Use of material flow accounting for assessment of energy savings: A case of biomass in Slovakia and the Czech Republic

Energy Policy 39 (2011) 2824–2832

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Use of material flow accounting for assessment of energy savings: A case of biomass in Slovakia and the Czech Republic Radoslava Kanianska a,n, Tatiana Guˇstafı´kova´ a, Miriam Kizekova´ b, Jan Kovanda c a

´ Bystrica, Slovakia Slovak Environmental Agency, Tajovske´ho 28, 975 90 Banska ´dezˇnı´cka 36, 974 21 Banska ´ Bystrica, Slovakia Plant Production Research Centre—Grassland and Mountain Agricultural Research Institute, Mla c Charles University Environment Center, Jose Martiho 2, 162 00 Prague 6, Czech Republic b

a r t i c l e i n f o

a b s t r a c t

Article history: Received 4 June 2010 Accepted 14 February 2011

Anthropogenic material and energy flows are considered to be the major cause of many environmental problems humans face today. In order to measure material and energy flows, and to mitigate related problems, the technique of material flow and energy flow analysis has been conceived. The aim of this article is to use material and energy flow accounting approaches to quantify the amount of biomass that is available, but that so far has not been used for energy purposes in Slovakia and the Czech Republic and to calculate how much consumed fossil fuels and corresponding CO2 emissions can be saved by utilising this biomass. Based on the findings presented, 3544 kt/yr of the total unused biomass in Slovakia could replace 53 PJ/yr of energy from fossil fuels and 6294 kt/yr of the total unused biomass in the Czech Republic could replace 91 PJ/yr of energy. Such replacement could contribute to a decrease in total CO2 emissions by 9.2% in Slovakia and by 5.4% in the Czech Republic and thus contribute to an environmental improvement with respect to climate change. & 2011 Elsevier Ltd. All rights reserved.

Keywords: Material and energy flow analysis Biomass Energy savings

1. Introduction A socio-economic system and its natural surroundings are interconnected through material and energy flows. The consumption of materials from the environment is a necessary prerequisite for the production of goods and services and for maintaining and increasing standards of living. In keeping with the laws of thermodynamics, all consumed materials must be turned into waste and emission flows sooner or later and will be released back into the environment. For these reasons, anthropogenic material and energy flows are considered to be the major causes of many environmental problems humans face today (e.g., Fischer¨ Kowalski and Haberl, 1993; Weizsacker and Lovins, 1997; van der Voet et al., 2004). These problems include landscape changes, loss of biodiversity, acidification, eutrophication, global climate change and others. Material flow and energy flow analysis has been conceived to measure material and energy flows and to mitigate the related problems. The aim of these approaches is to monitor material and energy flows at various levels and to provide indicators that could contribute to resource management and output emission flows (OECD, 2008). One of the goals of the material and energy flow indicators is to quantify the total amount of energy needed for the functioning

n

Corresponding author. E-mail address: [email protected] (R. Kanianska).

0301-4215/$ - see front matter & 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.enpol.2011.02.055

of the human societies. This can be expressed either in mass or energy units and can be further subdivided into fossil fuels and renewable energy sources such as biomass and wind, water or solar energy. The aim of this article is to quantify the amount of available biomass that has not been used so far for energy purposes in Slovakia and the Czech Republic. A second aim is to assess what portion of the currently consumed fossil fuels and corresponding CO2 emissions can be saved by utilising this biomass. To reach the aim, we used approaches of the economy-wide material flow analysis (EW MFA). There are several reasons for using this approach. EW MFA is a method that recognises the increasing importance of environmental issues, material availability and efficiency and the difficulty of adequate management. Contrary to traditional system, EW MFA allows for a comprehensive view into the national economy including relationships between isolated systems or sectors (e.g., the agriculture and energy sectors). EW MFA is an asset for national planning, especially for natural resources, and allows for forecasting of future scenarios. It also allows for assessment of environmental problems caused by the economic activities of a nation and for determining how materially intensive is an economy. In addition, EW MFA mainly uses available statistical data. Eurostat has started to collect necessary data for EW MFA in all EU countries. The existing database is a great advantage because it allows for many calculations (e.g., unused biomass amounts) without additional expenses and data collection. Material flow accounting will be included in

R. Kanianska et al. / Energy Policy 39 (2011) 2824–2832

the regular EU environmental statistics. A proposal is under preparation for regulation by the European Parliament and the Council on European Environmental Economic Accounts. Thus, this common database and methodology will lead to representative and comparable results around the EU and possibly abroad. The rest of the article is organised as follows: Section 2 describes aims and targets in climate-energy policy. Section 3 describes the methodology (based on EW MFA) that was used for quantification of the excess existing biomass, and the approach by which biomass flows were converted from mass into energy units. Section 4 presents results and Section 5 discusses the results of our calculations and evaluates whether the spare biomass can be a substitute for a significant share of fossil-fuel consumption. The article is concluded in Section 6.

2. Climate-energy policy The replacement of fossil fuels with renewable energy sources is acknowledged to be beneficial from both environmental and economic points of view and with respect to global climate change. Global climate change is an on-going process that is driven by (among other factors) the CO2 emissions resulting from the combustion of fossil fuels (IPCC, 2007). The point of departure for a European energy policy is threefold: combating climate change, limiting the EU’s external vulnerability to providers of imported fossil energy, and promoting growth and jobs, thereby providing secure and affordable energy to consumers (EC, 2007a). The control of European energy consumption and the increased use of energy from renewable sources, together with energy savings and increased energy efficiency, constitute important components of the package of measures needed to reduce greenhouse gas emissions. Such reduction is necessary to comply with the Kyoto Protocol of the United Nations Framework Convention on Climate Change and with further community and international greenhouse gas emission reduction commitments beyond 2012. Increasing biomass energetic utilisation can be one of the tools for restructuring the energy system of the EU to a low-carbon model; this is one of the critical challenges of the 21st century (EC, 2007b). In March 2007, EU leaders endorsed an integrated approach to climate and energy policy that aims to combat global climate change and to increase the EU’s energy security, while at the same time strengthening its competitiveness. They committed to the concept of Europe transforming itself into a highly energyefficient, low-carbon economy. The EU Heads of State and Government set a series of demanding climate and energy targets to be met by 2020, known as the ’’20-20-20’’ targets. These are:

 A reduction in EU greenhouse gas emissions of at least 20% below 1990 levels.

 Fully 20% of EU energy consumption is to come from renewable resources.

 A 20% reduction in primary energy use compared with projected levels is to be achieved by improving energy efficiency. The integrated climate-energy package presented by the European Commission in January 2008 is a basic, comprehensive and very ambitious approach to reducing greenhouse gasses emissions, increasing energy efficiency, reducing the consumption of fossil fuels and supporting innovative, low-carbon technologies. The package includes the directives: 1. Directive 2009/28/EC (2009a) establishes a common framework for the production and promotion of energy from renewable sources.

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2. Directive 2009/29/EC (2009b) aims to introduce significant reductions in greenhouse gas emissions with a view to reducing the influence of such emissions on the climate. The Directive set out national overall targets for the share of energy from renewable sources in gross final consumption of energy in 2020 (14% for Slovakia and 13% for the Czech Republic). 3. Directive 2009/31/EC (2009c) establishes a legal framework for the environmentally safe geological storage of carbon dioxide (CO2) to contribute to the fight against climate change. In 2010, the German Advisory Council on Global Change (WBGU, 2010) recommended that the multilateral climate process be revitalised. According to WBGU, the EU should develop its 20-20-20 Agenda into a 30-20-20 Agenda by committing to reduce greenhouse gas emissions by 30% by 2020. The provision for 100% energy from renewable sources for Europe by the year 2050, combined with a pro-active energy efficiency strategy, could give international climate policy fresh momentum and at the same time put Europe’s competitiveness on a sustainable footing.

3. Methods and data There are various approaches and methods for the energy potential from biomass and efforts also exist to harmonise biomass resource assessment. The tendency is to combine Earth observation-derived data (e.g., Tomppo et al., 2008; Chen et al., 2009) with in-situ measurements based on common agricultural and forestry survey practices. As our aim was to quantify the biomass available for energy for entire countries, without changes in land use and land cover, we used economy-wide material flow analysis and economy-wide energy flow analysis. While the former quantifies material flows in mass units (kilotonnes), the latter transforms the material flows into energy units (Joules) by one specific method: calculating the total theoretical heat that can be produced in combustion, i.e., the gross calorific value of materials (EUROSTAT, 2001; Haberl, 2001a, 2001b). Our goal was to study the amount of energy that can be retrieved from available biomass using thermal conversion. Since thermal conversion usually expresses biomass input in mass units, we used economy-wide material flow analysis as the basis for our calculations. 3.1. Economy-wide material flow analysis As a follow-up to pilot studies such as Steurer (1992), Adriaanse et al. (1997) and Matthews et al. (2000), EW MFA became the first standardised analysis in the Eurostat methodological guide (EUROSTAT, 2001). Further standardisation was achieved through the Eurostat compilation guide (Weisz et al., 2007) and within the OECD work programme (which operated during 2004–2008) on material flows. Standardisation was finalised with the OECD guide to material flows and resource productivity (OECD, 2008). The aim of EW MFA is to quantify the physical exchange between a national economy, the environment and foreign economies based on the total material mass flowing across the boundaries of the national economy. The ultimate goal of the analysis is to obtain a material balance (Schandl et al., 1999). The most commonly used indicators that are based on EW MFA are the following: (1) used domestic extraction (DE), which includes all domestically extracted raw materials (such as fossil fuels, metal ores, non-metallic minerals and harvested biomass); (2) imports and exports (IM, EX), which include imports and

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exports of raw materials, biomass, semi-manufactured products and final consumption products; (3) direct material input (DMI), which is the sum of DE and IM; and (4) domestic material consumption (DMC), which is calculated as DMI minus EX. In order to present the results of the analysis, all materials included in the indicators were aggregated into five broader material categories and their related products: biomass, fossil fuels, metal ores, non-metallic minerals and other products. Domestic extraction consists only of materials used in the consumption and production processes. There are, however, other materials that are not really used, but that are transported from place to place in order to access deposits of raw materials, harvest crops or build housing and transportation infrastructures. The EW MFA is one of a few approaches that systematically account for these flows. Its goal is to take into account all material flows that can be related to environmental pressure. These flows are considered unused domestic extraction (UDE), and they include overburden from mining, biomass left in the field after harvest and excavations from construction activities. The UDE data statistic usually does not exist, but it can be calculated using various factors. We argue that it is suitable to use EW MFA as the method for our calculations because UDE related to crop harvest and logging comprises a major portion of spare biomass that can be used for energy purposes. Moreover, we also quantify the residual biomass from unmanaged permanent grasslands, which is not considered UDE by official EW MFA methodology. We did not take into account unused biomass from wood and food processing industries. 3.2. Data sources The data on domestic extraction, import and export of natural resources (including biomass) were collected for 2007 (the most recent available year). The data were retrieved from official publications and databases of an array of national organisations, in particular the Czech Statistical Office, the Statistical Office of the Slovak Republic, the Czech Geological Survey, Geofond and the State Geological Institute of Dionyz Stur, Geodesy and the Cartography and Cadastre Authority of the Slovak Republic (CSO, 2008b; SO SR, 2008; CGSG, 2008; ME SR and SGIDS, 2008; GCCA SR, 2008). Data sources generally covered the harvest of all types of primary crops, wood, and biomass extraction by fishing and hunting activities. For details on data sources, see Kanianska (2010), Kovanda et al. (2010) and Guˇstafı´kova´ (2006). Some items, in particular grazed biomass and crop and wood residues from harvest, are not estimated by official statistics. For these items, which usually are of considerable quantitative significance, we used standard estimation procedures according to EUROSTAT guidelines (Weisz et al., 2007; EUROSTAT, 2009). For residual biomass from unmanaged permanent grasslands, we used estimation procedures based on land data statistics (GCCA SR, 2008; MA SR, 2008) and on results from research on the productive potential of abandoned permanent grasslands (Gonda and Gadus, 2007; Kohoutek et al., 2009). 3.3. Calculation of domestic biomass extraction DE of biomass includes all biomass of plant origin extracted and used by humans and their livestock. It also includes fish harvesting and the biomass of hunted animals. Plant biomass includes primary crop harvest, fodder crop harvest, grazed biomass and crop residues. Good-quality data on the extraction of primary and fodder crops from arable land are provided by national statistical sources

and can be used directly for MFA compilation without further processing. Data on grazed biomass are poor. However, there exist other data from which grazed biomass data can be derived. Thus, the demand for grazed biomass was calculated based on the roughage requirements of ruminants and other grazing animals and on livestock numbers. European average factors for roughage uptake by livestock species are provided in Appendix A, Table A1. To estimate biomass uptake by grazing, total roughage uptake was reduced by the amount of available fodder crops and biomass harvest from grasslands. 3.4. Calculation of used and unused residues In most cases, the primary crop harvest is only a fraction of the total plant biomass of a given cultivar. The residual biomass, such as straw, leaves and stovers, is often subject to further economic use. Large fractions of crop residues are used as feed or bedding material in livestock husbandry. The used fraction of crop residues from cereals, rapeseed, soy beans, sugar beets and sugar cane is accounted for as DE. The used fraction is calculated by the harvest factor and the recovery rate (see Appendix A, Table A2). The harvest factor allows for the extrapolation of total available residue biomass from the primary crop harvest. The actual fractions of residues used are calculated from available crop residues by the recovery rate (see Appendix A, Table A2). Then, unused crop residues are simply calculated as the difference between available and used primary crop residues. Unused crop residues of other agricultural plants are calculated by coefficients ¨ and Giljum (2004) (see Appendix A, Table A3). according to Jolli We also quantified the biomass-related UDE from leftovers from timber logging. For timber we calculated UDE by multiplying DE for two timber categories (deciduous trees and coniferous trees) by coefficients that express the share of UDE in DE (see Appendix A, Table A4). 3.5. Calculation of residual biomass from unmanaged permanent grasslands With respect to grassland biomass, production was calculated as the average herbage and wood biomass production on unmanaged permanent grasslands. In Slovakia, the area of unmanaged permanent grasslands was calculated as the difference between the official data according to the Geodesy, Cartography and Cadastre Authority of the SR (GCCA SR, 2008) and the data according to the land parcel identification system (LPIS) reported by the Ministry of Agriculture of the SR (MA SR, 2008). According to the LPIS, verified areas are areas that are actually used as permanent grasslands. These areas are considerably smaller than areas of permanent grassland according to the GCCA SR. Average herbage and wood biomass production of abandoned grasslands was calculated according to the results of observations performed at five Cooperative Farms in Central Slovakia. The mean dry matter yield of permanent grassland biomass from abandoned areas was 2.2 t/ha/yr (Gonda and Gadus, 2007). The data of Kohoutek et al. (2009) were used to calculate residual biomass for unused permanent grassland areas in the Czech Republic. 3.6. Calculation of energy attainable from biomass-related UDE Biomass can be transformed into energy by several processes. For the calculation of energy production, direct combustion was used in this study. Jandacˇka and Malcho (2007) showed that the heating value of dry crop residues vary between 17.0 and 17.5 MJ kg 1, the dry wood residues between 18.4 and 19.2 MJ kg 1 and the dry

R. Kanianska et al. / Energy Policy 39 (2011) 2824–2832

grassland hay heating value is 17.4 MJ kg 1. Heating values depend on several factors, especially moisture content. Higher moisture content decreases heating values. Therefore, for our calculations we assumed average gross calorific values of 14.0 MJ kg 1 for crop residues, 15.0 MJ kg 1 for grassland hay and 17.0 MJ kg 1 for wood residues. 4. Results 4.1. Comparison of input material flow indicators for Slovakia and the Czech Republic with a focus on fossil fuels and biomass Taking into account the overall focus of this article, we concentrate on fossil fuels and biomass flows in this section. Fig. 1 shows the comparison of DE in Slovakia and the Czech Republic, and indicates that the difference in DE between Slovakia and the Czech Republic is, to a large extent, represented by the extraction of fossil fuels. This is significant in the Czech Republic, where fossil-fuel extraction is mostly extraction of brown coal and hard coal, while the extraction of crude oil and natural gas is only minor (Czech Geological Survey—Geofond, 2008). On the other hand, the extraction of fossil fuels is quite low in Slovakia and the fuels extracted are mostly crude oil and natural gas (Ministry of Environment of the SR, 2008). Per capita values of biomass DE are similar in Slovakia and the Czech Republic but are higher in Slovakia due to its overall higher levels of DE. In the next section of the paper, we discuss the potential for decreasing the use of fossil fuels (and their corresponding CO2 emissions) in the Czech Republic and Slovakia by biomass substitution. As argued in Section 3, UDE from biomass shows that the spare biomass that can be used for energetic purposes. 4.2. Domestic extraction of biomass In 2007, biomass accounted for 30% of total DE in Slovakia and for 19% of total DE in the Czech Republic. In the EU-27, biomass 100% Biomass

80%

Fossil fuels

60%

Metal ores

40%

Non-metallic industrial minerals

20%

Non-metallic costruction minerals

0% CR

Biomass

8 tons/capita/year

accounts for 25% of total DE. In Europe, the share of primary crops in the total harvest typically amounts to 30–40%, crop residues to 10–20%, fodder crops and grazed biomass to 30–40% and wood to 10–25% (EUROSTAT, 2009). In Slovakia in 2007, the share of primary crops in the total harvest amounted to 24%, crop residues to 14%, fodder crops and grazed biomass to 13% and wood to 43%. In the Czech Republic, the share of primary crops to total harvest amounted to 35%, crop residues to 20%, fodder crops and grazed biomass to 18% and wood to 27% (Table 1). The difference between the two countries can be explained by different land uses and topography. The share of agricultural land in 2007 was about 54% in the Czech Republic and 50% in Slovakia (Czech Statistical Office, 2007; Geodesy, Cartography and Cadastre Authority of the SR, 2008). In comparison with other European countries, Slovakia typifies a sub-mountainous and mountainous country (Ministry of Agriculture of the SR, 2008). This is the reason why the share of primary crops, crops residues, fodder crops and grazed biomass in total biomass DE was higher in the Czech Republic. On the other hand, the share of forested land was higher in Slovakia (41% as opposed to 34% in the Czech Republic), which explains the higher use of wood in this country. Fishing, hunting and gathering are of minor quantitative importance in both countries. Values of per capita per year biomass harvest in Europe averaged 3 t/cap/yr and ranged between 1 and 11 t/cap/yr (EUROSTAT, 2009). In Slovakia in 2007, the value of the per capita biomass harvest was 3.5 t/cap/yr and in the Czech Republic it was 3.4 t/cap/yr. 4.3. Used and unused residual biomass 4.3.1. Crop residues In 2007, 2846 kt/yr of used crop residues were produced in Slovakia. This represents 15% of the total domestic biomass extraction. There were 1934 kt/yr of unused crop residues, which account for 40% of the total available crop residues. According to Pepich (2007), 1823 kt/yr of unused crop residues suitable for energy purposes were produced in Slovakia in 2006. Although Pepich used different methods, this amount is comparable to the ¨ amounts calculated here, to those of EUROSTAT (2009) and to Jolli and Giljum (2004). Pepich used calculations based on crop area and calculated the average straw production per hectare minus the amount of straw used in livestock husbandry as feed (1.6 kg/livestock unit/day) and as bedding material (3.8 kg/live¨ and Giljum methods use stock unit/day). The EUROSTAT and Jolli data on real crop yields. In the Czech Republic, 7460 kt/yr of used crop residues were produced, which represents 20% of the total domestic biomass extraction. Unused crop residues totalled 5221 kt/yr, which is 41% of the total available crop residues (Fig. 2).

SR

9 7

Fossil fuels

6 5

Metal ores

4 3

Non-metallic industrial minerals

2 1

Non-metallic costruction minerals

0 CR

2827

SR

Fig. 1. DE in Slovakia and the Czech Republic in 2007.

4.3.2. Wood residues Unused biomass in forests can be divided into woody forest residues and primary timber processing mill residues. In this paper, we only calculate woody forest residues that remain in the forest and that are not used for energy production. These residues usually include branches with diameters of less than 7 cm. Primary timber processing residues are 100% recovered and combusted; thus no unusable residues exist from this source. As no data on unused residues in forestry is directly available, we used an average coefficient of 0.1 that was established by specialists from the Slovak National Forest Centre and the Czech Agricultural University. In 2007, wood residues amounted to 851 kt/yr in Slovakia and 982 kt/yr in the Czech Republic.

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Table 1 Domestic extraction of biomass in 2007 in Slovakia and in the Czech Republic (in kt/yr, in %). Type of biomass

Slovakia (kt/yr)

Slovakia (%)

Czech Republic (kt/yr)

Czech Republic (%)

A.1.1. Total primary crops A.1.1.1. Cereals A.1.1.2. Roots and tubers A.1.1.3. Sugar crops A.1.1.4. Pulses A.1.1.5. Nuts A.1.1.6. Oil-bearing crops A.1.1.7. Vegetables A.1.1.8. Fruits A.1.1.9. Fibres A.1.1.10. Other crops

4810 2793 288 847 12 1 466 308 44 0 51

25.78 14.97 1.54 4.54 0.06 0.01 2.50 1.65 0.23 0.00 0.27

13016 7153 998 2890 55 10 1145 282 362 2 119

36.17 19.88 2.77 8.03 0.15 0.03 3.18 0.78 1.01 0.01 0.33

A.1.2. Total crop residues, fodder crops and grazed biomass A.1.2.1. Crop residues (used) A.1.2.1.1. Straw A.1.2.1.2. Other crop residues (sugar, beet leaves and other residues) A.1.2.2. Fodder crops and grazed biomass A.1.2.2.1. Fodder crops A.1.2.2.2. Grazed biomass

5327 2846 2303 543 2481 1968 513

28.55 15.25 12.34 2.91 13.30 10.55 2.75

13081 7460 5639 1821 5621 2844 2777

36.35 20.73 15.67 5.06 15.62 7.90 7.72

A.1.3. Total wood A.1.3.1. Timber (industrial roundwood) A.1.3.2. Wood fuel and other extraction

8514 8070 444

45.64 43.26 2.38

9821 8843 978

27.29 24.57 2.72

A.1.4. Total fish capture and other aquatic animals and plants A.1.4.1. Fish capture A.1.4.2. All other aquatic animals and plants

2 2 0

0.01 0.01 0

0 0 0

0.00 0.00 0

A.1.5. Total hunting and gathering

5

0.02

70

0.19

18658

100.00

35988

100.00

A.1. Biomass

100% 80% 60% 40% 20%

tons/km2 of arable land/year

tons/capita/year

0.8 0.6 0.4 0.2

CR SR Unused crop residues Used crop residues

250 200 150 100 50 0

0.0

0%

300

CR SR Used crop residues Unused crop residues

SR CR Used crop residues Unused crop residues

Fig. 2. Used and unused crop residues in 2007 in Slovakia and in the Czech Republic.

4.3.3. Residual biomass from permanent grasslands In 2007, permanent grasslands covered an area of 880 920 ha and shared more than 30% of the total agricultural area in Slovakia (Geodesy et al., 2008). In the Czech Republic, permanent grasslands covered an area of 962 461 ha and comprised 27% of the total agricultural area (Czech Statistical Office, 2008a). In Slovakia, domestic extraction of biomass from permanent grasslands was 1403 kt/yr in total, of which 890 kt/yr was hay harvested from meadows and accounted for in DE as part of fodder crops. Grazed biomass from pastures was also accounted for in DE and represented 513 kt/yr. In the Czech Republic, domestic extraction of biomass from permanent grasslands (including grazing) was 2777 kt/yr (Czech Statistical Office, 2008b). In Slovakia, only 60%, and in the Czech Republic 97%, of total permanent grasslands area was managed. Several studies and ˇ grassland inventory surveys (Sla´vikova´ et al., 1996; Seffer et al., 2002) document the fact that semi-natural grasslands in Slovakia are threatened by the growth of shrubby and woody vegetation.

Uhliarova´ et al. (2005) reported that the most rapidly spreading woody species in Central Slovakia are Pinus silvestris, Populus tremula, Prunus spinosa, Rubus caesius and Picea abies and that afforestation depends on grassland utilisation as well as management of surrounding grassland areas. In 2007, afforested areas occupied around 20% of total permanent grassland areas in Slovakia. Productive potential of biomass from unused areas was determined by considering the botanical composition of permanent grasslands. Results of observations performed at five Cooperative Farms in Central Slovakia showed a mean dry matter yield of 2.2 t/ha/yr (Gonda and Gadus, 2007). Thus, the abandoned permanent grassland areas in Slovakia could produce 610 kt/yr of grass biomass. Results correspond with the findings of Pepich (2007) that afforestation has spread to 74 820 ha of unused permanent grassland areas in Slovakia. Afforested permanent grassland areas produced 150 kt/yr of unused woody biomass in Slovakia (Table 2). Finally, unused permanent grassland areas in Slovakia should produce a total of 760 kt/yr of biomass. In the Czech Republic on the other hand, only about 30 323 ha is

R. Kanianska et al. / Energy Policy 39 (2011) 2824–2832

Table 2 Permanent grasslands (PG) area and their biomass production in the year 2007 in Slovakia and in the Czech Republic. Source: Geodesy, Cartography and Cadastre Authority of the SR (2008), Ministry of Agriculture of the SR (2008), Czech Statistical Office (2008a).

Area Total PG area (ha) Used PG areas (ha) Unused PG areas (ha) Unused (afforested) PG areas (ha) Biomass production Total PG biomass production Grazed biomass and harvested hay from used PG areas (kt/yr) Potential biomass from unused PG areas (kt/yr) Potential biomass production from unused afforested PG areas (kt/yr)

SR

CR

880920 582502 277398 74820

962 461 932 138 30 323 –

2162 1403

2868 2777

610

90

150

–

classified as unused permanent grasslands. Abandoned grasslands in the Czech Republic produced 90 kt/yr of biomass with a dry matter yield of 2.98 t/ha/yr (Kohoutek et al., 2009). 4.4. Quantification of how much unused biomass-related energy could become available using conversion technologies In Slovakia in 2007, it would have been possible to use 3544 kt/yr (1933 kt/yr of crops residues, 851 kt/yr of wood residues and 760 kt/yr of PG biomass) of unused biomass. Unused biomass totals in the Czech Republic were 6293 kt/yr (5221 kt/yr of crops residues, 982 kt/yr of wood residues and 90 kt/yr of PG biomass). In Slovakia, unused crop residues represented 55%, wood residues 24% and unused biomass from PG 21% of the total unused biomass. In the Czech Republic, unused crop residues represented 83%, wood residues 16% and unused biomass from PG 1% of the total unused biomass. The total unused biomass production per capita was 0.7 t/cap/yr in Slovakia and 0.6 t/cap/yr in the Czech Republic. Because many factors affect these outcomes, it is not possible to give exact values for the amount of produced energy that was obtained by conversion technologies. For this reason, we used average gross calorific values identified in Section 3.6. Thus, the unused biomass in 2007 could have produced 53 PJ/yr of heat in Slovakia and 91 PJ/yr of heat in the Czech Republic. Of this, 27 PJ/yr of heat could have been produced from unused crop residues in Slovakia and 73 PJ/yr of heat could have been produced from unused crop residues in the Czech Republic. Unused biomass from permanent grasslands could produce 9 PJ/yr of heat in Slovakia and 1 PJ/yr of heat in the Czech Republic. From unused wood residues, 17 PJ/yr of heat could have been produced in both countries. In total, some 10 GJ/yr of energy per capita could be produced in Slovakia and 9 GJ/yr of energy per capita could be produced in the Czech Republic. 4.5. Savings in fossil-fuel consumption and reduction in CO2 emissions due to the use of available energy from biomass In Slovakia, total greenhouse gas emissions in 2007 represented 46 951 Gg/yr (excluding the LULUCF sector). This was a reduction by 35.9%, compared to the reference year of 1990. In the Czech Republic, total greenhouse gas emissions were 150 823 Gg/yr in 2007. The overall decrease since 1990 was lower than the decrease in Slovakia and amounted to 22.5%. This was caused by a lower decrease in the share of industry energy use in the Czech economy (EUROSTAT, 2010), as industries are usually more energy and

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carbon intensive than services. Moreover, the primary energy supply is still largely dependent on coal in the Czech Republic (Czech Statistical Office, 2009) and coal is more carbon intensive than natural gas or crude oil. In Slovakia, the main share of the aggregated greenhouse gases emissions comes from the power industry (75.7%) (Slovak Hydrometeorological Institute, 2010). In the Czech Republic, the share of the greenhouse gas emissions from the power industries is even higher than it is in Slovakia (81.8%) (Czech Hydrometeorological Institute, 2010). Based on thermal conversion of the fossil fuels used in 2007, 450 PJ/yr of heat was produced in Slovakia and 1524 PJ/yr was produced in the Czech Republic (Statistical Office of the SR, 2009; Czech Statistical Office, 2009). In 2007, produced, unused biomass from agricultural and forest systems could have replaced 53 PJ/yr (11.9%) of heat from fossil fuels in Slovakia and 91 PJ/yr (6.0%) of such heat in the Czech Republic. Such replacement could contribute to an important reduction in CO2 emissions. CO2 is the major combustion product of all biomass fuels and originates from the carbon content in the fuel. In 2007, 33 990 Gg/yr of CO2 was emitted from fossil-fuel combustion in Slovakia and 116 297 Gg/yr of CO2 was emitted from fossil-fuel combustion in the Czech Republic (Slovak Hydrometeorological Institute, 2010; Czech Hydrometeorological Institute, 2010). Replacement of these fossil fuels by unused biomass in combustion processes could reduce CO2 emissions by 4019 Gg/yr in Slovakia and by 6951 Gg/yr in the Czech Republic. Such replacement could contribute to a decrease in total CO2 emissions of 9.2% in Slovakia and of 5.4% in the Czech Republic.

5. Discussion Europe is increasingly dependent on imported fossil energy. According to ‘‘business as usual’’ scenarios, the EU’s energy import dependence will jump from 50% of total EU energy consumption today to 65% in 2030. Reliance on gas imports is expected to increase from 57% to 84% by 2030, and reliance on oil imports will rise from 82% to 93% (EC, 2007a). Doubling the share of biomass energy can improve the safety of the energy supply by decreasing the share of fossil fuels in the EU’s economy from 80% to 75% in 2010. In this case, 8% less crude oil will have to be imported (EC, 2005). The potential of sustainable biomass for bioenergy is assessed in many studies across the world, and the evaluation of ecological and environmental consequences of biomass utilisation for energy purposes is under serious discussion among scientists. WBGU (2008) estimated the technical energy potential of biogenic wastes and residues worldwide to be around 80 EJ per year. However, for soil protection and other reasons, the sustainable usable potential can be set at only about 50 EJ per year, of which around half may be economically viable. Lal (2006) estimated the amount of crop residues produced in the world at about 4 Pg, of which 2.8 Pg is from cereals. Fischer et al. (2010) assumed that agricultural residues from food and feed crops may provide an additional source for biofuel production in Europe (including the Ukraine). Up to 50% of crop residues can be used without risks for agricultural sustainability, food supply or nature conservation. In Austria, Haberl and Geissler (2000) found that the utilisation of currently unused biomass residues for energy generation could contribute some 76 PJ, (i.e., 6% of the current primary energy consumption in Austria) without increasing net primary production. In Switzerland, Steubing et al. (2010) showed that there is currently no sustainable potential for agricultural biomass, such as energy crops, crop residues and grasses. We found that the utilisation of currently unused biomass from crops residues, wood

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residues and permanent grasslands for energy generation could contribute some 53 PJ in Slovakia and 91 PJ in the Czech Republic. Lal (2005, 2006) pointed out that the use of crop residues as a possible source of feedstock for bioenergy production must be critically and objectively assessed because of its possible impacts on soil carbon sequestration, soil quality maintenance and ecosystem function. Even a partial removal (30–40%) of crop residues from the land can exacerbate soil erosion, deplete the soil organic carbon pool, accentuate emissions of CO2 and other GHGs from the soil to the atmosphere and exacerbate the risks of global climate change. The research done by Reicosky et al. (2001) and Gale and Cambardella (2000) focused on a comparison of corn grain to corn silage production over a 35-year period and showed that soil carbon does not depend on the presence of residues but is closely related to the choice of tillage system. According to their studies, a judicious combination of residue harvest and reduced tillage may jointly maintain soil carbon and increase producer profits. According to Kanianska et al. (2009), root residues are another important source of soil carbon. The proper soil management and green and organic manure application can contribute to sustainable biomass potential. Regarding biogeochemical cycles, a specific feature of ex-situ grass combustion is the fact that none of the carbon and nitrogen removed at harvest is returned to the grassland. These losses can be compensated by nitrogen fixation from the air via legumes and by carbon sequestration via sufficient biomass production (Soussana et al., 2004, Prochnow et al., 2009b). We assume that the residual unused biomass potential that we assessed in Slovakia and in the Czech Republic constitutes a sustainable source that could be used for energy purposes without adverse effects on ecosystems and the environment. There are several reasons for this statement. The assessed amount of unused biomass in national economies of Slovakia and the Czech Republic is related to the transformation to a market-based economy after 1989 and also to important changes in the agricultural and forestry sectors. Widespread changes in land ownership and decreases in agricultural support and subsidies resulted in marked decreases in cultivation in marginal areas (especially in upland and mountainous regions). On the other hand, the regrowth of new forests by natural processes has also been recorded. The sharp decline in livestock husbandry (in the case of cattle by almost 70% in Slovakia and 60% in the Czech Republic) has also caused decline in demand for forage and bedding. Economic and agrarian reforms have affected primary grassland function (via utilisation for forage production) and many large grassland areas were abandoned after 1989. Herbaceous and woody biomass from unused grasslands could be used for energy purposes. Removal of biomass from abandoned grasslands could result in improvement of the other functions and values of grasslands such as protection of the soil from wind and water erosion, soil fertility enhancement and biodiversity conservation (Peeters, 2009; Scimone et al., 2007). Moreover, Prochnow et al. (2009a) highlighted the fact that there are numerous suitable ways to use grassland biomass for producing energy and that solid biofuel production has the potential for positive impacts on grassland biodiversity. Richter et al. (2010) also showed new methods for utilisation of grassland biomass. With adequate support, it may be possible to use biomass from temporary, as well as from permanent, grasslands for the production of bioenergy. This could contribute both to the management of species-rich grasslands and to the production of renewable energy (EEA, 2007). The environmental impacts of the utilisation of biomass for bioenergy also depend on the technology used. Because they can be used as CO2-neutral raw materials, renewable resources will play a key role in future developments for sustainable industrial production and in efforts to curb the depletion of fossil resources (Dam et al., 2005). The CO2 emissions from biomass combustion are regarded as being CO2-neutral with respect to the greenhouse gas

effect. This is considered to be the main environmental benefit of biomass combustion (Van Loo and Koppejan, 2009). Prochnow et al. (2009b) also concluded that CO2 emissions can be considerably reduced with the use of grass combustion. Similarly, the impact of biofuels utilisation on the environment was evaluated by Searchinger (2010) who stated that the use of biofuels does not reduce emissions from energy combustion but may offset emissions by increasing plant growth or by reducing plant residues or other non-energy-related emissions. The efficiency and environmental safety of biomass utilisation is affected by the chemical composition and physical properties of the biomass used. Biomass from grasslands is difficult to exploit in conventional bioenergy-converting systems (Obernberger et al., 2006; Prochnow et al., 2005). Combustion of biomass from unused grasslands is less favourable than combustion of other crops or residues (such as straw) because of the higher nitrogen, sulphur, chlorine and potassium contents of grassland vegetation (Taube et al., 2007). However, Wachendorf et al. (2009) and Richter et al. (2010) showed that the integrated generation of solid fuel products and biogas from biomass (IFBB) may reveal new perspectives for grassland management and grassland utilisation for energy purposes and may also support the multiple functions that grasslands can provide to society.

6. Conclusions Based on the economy-wide material flow analysis and related indicators examined in this paper, the amount of unused biomass available for energy purposes was reported. The findings show that Slovakia and the Czech Republic have large amounts of biomass that is potentially available for energy purposes hidden in unused crop and wood residues and in residual biomass in permanent grasslands. In sum, 3544 kt/yr of unused biomass in Slovakia could replace 53 PJ/yr of heat from fossil fuels and 6293 kt/yr of unused biomass could replace 91 PJ/yr of heat from fossil fuels in the Czech Republic. Such replacement could contribute to a total decrease in CO2 emissions of 9.2% in Slovakia and of 5.4% in the Czech Republic and could thus contribute to an environmental improvement with regard to climate change. Removal of biomass from degraded grasslands could be a viable solution for utilising the energy potential of grasslands. In addition, it could support the restoration of the ecosystem services provided by grasslands and improve the overall quality of life for people in rural areas.

Acknowledgments The authors acknowledge the Slovak Research and Development Agency for the financial support given via contract No. APVV-0174-07.

Appendix A See Tables A1–A4. Table A1 Typical roughage intake by grazing animals in Europe (EUROSTAT, 2009). Livestock species

Average annual intake (t/head and year)

Cattle (and buffalo) Sheep and goats Horses

4.5 0.5 3.7

The values are given in air-dry weight and take into consideration the 5–20% range of the share of market feed in feed ratios.

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Table A2 Standard values for harvest factors and recovery rates for the most common crop residues used in Europe (EUROSTAT, 2009) Crops

Harvest factor

Recovery rate

Wheat Barley Oats Rye Maize All other cereals Rapeseed Soy beans Sugar beets

1.0 1.2 1.2 1.2 1.2 1.2 1.9 1.2 0.7

0.7 0.7 0.7 0.7 0.9 0.7 0.7 0.7 0.9

Table A3 Summary of the coefficients used for calculation of biomass-related UDE for other ¨ and Giljum, 2004). agricultural crops (Jolli Crops

Share of UDE in DE

Potatoes Beans, peas Lentils, lupins, vetches, pulses Hempseed, linseed, poppy seed, rapeseed Sunflower seed Cabbages, carrots, cauliflower, chillies, peppers, cucumbers and gerkins, garlic, green corn (maize), onions, peas, spinach Tomatoes Fresh vegetables(including okra) Apples Apricots Grapes, peaches, nectarines Pears, plums, strawberries Walnuts

0.36 1.40 1.90 1.26 1.89 0.45

0.90 0.45 1.80 0.90 1.80 0.90 1.80

Table A4 Summary of coefficients used for calculation of biomass-related UDE for timber. Timber

Share of UDE in DE

Coniferous trees Broad-leaved trees

0.1 0.1

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