.4.1 Mineral fertilizers .............................................................................................25 5.4.2 Manure..............................................................................................................26 5.4.3 Lime ..................................................................................................................26 5.4.4 Sewage sludge...................................................................................................26 5.4.5 Ash ....................................................................................................................27 5.5 Trace metals in food .................................................................................................27 5.6 Flows of heavy metals in arable land .......................................................................27 5.7 Flows of heavy metals in forest land ........................................................................28 5.8 Limiting values and guidelines.................................................................................29 5.8.1 Limiting emission values for combustion plants...............................................29 5.8.2 Trace metals in soil...........................................................................................29 5.8.3 The proper use of biomass ash on forest soil ...................................................30 5.8.4 The proper use of biomass ash on arable land.................................................31 5.8.5 Limiting values for sewage sludge....................................................................31 5.8.6 Limiting values for mineral fertilisers ..............................................................32 5.9 Costs and benefits.....................................................................................................32 5.9.1 Costs for disposal of ash...................................................................................32 5.9.2 Nutrient value of ash.........................................................................................32
3
5.9.3 5.9.4 5.9.5 6
Costs for preparing ash for ash utilisation.......................................................33 Costs for improved fractionation technology ...................................................33 Estimated value of Cadmium removed from arable soil ..................................34
Scenarios and case studies .............................................................................................35 6.1 6.2 6.3 6.4
Construction of scenarios .........................................................................................35 Bioenergy and biofuel scenarios...............................................................................35 Heavy metal flows in biomass combustion plants....................................................36 Results from scenarios calculated.............................................................................43
7
Summary and discussion of results...............................................................................49
8
Conclusions and recommendations...............................................................................54 8.1 8.2
9
Conclusions ..............................................................................................................54 Recommendations ....................................................................................................54
Literature ........................................................................................................................56
4
Summary This report discusses and describes the flow of trace metals in Austria today and for scenarios considered relevant for the future bioenergy system. Focus is on the trace metal cadmium (Cd), since this is a trace metal with high overall effect on human health and high biotoxicity. It is also readily available for uptake in plants and is therefore of great importance when considering the different aspects of a biomass energy system. Due to the Austrian legislations, Cadmiumverordnung (BGBI. Nr. 855/1993), the use of cadmium in pigment and PVC products are banned in Austria since in 1993 and the input of cadmium to the Austrian society are decreasing. The current main flow of Cd is the usage of Ni-Cd batteries. This flow is however, believed to decline as well, due to the introduction of more environmentally friendly alternative batteries. During combustion Cd (and Pb) are concentrated in the fly ash and flue dust particles and thus, if not precipitated in filters, emitted to the air. Small scale and medium scale biomass combustion units with less or no flue dust precipitation have thus been concluded to be the major contributors to the emissions of Cd in Austria. Large-scale units are required to be equipped with efficient fly ash precipitation units and the emissions of particles and trace elements from such plants are thus much lower. Furthermore, not only the emissions of trace elements are lower in large scale biomass plants compared to small and medium scale, but also a better management of trace metals can be achieved by implementing new developed combustion and trace metal fractionation technologies. By using the new combustion technologies toxic and volatile trace elements such as Pb and Cd are concentrated into a small ash fraction, while the main ash fraction is poor in these elements and can thus be utilised as a valuable fertilising material. The ash fraction with high concentrations of these trace elements is send for safe disposal and represents thus a separation of these elements from the environment. Austria is the most densely wooded land in Europe and consequently heating with wood is an important energy source, especially for residential heating in rural areas. The current annual utilisation of biomass for energy production in Austria is about 120 PJ primary energy /year and the potential is estimated to an additional 100 PJ primary energy /year. Due to the relatively high amount of Cd in Biomass compared to many fossil fuels, the predicted increase of biomass combustion is of great relevance for future Cd emissions. The case studies in this report revealed that depending on the future combustion technology used, biomass combustion could either be used as a process for separating Cd and Pb from the environment (best case) or a potential risk of becoming the single major domestic emitter of these elements instead (worst case). Thus, in order to avoid a worst case scenario , development of modern small scale stoves with efficient particle separation filters is necessary, or a change to district heating where the biomass is combusted in large to medium scale plants with efficient dust particle filters and implemented fractionation technologies instead. Although the current levels of heavy metals in Austrian arable soil are not considered to be exceptionally high, previous and current use of fertilisers and lime on arable land cause cadmium to accumulate in Austrian arable soil. However, results from scenario calculations revealed that by cultivating willow (Salix sp) on about 10 % of the total arable land in Austria (1 500 km2) the removal of cadmium due to uptake in willow crop would alone (3 825 kg/year) exceed the total influx of Cd to arable soil today (2 347 kg/year) and a net reduction of Cd from arable soil would be obtained. The general flows of cadmium in Austria forest soil were concluded difficult to calculate, due to large deviations between different locations. While the calculations performed in this study indicate a general net loss of Cd from forest soil (about 1 330 kg/ year), mainly due to 5
leakage, several other studies indicate local accumulation of Cd in forest topsoils, especially in high altitude alpine forest regions where the depositions are significantly higher than in lower regions. Another reason for this discrepancy is large deviations in soil composition which influence the mobility of Cd in the soil and thus the leakage factor. In areas with high accumulations an increased outake and utilisation of biomass is thus the best way of decreasing Cd from such regions. Cost–benefit calculations indicate a need for the development of new more cost effective and efficient filters for medium scale to small scale biomass combustion units. The current implementation of filters to such units is to expensive compared to the benefits estimated with current data.
6
2 Introduction The main purpose of this study is to illustrate the cadmium flow in Austria as a result of changed use of biofuels and to discuss associated environmental and health risks and possibilities. The report describes the flows of cadmium in Austria 1995 and scenarios considered relevant for the future bioenergy system. Domestic emissions of other environmentally relevant trace metals such as mercury (Hg) and lead (Pb) are also discussed, but the main focus is on cadmium (Cd). The Austrian study constitutes a part of the EU-financed research project STR-1881-98. The overall objective of the EU project is to make an assessment of the market implications of integrated heavy metals management for bioenergy use in the European Union. This is achieved by performing case studies of a selected number of countries (Sweden, Denmark, Austria, United Kingdom and France) showing the present situation of bioenergy use and trace metals flows. In addition, scenarios for the future, showing how the metal flows may change as a result from increased use of bioenergy, are constructed. Possibilities and risks to utilise bioenergy for cleaning of arable land is addressed. and in some cases even cleaning of contaminated industrial land is discussed (Riddel-Black et al., 1997). Based on the individual country reports and some key data from other EU-countries, it is the aim of the project to extrapolate the results achieved to the whole European Union. The amounts of heavy metals in Austrian soils are increasing. In forest this is mainly due to dry and wet deposition from air borne contaminants (Weiss, 1996; Zechmeister, 1995) while arable soils also experience high influxes by the use of fertilizers (BFL, 1997). The trace metal flows in the arable land and forest ecosystems are connected to the bioenergy production system by the plant uptake of trace metals, the use of biomass as fuel, and by recycling of ash. In addition to the efforts to reduce the input of trace metal to the soil, the outtake of biomass, for energy purposes, provides a way of removing trace metals from the ecosystem in areas were concentrations are considered to be to high (Narodoslawsky et al., 1996). In the first progress report of the project (Johanneson, 2000), cadmium was characterised as a metal of high risk and high biofuel relevance, due to its relatively high toxicity and the high plant availability. Lead and mercury are defined as metals with high general risk and moderate biofuel relevance (less plant available). Zinc is a metal with moderate general risk and high biofuel relevance, while arsenic in general constitutes a moderate risk and moderate biofuel relevance. The uptake and removal of cadmium from soil by the use of energy crops have been discussed and considered as a method for cleaning of arable soils. Willow (from the Willow (Salix sp) family) has a greater potential for accumulating cadmium than cereals, which make it interesting for this purpose (Riddel-Black et al., 1997). However, if the ash from the energy conversion process is to be brought back as a fertiliser, the metal content needs to be low. Separation of metals from the ash can take place either during the combustion by special design of the boiler (Dahl et al, 2001)or in a post-combustion ash-treatment process. In the case study of Austria, there has been emphasis on making an assessment how the objectives in the biomass utilisation could be a possibility to clean the arable soils but also to decrease emissions to air from biomass combustion. Furthermore, a technical database containing data on fractionation of trace elements in different biomass combustion units was compiled by TUG. This database was provided to the other partners as a basis for the case studies performed.
7
The disposition of the report is as follows: In chapter 1 are the main results summarised. Chapter 2 (this chapter), presents the aims of this study and puts the study it in perspective to other studies within this area of research. Chapter 3 describes the multi scenario systems analysis approach used in the project. Chapter 4, gives some important background data of Austria, such as climate, land use, energy use and biomass potential. Chapter 5 describes the situation in Austria 1992-98 concerning the flows of some trace metals with focus on the heavy metal cadmium. The flows of cadmium in the society are described as well as the flows in the soil/biofuel/combustion system. Limit values, guideline values, targets and national goals etc are as well as some crucial costs figures concerning the biofuel combustion system also presented in chapter 5. Chapter 6 describes three scenarios for the future soil/biofuel/combustion system: A best case scenario, a worst case scenario and a most probable case scenario are constructed for 2010 and 2030. The main data elaborated in the scenarios are the future use of energy, biofuels and combustion/cleaning techniques. Results from the different case studies are compiled in figures that show the cadmium flows in soil/biofuel/combustion system. Chapter 7 discuss the risks and possibilities of changes in flow of cadmium in the soil/biofuel/combustion system as a result of different use of biofuels and cleaning techniques. Chapter 8 presents the main conclusions from the study and gives some recommendation for policymakers and others that have an influence on the future use of biofuels in Austria. In chapter 9 are the references listed.
8
3 Methodology The flows of heavy metals, and cadmium especially, are described at three levels First level shows the overall flow, i.e. all flows and storage (emission, deposition, import and export of products). This level makes it possible to compare the overall flows of metals with the flow in the bioenergy system today and in the scenarios. Second level is the flow and storage of trace metals in the agricultural and forestry system. Third level is the flow of trace metals in the biofuel energy system. The following four types of case studies are constructed: State of the art – a description of the situation in the country in 1995. The year 1995 was chosen to make sure that data are available and possible to compare. However, sometime it is was still difficult to find relevant data for 1995 and in these cases data from a year as close to 1995 as possible to was used instead. The most probable case relevant to bioenergy use in Austria 2010 and 2030– the development that is judged to be the most probable one. The best case relevant to bioenergy use in 2010 and 2030 in Austria – the combination of data that will result in the best outcome and give the overall biggest benefit. The worst case relevant to bioenergy use in 2010 and 2030 in Austria – the combination of data that constitute the most severe risk. The basic data that is collected for the studies should be used in: Mapping the bioenergy situation in 1995. Construction of different bioenergy scenarios covering the energy amount for the near future, year 2010, and on long term, year 2030. Construction of different biofuel scenarios for the years 2010 and 2030. Construction of different scenarios for biomass use and combustion technologies.
9
4 General background data 4.1 Geographical data, bedrock, climate and soil The Republic of Austria, situated in the heart of Central Europe, covers an area of 83 858 km². Three fourths of Austria is occupied by the alps which traverse from west to east of the country. The mountains are mainly in the west of Austria while the eastern and northern margins are flatter or gently sloping. The highest peak in Austria is the Grossglockner (3,798 m) in the west of Austria and the lowest point is Lake Neusiedl (115 m) on the eastern border to Hungary. (CIA, 2001) The bedrock in the northeast of Austria is dominated by the Bohemian granite mass while the northwest of Austria is dominated by lime rich soil.The Austrian Alps may be subdivided into a northern and a southern limestone range, each of which is composed of mountains. These two ranges are separated by a central range that is composed of crystalline rocks. North of this massive mountain range, which forms the physical backbone of the country, lies a hilly subalpine region, stretching between the northern Alps and the Danube, while to the north of that river lies a richly wooded foothill area. The lowland area east of Vienna may be regarded as a western extension of the great Hungarian Plain (Encyclopædia Britannica Online. 2001) The climate is continental temperate, with cold winters and frequent rain in lowlands and snow in the mountains. The summers are cool with occasional showers. The wooded slopes of the Alps and the small portion of the plains of southeastern Europe are characterized by differing climatic zones. In the lowlands and the hilly eastern regions, the median temperature ranges from -0.9 °C in January to 20.3 °C in July. In those regions above 3 000 m , by contrast, the temperature range is between -11.3 °C, with a snow cover of about 3 m in January, and 2.1 °C in July, with about 1.5 m of snow cover. The prevailing wind is from the west, and the wetter regions of Austria are thus in the west and have an Atlantic climate with a yearly rainfall of about 1 000 mm; the eastern regions, in particular those under the influence of the drier, more continental type of climate, have less precipitation. (Encyclopædia Britannica Online. 2001) “The soils in Austria are approximately 6 000 years old, which means that particular consideration must be given to soil conservation. Conditioned by Austria's extremely diverse lithological structure, the sharp changes in relief and the varying climate, the soils also change over very short distances. Broadly speaking, in the Waldviertel and Mühlviertel areas there are predominantly silicate brown soils, brown podzolic soils and podzols, in the Northern Alpine foothills para-brown soils, gleysolic para-brown soils and Pseudogley soils and in the Southeastern Alpine foothills Pseudogley soils. High quality chernozems (steppeland black earths) occur in the Vienna Basin, in particular north of the Danube; in the southern part, chernozems and rendzinas on gravel predominate. Rendzinas also cover large areas of the Northern and Southern Limestone Alps, whereas podzolic and semipodzols covers much of the Central Alps. In the wide valleys there are extensive floodplain forest soils. In the Seewinkel area, one of the lowest areas in Austria, there are saline soils.” (Encyclopedia of Austria, 2001)
4.2 Land use and population. In 1995, Austria had a total population of about 8 047 000, and an population density of about 100 inhabitants per square kilometre (Statistic Austria, 2001). Austria is the most densely wooded land in Europe and forest make up about 42 % of Austria’s total area (Table 4.2a). The most common trees are conifer trees (69%), mainly spruce (56%) (Hauk, 1997). In Table 4.2a the use of land in Austria and in Table 4.2b, the production on arable land are displayed for year 1997. The data are displayed for 1997 as no such detailed data was found for the
10
reference year 1995. The dislocation of land use is however a slow process and the data from 1997 are consequently assumed to be relevant for 1995 as well. Table 4.2a: Land use (1997)
2
km 131974 91383 101051 816 341969 11426 81637 21300 21302 831858
Arable land Intensive grass land Extensive grass land (alpine pasture, etc. ) Other agricultural land (wine, fruit etc.) Forest Lakes and streams Alpine mountain Residental area Other (roads, etc.) Total area Source: (Wirtschaftkammer, 2001; BMFL, 1999)
Table 4.2.b: Arable land use (1997)
2
% 17 11 12 1 42 2 10 3 3 100
Crop Cereals Leguminous vegetables Root crops
km 81552 545 755
% 61.2 3.9 5.4
Industrial crops Fodder crops Fallow lands/ set aside Other arable crops Total Source: (EUROSTAT, 2000)
11132 21124 741 126 131974
8.1 15.2 5.3 0.9 100
4.3 Energy production and energy use The main part of the Austrian energy supply originates from fossil fuels and as Austria has no significant fossil fuel resources, about 2/3 (64.4 % in 1995) of the primary energy sources are imported (Table 4.3). Biomass and hydroelectricity are the dominating domestic energy carries as Austria does not use nuclear energy (Table 4.3a). According to the Austrian official statistic institute, (Statistic Austria, 1998), the contribution of biomass energy was, 1993, about 13.5 % of the total final energy use in Austria. This equalled about 117.5 PJ. However, (Obernberger, 1997) showed that this value was overestimated with about 1.8 % due to usage of incorrect density values for the biomass. The main part of the biomass utilised in Austria is softwood while statistic Austria calculates all biomass conversion with the density of hard wood. This error has not changed since 1993 and thus the amount of energy from biomass is typically overestimated in the literature based on these values. Furthermore, another difference between Statistik Austria and Obernberger is that Statistic Austria includes organic waste as biomass energy while this is excluded from the calculations of Obernberger. In this work mainly the results of Obernberger are used for case studies, although values of Statitik Austria is the more frequently used values in other investigations. Due to this, both figures based on Statistic Austria and the figures for 1995 corrected according to (Obernberger, 1999) are listed in Table 4.3a to Table 4.3d.
11
Table 4.3a: Annual primary energy supply by energy carrier (1995) PJ % 2 1 11 143 (120) Biomass 138 11 Coal 173 13 Hydro power 282 22 Natural gas 0 0 Nuclear power 523 41 Oil 26 2 Electricity 11285 100 Total Source: (E.V.A., 1998), 1: includes organic waste, 2: with corrections according to (Obernberger, 1997; 1999)
Table 4.3b: Domestic annual primary energy supply by energy carrier (1995) 1
Biomass Coal Hydro power Natural gas Nuclear power Oil Total
PJ 141 (117) 14 173 53 0 46 427
2
% 33 3 41 12 0 11 100
Source: (E.V.A., 1998), 1: includes organic waste, 2: corrections according to (Obernberger, 1997; 1999)
Table 4.3c: Annual final energy use in Austria by energy source (1995) PJ % 58 6 Coal 371 41 Oil 156 17 Gas 124 (110)2 14 Biomass 31 3 District heating 170 19 Electric energy 910 100 Total Source: (Austrian Biomass Association, 2000), 2: with corrections according to (Obernberger, 1997; 1999)
Table 4.3d: Annual final energy consumption by application (1995) PJ 351 Space heating and hot water 195 Process heat 87 Mechanical work 250 Mobility 27 Lighting and Electric devices (e.g. computers) 910 Total Source: (Austrian Biomass Association, 2000)
% 39 21 10 27 3 100
12
4.4 Use of Biomass energy With forest making up about 42 % of the landscape, Austria is among the most densely wooded countries in Europe, and wood or by-products from wood industry (such as bark and saw dust) makes up the main part of the biomass used for energy production. The current forest stock is estimated to 988 million m3 with a growth of about 27 million m3 annually. 20 million m3 of this is annually harvested and about 3.6 million m3 (23 %) are used as firewood. Other sources of biomass are black liqueur recovery combustion in the pulp and paper industry, bio-diesel produced from oilseeds as well as gas from landfills or biogas production. A small amount of biomass energy is also produced from combustion of straw. Table 4.4a shows the detailed distribution of primary and used biomass energy for 1993. No such detailed data was available for the year 1995 and thus the data of 1993 are used as a basis for the further case studies. Table 4.4a: Annual primary and finally used energy from biomass (1993) Primary energy PJ
Used energy (heat+el)
%
PJ
%
47.5
57
47.0
59
Bark
9.5
11
7.6
10
Straw
0.9
1
0.9
1
Fire wood
7.9
10
7.9
10
wood residues from forestry and industry
17.1
21
16.5
21
Total solid biomass Black liquor combustion in the paper and paper industry
82.9 18
100
79.8 15.3
100
Bio-diesel Landfill-, Sewage- and Bio-gas Total biomass
0.5 1.4 102.8
Waste wood
0.3 0.3
Source: (Obernberger I, 1997), combustible waste is not included
Table 4.4b: Annual primary energy from solid biomass utilisation by application (1993) Primary energy PJ Residential space heating by single or central heating boilers Industrial use District heating Total
%
Average energy efficiency %
Average full load hours hours/ year
59.6
72
65
1 600
21.0 2.3 82.9
25 3 100
80 80
6 500 1 650
Source: (Obernberger, 1997)
The major part (72 %) of the solid biomass is utilised in small scale residential single furnaces (tiled stoves, log stoves etc.) or central heating boilers (Table 4.4b) and mainly in rural areas where local supply of wood is utilized. In urban areas old wood fired heating systems are and have largely been replaced with systems based on fossil fuels (natural gas and oil) or district heating. This trend is continuing and the percentage of households using residential furnaces with firewood for their heating systems is decreasing (Table 4.4c).
13
Table 4.4c: Heating of households by energy carrier 1990 n
1995 %
n
1999 %
n
%
Wood
608
21%
572
18%
521
16%
Coal/coke
405
14%
215
7%
120
4%
Oil
781
27%
843
27%
925
29%
Natural gas
579
20%
777
25%
882
27%
Electricity
260
9%
312
10%
286
9%
District heating
231
8%
347
11%
444
14%
29
1%
56
2%
45
1%
100% 31123
100%
31223
100%
Others
21893
Total
n: number of thousands of households Source: (Austrian Biomass Association, 2000, Wirtschaftkammer Österreich, 2001)
The major reasons for this declining trend, is the comfort of gas- and oil- fired heating systems or district heating compared to old fashioned wood log fired systems. The declining trend in biomass usage for household heating is however partly damped by the fact that the heat from biomass in district heating system is increasing, but also by an expanding market of small scale automatically feed central heating wood boilers. Especially systems using wood pellets (Jonas et al., 2001) are showing a positive and growing trend since 1997 (Table 4.4d ) Table 4.4d: Annually installed number and total capacity of biomass boilers with automatic fuel feeding systems in Austria 19851992
199 3
10 234
199 4
199 5
199 6
199 7
199 8
199 9
2000
Sum numbers
Total capacity (MW)
1 443 1 479 1 579 2 280 2 027 1 913 2 058
2 149
23 859
425 1 323 2 128
3 466
7 342
1 175
Small scale
(£ 100 kW)
- wood chips/ wood log - pellets Medium scale
(100 to 1 MW)
1 272
134
151
172
214
256
280
159
223
2 701
778
154
15
20
23
34
45
50
42
27
391
888
1 592 1 650 1 774 2 528 3 178 4 889 6 515
9 331
41 635
2 841
Large scale
(> 1MW) Sum
11 660
Source: (Jonas et al., 2001)
Biomass-fired district heating networks in Austria have been developed and built in rural areas since the mid-eighties and this market has meanwhile seen a considerable and constant upturn. Approximately 6.2 PJ of district heat from 501 biomass combustion plants was in the beginning of year 2000 produced in Austria (Austrian Biomass Association, 2000) in comparison to about 2.3 PJ of district heat from 163 biomass combustion plants in the year 1993 (Table 4.4d). The main part of these plants are using wood based biomass fuels but in the reference year 1995, also 10 district heating plants combusting straw and energy crops were operative with a cumulated capacity of 20.4 MW.
14
4.5 Energy policy and biomass potential in Austria 4.5.1 Energy Policy Austria's energy policy, based on the principles of the IEA/OECD, is laid down in the Energy Reports of the Austrian Government (IEA, 1998; Rijpkema et al, 1997) Austria's energy policy objectives, reaffirmed in the 1993 and 1996 Energy report, include security of supply by reducing import dependency of fossil fuels, increase environmental compatibility and social acceptability. Priority is given to energy conservation, to increased use of renewable energy sources, and to a shift of emphasis from government interventions to market forces. Austria is very much in favour of energy from biomass. Despite the fact that energy from biomass is already an important energy source, the Austrian government has enacted a development plan for energy from biomass for the period 1995 – 2015, increasing the amount of biomass energy to 140 PJ per year. Increased renewable energy use is encouraged at both the national and provincial levels. Both the federal and provincial governments have responsibilities for aspects of energy policy. Both can enact energy legislation, and both are implementing measures to promote renewables. The main forms of support are capital investment subsidies, R&D measures, and support for renewable electricity production via favourable buy- back tariffs. The Government considers that waste still has considerable unexploited potential. Official energy research policy therefore stresses the need to concentrate efforts in this area. Besides long-term experiments involving energy cropping (cultivating and harvesting fast-growing plants) and the production of biogenic fuels, there have been projects to improve wood-fired systems, especially on a small scale. Austrian Government policy on renewables points out the macroeconomic advantages of biomass use, such as new possibilities in rural areas, and includes several schemes to promote small boilers and district heating systems. A series of measures were agreed by the Government to promote the use of biomass energy. They include: · · · · · ·
use of wood waste; promotion of energy cropping; increased use of biomass in district heating; promotion of biomass for process heat and in combined heat and power; promotion of biofuels; use of ethanol as a fuel component.
In view of the declining profit margin for traditional agricultural products, biomass also gains importance for farmers as an alternative source of income. Research projects on energy cropping are co-sponsored by the Federal Government and the provinces.
4.5.2 Potential biomass sources The potential biomass energy development has been estimated by several authers before (Rathbauer et al., 1999, Lechner et al., 1998), but show all different results according to the conditions they were based on. It is however not the aim of this project to compare and discuss all these estimations and thus it was decided to mainly use the potentials calculated by Obernberger (Obernberger, 1997). One of the reason for choosing this estimation was that most other predictions are based on the data from Statistic Austria (see previous discussion). Due to the large amount of forest in Austria, it is natural that the main biomass potential comes from increased forestry activities. At the moments only 63 % of the annual forest growth is harvested. The reason is partly due to topographic constrains but also due to
15
unfavourable economic conditions for a full utilisation. According to (Obernberger, 1997) the amount of biomass from forest could in short term easily be increased with 7 PJ per year by an increased usage of forest residues from large scale forestry (Table 4.5a). Another short term potential is a increased usage of straw reserves from the agricultural sector. This potential is estimated to be about 4 PJ per year. Table 4.5a: Short term biomass potential in Austria PJ per year 7
Firewood/ Forest residues from clean cuts
% 64
4 11
Straw Sum Source: (Obernberger, 1997)
36 100
The mean to long term biomass potential for energy production is estimated to be 100 PJ per year (Table 4.5b ). This potential comprises not only the short term potential use of forest residues but also a total increased harvest of forest, resulting in increased residual products from saw mills (saw dust, bark , etc.) as well as more forest residues from clean cuts. The total potential from an increased forest usage is estimated to be about 49 PJ per year. The use of short rotation crops on arable land is currently small in Austria. In 1995 it existed about 783 ha test fields with different kinds of test plants, although about 150,000 ha are estimated to be available comprising a potential energy of 30.9 PJ per year (based on a mixture of energy crops and short rotation forest with an average yield of 12 ton d.b./ha year). However, cheap fossil energy currently makes such short rotation cultivation non economical. The usage of straw is estimated to have a total mean to long term potential of 31 PJ per year. The calculations are in this case based on a return to old wheat sorts with longer stem increasing the combustible part of the straw. A survey among the farmers showed no hinder for such change provided there is a secure market for the straw (Obernberger, 1997). Table 4.5b: Mean to long term biomass potential in Austria PJ per year 7
Firewood / forest residues from clean cuts
49 13 31 100
Increased forest usage Straw Energy crops and short rotation forest Sum Source : (Obernberger, 1997)
16
% 7 49 13 31 100
4.5.3 Potential usage of biomass Based on biomass energy balances from 1993 and the average annually installed capacity between 1991 and 1995 Obernberger (1997) estimated the following yearly development for the future biomass utilisation (table 4.5c). Table 4.5c: Capacity potential for biomass combustion boilers in Austria (based on the development between 1991 to 1996)
Increase in capacity Water content Full load
[MW/year]
Efficiency
[%]
[wt %] [h/year]
Increased primary [PJ/year] energy Source: (Obernberger, 1997)
Bark and wood chip furnaces >1MW 0.11MW
55
28
37
34
53
19
35
44
43
46
101
112
116
105
91
Medium scale 0.1-1.0 MW
53
63
35
29
46
39
40
36
37
53
54
75
96
54
68
Small scale (wood chips)
