Agricultural and Food Science, Vol. 18 (2009): 347-365 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 347 © Agricultural and Food Science Manuscript received February 2009 Field biomass as global energy source Kaija Hakala, Markku Kontturi and Katri Pahkala MTT Agrifood Research Finland, Plant Production Research, FI-31600 Jokioinen, Finland, e-mail: firstname.lastname@mtt.fi Current (1997–2006) and future (2050) global field biomass bioenergy potential was estimated based on FAO (2009) production statistics and estimations of climate change impacts on agriculture according to emission scenario B1 of IPCC. The annual energy potential of raw biomass obtained from crop residues and bioenergy crops cultivated in fields set aside from food production is at present 122–133 EJ, 86–93 EJ or 47–50 EJ, when a vegetarian, moderate or affluent diet is followed, respectively. In 2050, with changes in climate and increases in population, field bioenergy production potential could be 101–110 EJ, 57–61 EJ and 44–47 EJ, following equivalent diets. Of the potential field bioenergy production, 39–42 EJ now and 38–41 EJ in 2050 would derive from crop residues. The residue potential depends, however, on local climate, and may be considerably lower than the technically harvestable potential, when soil quality and sustainable development are considered. Arable land could be used for bioenergy crops, particularly in Australia, South and Central America and the USA. If crop production technology was improved in areas where environmental conditions allow more efficient food production, such as the former Soviet Union, large areas in Europe could also produce bioenergy in set aside fields. The realistic potential and sustain- ability of field bioenergy production are discussed. Key-words: biomass, energy, food, global, potential, residues Introduction The global surface temperature has increased dur- ing the last century (1850–1899 to 2001–2005) by an average of 0.76 ºC. The warming has been especially rapid during the last decade, the pe- riod 1995–2006 being the warmest ever recorded (IPCC 2007a). The observed increase in average global temperature is mostly due to increases in anthropogenic greenhouse gas concentrations, the A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 348 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 349 most important of which is CO2 (IPCC 2007a). With increases in global temperatures, the entire global climate system has changed: precipitation has increased in northern Europe, eastern parts of North and South America and northern and central Asia, while it has decreased across the Sahel, the Mediterranean, southern Africa and parts of south- ern Asia (IPCC 2007a). Because of the differences in regional changes, the effects on agricultural production differ in different parts of the world. In general, small increases in temperature (under 3 ºC) will improve agricultural production at high latitudes (e.g. northern Europe, North America), but increases in temperatures as small as 1-2 ºC would worsen conditions at low latitudes (India, China, dry areas in Africa) (IPCC 2007b). On general, increases of temperatures higher than 3 ºC are projected to decrease global food produc- tion and food production at high latitudes will also be threatened, depending on the region (IPCC 2007b). At the same time, populations in areas with the highest vulnerability to climate change are projected to increase most (IPCC 2007b, United Nations 2007). Because of the obvious severity of the impacts of climate change, governments around the globe have agreed on measures to reduce greenhouse gas emissions. The best known agreement, the Kyoto protocol, was first adopted in 1997, and by the end of 2008 had been ratified by 177 coun- tries and the European Community. It entered into force on 16 February 2005. Industrialized coun- tries agreed on reducing (relative to year 1990) their greenhouse gas emissions by an average of 5% from the 1990 emission levels, during the pe- riod 2008–2012 (United Nations 1998), with 8% reduction assigned for EU (UNFCCC). Greenhouse gas emissions decreased by 7.7% in the EU-27 countries between 1990 and 2006. However, in the EU-15 group originally commit- ted to the Kyoto protocol, the decrease was only 2.7%. The projections for 2010 suggest, however, that the 8% target reductions will be met during the period 2008–2012, partly through use of the Kyoto mechanisms such as joint implementation or adoption of clean technology (EEA 2008). An important way to reduce greenhouse gas emis- sions is to use renewable energy sources. Sunlight, water flows, wind and biomass from forests and fields have always been used for different energy needs. Currently renewable energy sources make up only about 18% of all consumed energy, and traditional biomass energy 13% (REN21 2008). Thus, in 2004, when the global primary energy demand was calculated to be 464 EJ (Sims et al. 2007) the share of biomass energy in this figure was 44.6 EJ (altogether 9.6%), of which wood fuel comprised 39 EJ, agro fuels 4.2 EJ and mu- nicipal waste 1.1 EJ. However, the energy demand in 2050 will be about double compared to 2004 (baseline about 850 EJ and policy scenario of 2 ºC temperature increase about 810 EJ), and the assumed bioenergy potentials would be 270 EJ (wood fuel 57 EJ and agro fuels 213 EJ) in 2050 (evaluated with the VTT version of the ETSAP TIAM energy system model described in Koljo- nen et al. 2009). To efficiently contribute to miti- gation of climate change, EU has taken a further decision in December 2008, where the 27 EU countries are committed to further cutting their greenhouse gas emissions by 20% (compared with the 1990 level), increasing the share of renewable energy sources to 20% of all energy needed, and cutting energy use by 20% by 2020. In addition, 10% of transport fuel should originate from re- newable sources by 2020. When biomass production potential for bioen- ergy has been considered on basis of soil and cli- matic suitability, the possible energy crop produc- tion values have ranged from <100 EJ to >400 EJ (Berndes et al. 2003, Hoogwijk et al. 2005), even reaching 648 EJ when all land suitable for biomass production is used efficiently (Wolf et al. 2003). With technological development, and development of infrastructure, the bioenergy pro- duction figures presented e.g. for Africa (Hoogw- ijk et al. 2005) could be reached. However, much less is actually being produced at the moment, not even enough food, with the percentage of undernourished people remaining high in Africa (FAO 2009). Thus, looking at the present field crop production values gives a more realistic pic- ture of the crop production situation. Therefore, in the present simple survey based on FAO pro- A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 348 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 349 duction statistics (FAO 2009) we estimated the sufficiency of crop production at the moment and in the future (2050) and how much raw material for bioenergy, either as crop residues or specific bioenergy plants, could realistically be harvested from the field, taking into account the field area demand for food production. For the future we estimated how increases in population (United Nations 2007) and climate change would affect the production of field biomass energy. The world in this study is divided into 15 areas (Annex 1) according to the targets set by the umbrella project SEKKI, “The competitiveness of Finnish energy industry under developing climate policy” (Syri et al. 2008a). This project monitored the world- wide availability of energy now and in the future (2050), employing the global TIMES model (Syri et al. 2008b). The studied areas would normally be trading food among each other, but here they are for simplicity considered as independent units. For the future, the assumptions were that devel- opment will proceed according to the emission scenario B1 of IPCC (Nakicenovic et al. 2000, IPCC 2007a), that all arable land of the present day is used for field biomass production, and that field area does not increase. Emission scenario B1 was chosen, as efficient employment of renewable energy sources, including field bioenergy, aims at radical reductions of greenhouse gas emissions, as is also assumed in the B1 scenario of IPCC. Materials and methods Applying scenarios of climate change effects on crop production Crop production data were derived from FAO (2009). The production data were from 1997 to 2006 and averages from that period were used in calculations of food production, availability of arable area for bioenergy crops production and production potential of crop residues for bioen- ergy. Emission scenario B1 was used as the basis for the future climate, centred on year 2050. The B1 scenario assumes reduced emissions and only about 2 ºC increase in global average temperature by 2100, with about a 1.2–1.3 ºC increase in tem- peratures by 2050 (Nakicenovic et al. 2000, IPCC 2007a). The scenario is optimistic, but emission reductions are possible, especially if renewable energy sources become the preferred source, as planned for the EU-27, for example. In Europe (with the exception of the Mediter- ranean area) the impacts of climate change are expected to be rather small and mostly positive by 2050, if development proceeds according to emis- sion scenario B1 (Parry et al. 2004, IPCC 2007b). However, factors other than climate change are predicted to influence crop production dramati- cally. Thus, through technological development and plant breeding etc., crop yields could increase 1.7- (WEU), 2- (EEU) or 4- (FSU) fold, compared with current yields (Olesen and Bindi 2002, Ew- ert et al. 2005). As scenarios involving breeding and technological development together with cli- mate change effects are not available for all areas studied here, we follow the global scenarios of IPCC, interpreted by Parry et al. (2004) regard- ing changes in crop production under scenario B1 (multiplication coefficients in Annex 1). The changes (positive or negative) in production are relatively small (less than 10%). However, as sce- narios for technological development are avail- able for WEU, EEU and FSU, and the climatic conditions also favour development in these areas, we considered the estimates of Olesen and Bindi (2002) and Ewert et al. (2005) for field crop pro- duction developments in these areas as well. Calculation of crop residue potential The theoretical crop residue potential was esti- mated using yield, yield dry matter (DM) content and harvest index (HI) of each individual crop spe- cies (Annex 2). HI describes the share of harvested yield of the total biomass of a crop on a DM basis. Based on published literature and our own results, a single harvest index was chosen per crop and A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 350 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 351 the theoretical residue potential was calculated as: (1-HI) × yield DM)/HI. For calculation of the harvestable residue, or technical residue potential, the estimated biomass of the crop stubble left on the field as well as the residue lost through shedding of the straw material at harvest was reduced from the theoretical residue potential. For cereals, oil crops and pulses the stubble is normally 15–30 cm high, depending on crop and the harvesting conditions. According to Finnish research results, 15 cm barley (Hordeum vulgare L.) stubble represents about 27% of all straw biomass (Pahkala et al. 2007, Pahkala and Kontturi 2008). Studies of other cere- als reached similar conclusions (Staniforth 1979). The technical residue potential in this study is thus a product of the theoretical potential reduced by 30% for cereals, oil crops and pulses, 25% for grain maize (Zea mays L.) (Graham et al. 2007), and 50% for root crops including sugar beet (Beta vulgaris L. subsp. vulgaris). After determination of the technical crop residue potential of each individual species for the year 2006 (Table 1, Pahkala et al. 2009), the values were corrected according to the 10 year production averages (1997–2006) of the same crop groups (cereals, pulses, oil crops, root crops and sugar crops), and variation in residue potential was estimated according to the variation in production (Table 2). When crop residue production was estimated for the future (2050), the average technical residue potential values for 1997–2006 were corrected at group level for climate change effects (Annex 1). The resulting residue production figures for the future thus assume similar division of crop groups into individual crop species as at present. The energy value of each residue type was assumed to be 18 MJ kg-1 DM. Estimation of food sufficiency and availability of field for bioenergy crops Food sufficiency was estimated using the produc- tion statistics of FAO (2009). Grain equivalent (GE) values (on kg of wheat grain basis) were fitted for different crops, as described by Penning de Vries et al. (1997). In the calculation of GE, production quantities (averages of 1997–2006) of all cultivated crops listed in FAO statistics (FAO 2009) except temporary forage grasses were in- cluded in the total energy values for each of the 15 areas. Thus, in addition to cereals, pulses, oil crops, sugar crops and root crops, production of vegetables, fruits, nuts and fibre crops (hemp, flax, etc.) were also taken into account. Sufficiency of food production on arable land was then evaluated for each area for three different diets, vegetarian (GE usage 490 kg per capita per annum), moderate (860 kg) and affluent (1535 kg), using the United Nations population statistics. Estimation of food sufficiency in the future (2050) was based on United Nations estimations of population in the different areas (United Nations 2007) and estimations of changes in agricultural production (Parry et al. 2004) in the future (Annex 1). Before any of the areas were considered able to set aside field from food production, the GE required for each diet was doubled to cover yield fluctuations, storage losses (which can be substantial, particularly in developing countries) and other production uncer- tainties (Penning de Vries et al. 1997, Wolf et al. 2003). Food value of animal husbandry products relying solely on grazing was not taken into ac- count, as data for calculations of productivity of permanent pastures was not available for all the studied areas. Also game and fish were excluded from the calculations. Estimation of energy crop yields and energy values per hectare were done using average yields from 1997–2006 for each area, where enough land for energy crops was available. Energy crop spe- cies were chosen from typical crops grown or po- tentially grown in each area. The average yield levels (1997–2006) of the conventional grain/ seed crops and sugar cane were derived from FAO (2009) statistics, and the yields of special energy crops were taken from literature (Mischantus: Woods et al. 2006; reed canary grass: Pahkala et al. 2008; switchgrass: Schmer et al. 2008). The hypothesised share of the crop was used for as- sessing the total bioenergy of the crops (Table 3). For estimation of values in 2050, the effect of climate change was taken into account, as stated in Annex 1. A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 350 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 351 Ta bl e 1. P ro du ct io n (T g or m ill io n to nn es ) a nd th eo re tic al a nd te ch ni ca l c ro p re si du e en er gy y ie ld p ot en tia l ( E J ye ar -1 ) f or d if fe re nt c ro p ty pe s an d di ff er en t a re as in 20 06 . T he v al ue s fo r A U S ar e co rr ec te d to 1 0 ye ar a ve ra ge s, a s in y ea r 2 00 6 yi el ds w er e ex ce pt io na lly lo w in th at a re a. ce re al s oi l c ro ps pu ls es ro ot c ro ps su ga r c ro ps al l 20 06 Pr od . T g E J T he or . E J Te ch n. Pr od . T g E J T he or . E J Te ch n. Pr od . T g E J T he or . E J Te ch n. Pr od . T g E J T he or . E J Te ch n. Pr od . T g E J T he or . E J Te ch n. Pr od . T g E J T he or . E J Te ch n. A FR 14 5 2. 13 1. 52 46 1. 10 0. 77 11 0. 16 0. 11 21 6 0. 85 0. 04 98 0. 39 0. 39 51 6 4. 6 2. 8 A U S 34 0. 59 0. 40 3. 2 0. 11 0. 07 2. 1 0. 04 0. 03 1. 8 0. 01 0. 00 37 0. 15 0. 15 78 0. 9 0. 7 C A N 51 0. 83 0. 59 14 0. 39 0. 27 4. 1 0. 06 0. 04 5. 0 0. 02 0. 01 0. 9 0. 00 0. 00 75 1. 3 0. 9 C H I 44 5 6. 34 4. 53 83 2. 85 2. 00 5. 6 0. 08 0. 05 17 6 0. 56 0. 16 11 1 0. 44 0. 43 82 2 10 .3 7. 2 C SA 12 3 1. 70 1. 23 12 5 3. 12 2. 19 5. 2 0. 07 0. 05 56 0. 26 0. 03 61 3 2. 54 2. 54 92 1 7. 7 6. 0 E E U 81 1. 29 0. 92 9. 4 0. 25 0. 17 0. 6 0. 01 0. 01 17 0. 08 0. 04 25 0. 05 0. 02 13 3 1. 7 1. 2 FS U 15 4 2. 61 1. 84 25 0. 73 0. 51 2. 9 0. 05 0. 03 75 0. 33 0. 17 61 0. 12 0. 06 31 8 3. 8 2. 6 IN D 23 9 3. 51 2. 47 54 2. 46 1. 72 14 0. 32 0. 23 32 0. 15 0. 05 28 1 1. 17 1. 17 62 1 7. 6 5. 6 JP N 12 0. 15 0. 11 0. 3 0. 01 0. 00 0. 1 0. 00 0. 00 4. 0 0. 01 0. 01 5. 2 0. 01 0. 01 21 0. 2 0. 1 M E A 68 1. 13 0. 79 11 0. 28 0. 20 3. 0 0. 05 0. 03 12 0. 05 0. 03 26 0. 06 0. 04 12 0 1. 6 1. 1 M E X 32 0. 44 0. 32 1. 6 0. 04 0. 03 1. 7 0. 02 0. 02 1. 7 0. 01 0. 00 51 0. 21 0. 21 87 0. 7 0. 6 O D A 28 7 3. 81 2. 69 23 1 4. 24 2. 96 5. 1 0. 09 0. 06 72 0. 35 0. 03 18 5 0. 76 0. 76 78 1 9. 2 6. 5 SK O 6. 7 0. 08 0. 06 0. 2 0. 01 0. 00 0. 0 0. 00 0. 00 0. 9 0. 00 0. 00 0. 0 0. 00 0. 00 7. 8 0. 1 0. 1 U SA 34 7 4. 78 3. 51 11 0 2. 89 2. 02 2. 0 0. 03 0. 02 20 0. 09 0. 04 56 0. 17 0. 14 53 5 7. 9 5. 7 W E U 20 0 3. 25 2. 30 29 0. 57 0. 40 3. 5 0. 05 0. 04 42 0. 19 0. 09 98 0. 19 0. 10 37 3 4. 2 2. 9 w or ld 2 22 5 33 23 74 3 19 13 61 1. 0 0. 7 73 2 3. 0 0. 7 16 48 6. 3 6. 0 54 09 62 44 A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 352 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 353 Ta bl e 2. P ro du ct io n (T g or m ill io n to nn es ) a nd te ch ni ca l c ro p re si du e en er gy y ie ld p ot en tia l ( E J ye ar -1 ) f or d if fe re nt c ro p ty pe s an d di ff er en t a re as . A . A t p re se nt (v ar - ia tio n in 1 99 7– 20 06 ). B . I n 20 50 (v ar ia tio n ac co rd in g to v ar ia tio n at p re se nt ). A 19 97 –2 00 6 c er ea ls oi l c ro ps pu ls es ro ot c ro ps su ga r c ro ps pr od . T g E J te ch n. pr od . T g E J te ch n. pr od . T g E J te ch n. pr od . T g E J te ch n. pr od . T g E J te ch n. A FR 12 0– 12 9 1. 2– 1. 3 36 –3 8 0. 7– 0. 8 9. 2– 9. 9 0. 09 –0 .1 0 16 9– 18 1 0. 03 –0 .0 3 92 –9 5 0. 36 –0 .3 7 A U S 31 –3 6 0. 4– 0. 4 3. 0– 3. 4 0. 1– 0. 1 1. 9– 2. 4 0. 03 –0 .0 3 1. 8– 1. 8 0. 00 –0 .0 0 36 –3 8 0. 15 –0 .1 6 C A N 47 –5 0 0. 6– 0. 6 10 –1 2 0. 2– 0. 2 3. 2– 3. 7 0. 04 –0 .0 4 4. 5– 4. 8 0. 01 –0 .0 1 0. 6– 0. 7 0. 00 –0 .0 0 C H I 41 4– 43 2 4. 2– 4. 4 59 –6 3 1. 8– 1. 9 4. 9– 5. 3 0. 05 –0 .0 5 18 0– 18 4 0. 16 –0 .1 6 93 –9 9 0. 36 –0 .3 8 C SA 11 3– 12 0 1. 1– 1. 2 87 –1 01 1. 6– 1. 8 4. 4– 4. 7 0. 04 –0 .0 4 49 –5 1 0. 03 –0 .0 3 52 9– 55 7 2. 18 –2 .3 0 E E U 82 –9 0 0. 9– 1. 0 6. 1– 7. 2 0. 1– 0. 1 0. 7– 0. 8 0. 01 –0 .0 1 24 –2 8 0. 05 –0 .0 6 24 –2 6 0. 02 –0 .0 3 FS U 13 3– 14 8 1. 6– 1. 8 14 –1 6 0. 3– 0. 4 2. 7– 3. 0 0. 03 –0 .0 3 68 –7 1 0. 15 –0 .1 6 36 –4 2 0. 04 –0 .0 4 IN D 22 9– 23 6 2. 3– 2. 4 37 –4 0 1. 3– 1. 5 13 –1 4 0. 22 –0 .2 3 30 –3 1 0. 05 –0 .0 5 26 9– 28 4 1. 12 –1 .1 8 JP N 12 –1 2 0. 1– 0. 1 0. 2– 0. 3 0. 0– 0. 0 0. 1– 0. 1 0. 00 –0 .0 0 4. 3– 4. 5 0. 01 –0 .0 1 5. 3– 5. 5 0. 01 –0 .0 1 M E A 60 –6 5 0. 7– 0. 7 7. 4– 8. 0 0. 2– 0. 2 2. 6– 2. 8 0. 03 –0 .0 3 12 –1 2 0. 02 –0 .0 2 26 –2 7 0. 04 –0 .0 4 M E X 29 –3 0 0. 3– 0. 3 1. 9– 2. 2 0. 0– 0. 1 1. 4– 1. 5 0. 01 –0 .0 2 1. 5– 1. 6 0. 00 –0 .0 0 47 –4 8 0. 19 –0 .2 0 O D A 25 6– 27 2 2. 3– 2. 4 15 3– 17 2 2. 2– 2. 5 4. 8– 5. 1 0. 06 –0 .0 6 57 –6 3 0. 02 –0 .0 2 19 0– 19 9 0. 81 –0 .8 5 SK O 7. 0– 7. 3 0. 1– 0. 1 0. 2– 0. 2 0. 0– 0. 0 0. 0– 0. 0 0. 00 –0 .0 0 0. 9– 1. 0 0. 00 –0 .0 0 0. 0– 0. 0 0. 00 –0 .0 0 U SA 33 5– 35 1 3. 5– 3. 6 90 –9 5 1. 8– 1. 9 1. 6– 1. 8 0. 02 –0 .0 2 21 –2 2 0. 05 –0 .0 5 56 –5 9 0. 14 –0 .1 4 W E U 20 6– 21 3 2. 4– 2. 4 27 –2 8 0. 4– 0. 4 4. 4– 4. 9 0. 05 –0 .0 5 45 –4 7 0. 10 –0 .1 0 10 8– 11 3 0. 11 –0 .1 2 w or ld 20 74 –2 19 0 22 –2 3 53 2– 58 6 11 –1 2 55 –6 0 0. 71 –0 .7 7 66 7– 70 5 0. 7– 0. 7 15 11 –1 59 4 5. 5– 5. 8 B 20 50 A FR 11 4– 12 2 1. 2– 1. 2 34 –3 6 0. 7– 0. 7 8. 8– 9. 4 0. 09 –0 .0 9 16 0– 17 2 0. 03 –0 .0 3 87 –9 0 0. 34 –0 .3 5 A U S 32 –3 7 0. 4– 0. 5 3. 1– 3. 5 0. 1– 0. 1 2. 0– 2. 4 0. 03 –0 .0 3 1. 8– 1. 9 0. 00 –0 .0 0 36 –3 9 0. 15 –0 .1 6 C A N 52 –5 5 0. 6– 0. 7 11 –1 3 0. 2– 0. 3 3. 5– 4. 1 0. 04 –0 .0 5 5– 5 0. 01 –0 .0 1 0. 7– 0. 8 0. 00 –0 .0 0 C H I 39 3– 41 0 4. 0– 4. 2 56 –6 0 1. 7– 1. 8 4. 7– 5. 0 0. 04 –0 .0 5 17 1– 17 5 0. 15 –0 .1 5 88 –9 4 0. 34 –0 .3 6 C SA 10 7– 11 4 1. 1– 1. 1 83 –9 6 1. 5– 1. 7 4. 2– 4. 5 0. 04 –0 .0 4 46 –4 9 0. 03 –0 .0 3 50 3– 52 9 2. 07 –2 .1 8 E E U 74 –8 1 0. 8– 0. 9 5. 5– 6. 5 0. 1– 0. 1 0. 7– 0. 7 0. 01 –0 .0 1 22 –2 5 0. 05 –0 .0 6 22 –2 4 0. 02 –0 .0 2 FS U 12 0– 13 3 1. 4– 1. 6 13 –1 5 0. 3– 0. 3 2. 4– 2. 7 0. 03 –0 .0 3 61 –6 4 0. 13 –0 .1 4 33 –3 8 0. 03 –0 .0 4 IN D 21 7– 22 4 2. 2– 2. 3 35 –3 8 1. 3– 1. 4 13 –1 3 0. 21 –0 .2 2 28 –2 9 0. 05 –0 .0 5 25 6– 27 0 1. 06 –1 .1 2 JP N 13 –1 3 0. 1– 0. 1 0. 2– 0. 3 0. 0– 0. 0 0. 1– 0. 1 0. 00 –0 .0 0 4. 5– 4. 7 0. 01 –0 .0 1 5. 6– 5. 8 0. 01 –0 .0 1 M E A 57 –6 1 0. 6– 0. 7 7. 0– 7. 6 0. 2– 0. 2 2. 4– 2. 6 0. 03 –0 .0 3 11 –1 2 0. 02 –0 .0 2 24 –2 6 0. 04 –0 .0 4 M E X 28 –2 9 0. 3– 0. 3 1. 8– 2. 1 0. 0– 0. 1 1. 3– 1. 5 0. 01 –0 .0 1 1. 5– 1. 5 0. 00 –0 .0 0 45 –4 6 0. 18 –0 .1 9 O D A 25 6– 27 2 2. 3– 2. 4 15 3– 17 2 2. 2– 2. 5 4. 8– 5. 1 0. 06 –0 .0 6 57 –6 3 0. 02 –0 .0 2 19 0– 19 9 0. 81 –0 .8 5 SK O 7. 4– 7. 7 0. 1– 0. 1 0. 2– 0. 2 0. 0– 0. 0 0. 0– 0. 0 0. 00 –0 .0 0 1. 0– 1. 1 0. 00 –0 .0 0 0. 0– 0. 0 0. 00 –0 .0 0 U SA 31 8– 33 3 3. 3– 3. 5 85 –9 0 1. 7– 1. 8 1. 5– 1. 7 0. 01 –0 .0 2 20 –2 1 0. 04 –0 .0 4 53 –5 6 0. 13 –0 .1 3 W E U 21 7– 22 4 2. 5– 2. 6 29 –2 9 0. 4– 0. 4 4. 6– 5. 1 0. 05 –0 .0 5 47 –4 9 0. 10 –0 .1 1 11 3– 11 9 0. 12 –0 .1 2 w or ld 20 04 –2 11 6 21 –2 2 51 7– 56 9 10 –1 1 54 –5 8 0. 69 –0 .7 5 63 8– 67 4 0. 7– 0. 7 14 56 –1 53 6 5. 3– 5. 6 A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 352 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 353 Results Energy yield potential from harvestable crop residues The total production of different food crops with harvestable residue (cereals, oil crops, pulses, sugar crops, root crops) varied in the studied period 1997–2006 from 4.8 to 5.1 billion tonnes (Table 2). The biggest group was cereals, the production of which was about 2.1 billion tonnes year-1. The cur- rent technically harvestable residue energy potential of these crop groups is about 39–42 EJ at present, and 38–41 EJ in 2050 (Table 2). In practice, even the technical potential overestimates the real attain- able crop residue yield as some of the crop residue, in addition to the stubble, has to be ploughed in or left on the ground for better organic matter content and functionality of the soil. The amount needed for satisfactory soil functioning varies according to area and yield of the crop (Graham et al. 2007), and is not defined reliably enough for all the studied areas to be taken into account in this study. Table 3. Energy crops and their energy values (GJ ha-1) for areas where arable land is likely to become available for biomass production for energy. At present: variation in average production in 1997–2006. In 2050, variation is as- sumed to be relatively the same as at present. Area Crop Energy content MJ kg-1 Average bio- mass yield (tn ha-1) at present Share in the area Average energy content at present (GJ ha-1) in the area Average energy con- tent in 2050 (GJ ha-1) in the area AUS wheat 18 2.5–3.0 0.7 254–277 261–284 sugar cane 18 41.2–44.3 0.3 CAN rapeseed 26 3.0–3.2 0.3 100–108 110–119 maize 18 10.2–10.9 0.3 wheat 18 3.6–3.9 0.4 CSA sugar cane 18 32.4–33.6 0.7 437–453 416–431 soybean 26 4.3–4.6 0.3 EEU reed canary grass 18 3.0–7.0 0.2 86–124 77–112 miscanthus 18 7.0–12.0 0.2 rapeseed 26 4.5–5.0 0.4 sunflower 26 2.5–2.9 0.2 FSU reed canary grass 18 3.0–7.0 0.1 43–54 39–49 rapeseed 26 2.2–2.5 0.2 sunflower 26 1.8–1.9 0.4 barley 18 2.3–2.5 0.3 MEX sugar cane 18 36.1–36.7 0.7 474–483 450–459 soybean 26 2.9–3.0 0.3 USA maize 18 11.9–12.5 0.5 264–308 251–293 sugar cane 18 36.2–37.8 0.2 switchgrass 18 5.0–11.1 0.3 WEU reed canary grass 18 3.0–7.0 0.2 105–141 111–148 miscanthus 18 7.0–12.0 0.2 rapeseed 26 6.5–6.8 0.4 sunflower 26 3.1–3.2 0.2 A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 354 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 355 Food usage and availability of field area for bioenergy crop production The results show that enough food is produced at present in the world to satisfy the diet of every inhabitant, even without taking into account per- manent grassland productivity (Table 4a). The total global GE production, as calculated here, is at present (average of 1997–2006) 5.5 billion tonnes year-1 and the GE value per person is 824, which is approximately sufficient for a moderate diet (GE requirement 860, Penning de Vries et al.1997). In 2050, if only climate change effects and increase in world population (United Nations 2007) are taken into account, the total global GE production would be 5.3 billion tonnes year-1 and the GE per capita would be 575, which still would be sufficient for vegetarian diet for each inhabitant (GE requirement 490, Penning de Vries et al.1997) (Table 4b). If also technological development would be added to the calculations, the sufficiency of food would increase considerably. E.g. if only western Europe, eastern Europe and the former Soviet Union countries would reach yield levels possible for those regions, the GE value of world would be 6.8 billion tonnes by 2050, and would suffice for a mixed vegetarian-meat diet (GE 744 per capita) for everyone living in the world (results not shown). Food production is, however, not evenly distrib- uted. For example, South Korea (SKO) and Japan (JPN) are not self sufficient in food, but they are solvent enough to be able to import foodstuffs. The situation is more difficult in Africa (AFR), which is clearly deficient in food production, and will be more so in 2050 (Table 4). If considered only on the basis of the studied 15 districts, with no food trade assumed, fields could be set aside from food production for bioenergy crops both now and in the future in AUS, CAN, CSA, EEU, FSU, MEX and USA if a vegetarian diet were adopted (Table 4). With affluent diet, only AUS and CAN could still be producing bioenergy crops on fields. If an exercise is taken to look at technological develop- ment as above for Europe, filling the yield gap and positive effects of climate change in WEU would result in possibility of bioenergy production in this area as well (results not shown). If, however, food would be divided equally and food availability would be secured for everyone in a better world, no field area would be freed for bioenergy produc- tion, provided food is produced with the present technology and present crops. For the calculation of potentially produced bio- mass energy on set-aside fields, the energy values of the energy crops and their yields were calcu- lated per hectare (Table 3). The global gross yield of biomass energy from specifically cultivated en- ergy crops would be (with vegetarian diet) 83–91 EJ now and 64–70 EJ in the future (Table 4). The biggest producers of field energy crops for both the present and for 2050 would be AUS, CSA and USA. Positive technological development, e.g. ir- rigation in areas where water resources could be taken into use, might change the figures for the future dramatically. E.g., if the production technol- ogy in Europe alone would proceed according to the scenarios of Ewert et al. (2005) and Olesen and Bindi (2002), the global biomass energy potential would increase to 132 EJ (results not shown). The total field biomass energy potential is the sum of crop residue technical potential and bioen- ergy crop energy potential (Table 5). When this sum is used, all areas in the world are assigned a value. The biggest field energy producers would understandably be those that could produce most energy crop biomass (AUS, CSA and USA). The total energy yield from field biomass would be (if vegetarian diet would be assumed) 122–133 EJ now (1997–2006) and 101–110 EJ in 2050 (Table 5). Discussion Sustainability of residue collection for bioenergy Agricultural residues are one of the most reliable bioenergy sources for the future because they are always produced when crops are grown. In this study, A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 354 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 355 Ta bl e 4. R eg io na l a nd g lo ba l f oo d pr od uc tio n (e xc lu di ng g ra ss la nd a nd p as tu ri ng a ni m al s) in G E (g ra in e qu iv al en t, kg ) y ea r-1 A ) a t t he m om en t ( av er ag e of 1 99 7– 20 06 ) an d B ) in 2 05 0, th e ad eq ua cy o f th e pr od uc tio n fo r di ff er en t d ie ts , a va ila bl e fie ld a re a fo r bi oe ne rg y pr od uc tio n an d th e re su lti ng b io en er gy p ot en tia l i n E J pe r un it ar ea a nd y ea r. A re as w ith ou t a fi gu re a re n ot a bl e to p ro du ce b io en er gy c ro ps . A ll av ai la bl e ar ab le a re a is a ss um ed to b e us ed in b ot h 19 97 –2 00 6 an d 20 50 . B io en er gy cr op s ar e as su m ed to b e pr od uc ed o n th e se t a si de a ra bl e la nd a t t he s am e in te ns ity a s cr op s. v eg et .= v eg et ar ia n di et , m od er .= m od er at e di et , a ffl . = a ffl ue nt d ie t. A 19 97 –2 00 6 Po pu la tio n (m ill .) G E /a re a (* 10 9 ) G E p er ca pi ta E xt ra G E (* 10 9 ) E xt ra G E (* 10 9 ) E xt ra G E (* 10 9 ) Fi el d av ai la bl e m ill . h a Fi el d av ai la bl e m ill . h a Fi el d av ai la bl e m ill . h a E ne rg y pr od . E J E ne rg y pr od . E J E ne rg y pr od . E J ar ea ve ge t. m od er . af fl. ve ge t. m od er . af fl. ve ge t. m od er . af fl. A FR 96 4 46 7 48 5 A U S 25 19 7 79 03 17 3 15 4 12 1 43 38 30 11 –1 2 10 –1 1 7. 6– 8. 2 C A N 33 11 0 33 47 78 54 9. 1 32 22 3. 8 3. 2– 3. 5 2. 2– 2. 4 0. 4– 0. 4 C H I 13 36 59 3 44 4 C SA 46 2 11 87 25 72 73 5 39 3 73 39 32 –3 3 17 –1 8 E E U 11 9 12 9 10 86 13 3. 7 0. 3– 0. 5 FS U 28 5 37 6 13 19 97 52 2. 2– 2. 8 IN D 11 69 58 6 50 1 JP N 12 8 22 17 1 M E A 27 5 10 3 37 4 M E X 10 7 17 2 16 14 68 9. 7 4. 6– 4. 7 O D A 10 07 31 4 31 2 SK O 48 6 12 2 U SA 31 0 85 4 27 56 55 0 32 1 11 4 66 30 –3 5 18 –2 0 W E U 40 4 38 2 94 5 w or ld 66 71 54 98 82 4 17 13 92 2 13 0 32 7 16 6 34 83 –9 1 47 –5 1 8. 0– 8. 7 B 20 50 A FR 19 96 44 4 22 2 A U S 33 20 2 60 72 16 9 14 5 10 0 41 35 24 11 –1 2 9. 1– 9. 9 6. 3– 6. 8 C A N 43 12 1 28 31 79 48 30 18 3. 3– 3. 5 2. 0– 2. 1 C H I 14 18 56 4 39 7 C SA 63 2 11 28 17 83 50 8 40 53 4. 2 22 –2 3 1. 7– 1. 8 E E U 97 11 6 11 97 21 6. 9 0. 5– 0. 8 FS U 24 9 33 8 13 59 94 56 2. 2– 2. 7 IN D 16 58 55 7 33 6 JP N 10 3 23 22 4 M E A 45 6 98 21 4 M E X 13 2 16 3 12 35 34 5. 1 2. 3– 2. 4 O D A 15 10 31 4 20 8 SK O 42 6 14 7 U SA 40 7 81 1 19 94 41 3 11 1 90 24 23 –2 6 6. 1– 7. 1 W E U 41 4 40 1 96 7 w or ld 91 91 52 86 57 5 13 18 34 4 10 0 28 2 81 24 64 –7 0 19 –2 1 6. 3– 6. 8 A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 356 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 357 the estimated global technically harvestable crop residue energy potential was about 40 EJ at present and in the future. The figure corresponds well with that from previous studies (Lal 2005). However, the use of crop residues for energy depends on many factors other than technical harvesting potential. One of these is conservation of soil structure and its organic matter content. Crop residues left in the field improve the quality of soils. Crop residues on the field surface protect it from water and wind erosion. Residues improve soil structure and water filtration into the soil, and reduce evaporation, thereby improving Table 5. Total potential field bioenergy yield (EJ year-1) from primary agricultural residues and bioenergy crops for different diets now (variation in1997–2006) and in 2050 (variation according to that at present). Permanent grassland production is not included in calculations. veget. = vegetarian diet, moder.= moderate diet, affl. = affluent diet. Residues EJ Residues+Bioenergy crops EJ 1997–2006 veget. moder. affl. AFR 2.4–2.6 2.4–2.6 2.4–2.6 2.4–2.6 AUS 0.6–0.7 11–13 10–11 8.2–8.9 CAN 0.8–0.9 4.1–4.4 3.0–3.3 1.2–1.3 CHI 6.5–6.9 6.5–6.9 6.5–6.9 6.5–6.9 CSA 4.9–5.4 37–38 22–23 4.9–5.4 EEU 1.1–1.3 1.4–1.7 1.1–1.3 1.1–1.3 FSU 2.1–2.4 4.4–5.2 2.1–2.4 2.1–2.4 IND 5.0–5.3 5.0–5.3 5.0–5.3 5.0–5.3 JPN 0.1–0.1 0.1–0.1 0.1–0.1 0.1–0.1 MEA 0.9–1.0 0.9–1.0 0.9–1.0 0.9–1.0 MEX 0.6–0.6 5.2–5.3 0.6–0.6 0.6–0.6 ODA 5.4–5.8 5.4–5.8 5.4–5.8 5.4–5.8 SKO 0.1–0.1 0.1–0.1 0.1–0.1 0.1–0.1 USA 5.4–5.7 36–41 23–26 5.4–5.7 WEU 3.0–3.1 3.0–3.1 3.0–3.1 3.0–3.1 world 39–42 122–133 86–93 47–50 2050 veget. moder. affl. AFR 2.3–2.4 2.3–2.4 2.3–2.4 2.3–2.4 AUS 0.6–0.7 11–12 10–11 6.9–7.6 CAN 0.9–1.0 4.2–4.5 2.9–3.1 0.9–1.0 CHI 6.2–6.5 6.2–6.5 6.2–6.5 6.2–6.5 CSA 4.7–5.1 27–28 6.4–6.9 4.7–5.1 EEU 1.0–1.1 1.6–1.9 1.0–1.1 1.0–1.1 FSU 1.9–2.1 4.1–4.9 1.9–2.1 1.9–2.1 IND 4.8–5.1 4.8–5.1 4.8–5.1 4.8–5.1 JPN 0.1–0.1 0.1–0.1 0.1–0.1 0.1–0.1 MEA 0.9–1.0 0.9–1.0 0.9–1.0 0.9–1.0 MEX 0.5–0.6 2.8–2.9 0.5–0.6 0.5–0.6 ODA 5.4–5.8 5.4–5.8 5.4–5.8 5.4–5.8 SKO 0.1–0.1 0.1–0.1 0.1–0.1 0.1–0.1 USA 5.2–5.4 28–32 11–13 5.2–5.4 WEU 3.1–3.2 3.1–3.2 3.1–3.2 3.1–3.2 world 38–41 101–110 57–61 44–47 A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 356 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 357 crops’ capacity to withstand dry periods better. Organic matter in crop residues also increases soil organic matter (SOM) content (Andrews 2006, Blanco-Canqui and Lal 2008), with further benefits for soil functioning. SOM is an important factor in soil fertility and it affects both physical and chemi- cal properties of the soil (Bot and Benites 2005, Griffin 2008). Typically SOM is 2% – 10%. If crop residue removal results in increased soil erosion and higher runoff rates this would greatly decrease SOM and nutrient content (Andrews 2006). Accurate instructions for crop residue manage- ment, based on experimental research, are not yet available. Most information is available in the US corn production area and for harvest of corn stover as bioenergy (Wilhelm et al. 2007, Varvel and Wilhelm 2008). According to these studies a safe amount of stover harvest depends on soil proper- ties (sensitivity to erosion), climatic conditions and biomass yield of the corn crop. If the yield of corn is low and no-till is not used, then all crop residues must be left in the field (Wilhelm et al. 2007). If no-till cultivation (growing crops without tillage) is used, 30% of crop residues can be harvested with- out danger of increased soil erosion (Lindstrom 1986, Andrews 2006). On average, only about 30% of the corn crop residues can be sustainably collect- ed in the USA for bioenergy or other uses without endangering soil fertility (Graham et al. 2007). In northern production areas, and if yields are high, up to 60% of corn stover can be safely harvested (Graham et al. 2007). In a Canadian study, 40% of wheat residue could be harvested in 2 years out of three without affecting soil productivity (Lafond et al. 2009). In cool climates, such as Finland, where the growing season is short and crop residues on the soil surface can reduce crop yields by slowing soil warming, their removal at least partly could even enhance yield formation. In this study the technical biomass potential (harvestable biomass) was estimated by subtract- ing the portion of the crop left in the field at har- vest (stubble and shed straw) from theoretical biomass potential. The calculation of sustainable biomass potential would require valid estimates of the amount of crop residue needed to retain soil fertility. As there is limited information concern- ing the amounts of crop residue needed to sustain soil fertility, numerical estimates of the sustainable biomass potential are not given in this report. Ar- eas where crop residue removal is likely to impair soil fertility and cause erosion are those where water shortage currently limits crop production, and where the limitation will become more severe with climate change. These areas are IND, MEX, USA, AFR, AUS, MEA, CHI, and some countries in ODA (IPCC 2007b, Parry et al. 2004). In the northern hemisphere, where the climate is more humid, the extensive and sustainable use of crop residues for bioenergy is still possible. Food and bioenergy – prospects with and without fair share Global food production is sufficient for every individual now and will be in the future if develop- ment occurs in a sustainable manner as suggested by emission scenario B1 (Nakicenovic et al. 2000, Olesen and Bindi 2002, Parry et al. 2004, IPCC 2007a, IPCC 2007b). According to our results, however, the studied areas differ greatly in their self sufficiency. AFR has and will have difficulty producing adequate amount of food, especially given that its population will double from the current one billion to about two billion in 2050 (United Nations 2007). In some previous reports of food production sufficiency and possible bioenergy production, dif- ferent African regions were reported to be well able to feed themselves (Penning de Vries et al. 1997), and even to produce bioenergy crops (Berndes et al. 2003, Hoogwijk et al. 2005). Many of the stud- ies concerning biomass production estimates are, however, based on potential global production, not what is actually harvested. When seen in this way, the potential biomass production ranges from <100 EJ to >400 EJ (Berndes et al. 2003, Hoogwijk et al. 2005), even reaching 648 EJ when all land suitable for biomass production is used efficiently (Wolf et al. 2003). Our study is based on produc- tion values derived from actual global statistics, not production potential per se. Thus, the influence of political instability, underdeveloped infrastructure A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 358 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 359 and low technological development on a regional basis is taken into account in the actual production data (Table 2) and the resulting food sufficiency (Table 4). If permanent grassland production could be estimated, our study would probably have indi- cated higher GE and bioenergy production values. However, the present results seem realistic, at least for AFR, as the threat of increasing undernourished population in the area has been reported by the IPCC (IPCC 2007b). Fulfilling the need for food, and being able to produce bioenergy crops seems very unlikely for AFR without substantial technological progress occurring in the future. In order to efficiently produce energy from field biomasses, the choice of the energy crop is crucial. E.g. maize and sugar cane are very effi- cient biomass and energy producers given the right conditions, whereas huge potential lies in the vast areas of permanent grasslands that form 70% of all agricultural area and are at the moment not ef- ficiently used. For full exploitation of maize for bioenergy, taking into account that it also is used as food, its yield as well as the conversion of the yield and biomass to bioethanol has to be improved (Torney et al. 2007). The same demands apply to permanent grasslands, where improvement of pro- ductivity largely depends on adequacy of nutrients, water and transport logistics. Sugar cane production for energy in suitable climates and areas could increase the energy yield from agricultural areas considerably. E.g. in Brazil, the total agricultural area is 264 million hectares, of which permanent pastures comprise almost 200 million hectares (FAO 2009). The increase in sugar cane production area from 4.8 to 6.4 million hec- tares in 1997–2006 (FAO 2009) has according to Brazilian experts mainly taken place at the expense of the permanent pasture areas and small farms of varied crops with almost no impact on arable land (Goldemberg et al. 2008). Sugar cane production could still be increased on pasturelands, as the number of cattle km-2 is still very low and could be increased (Goldemberg et al. 2008). However, further increase in sugar cane production area in the coming decades may require deforestation and expansion to savannah (cerrado), which is an important natural habitat in Brazil. Luckily these kind of natural habitats are largely not suitable for intensive farming, because of soil quality, low pre- cipitation and logistics, and also local laws tend to protect natural habitats (Goldemberg et al. 2008). Usage of sugar cane and maize for bioenergy, while there still are areas in the world where popu- lation is undernourished has raised debate in pub- lic. Therefore, locally adapted natural plants such as Jathropa or castor bean could be taken into cul- tivation on large areas, provided their toxicity is reduced by breeding or genetic modification first (Gressel 2008). Genetic modification would also be required to improve cellulose biosynthesis and modify lignin content in lignocellulosic crops and straw to reduce the costs of lignin removal in this kind of biomass crops (Gressel 2008). In this study we were not able to take into ac- count international trade in foodstuffs. Thus, when JPN and SKO buy food, the GE overproduction will diminish in the areas providing that food. For example, Australia is a major wheat exporter and will most probably not start to produce bulk bioen- ergy crops on additional field area if it can export food profitably. Therefore, the bioenergy potential reported here has to be considered carefully. There is also danger of reduction in agricultural area. In Europe the arable land area is currently (average of years 2000–2005) 15% and the agricultural area, 30% lower than for the long-term average of 1977 to 1999 (FAO 2009). Some of this loss is attributa- ble to urbanisation, but some results from yield im- provement, technology development and reduced need for food production. Problems with land deg- radation can also occur. E.g. in Australia the agri- cultural area is decreasing because of drought and salinisation, but so far Australia has been able to keep the arable area constant (FAO 2009), probably with higher investments in technology. Conclusions According to our results total food production in the world should be just sufficient to provide a healthy diet for the entire population, both now and in the A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 358 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 359 future, even considering only arable farming (not permanent grassland). If food were distributed evenly, however, no field area would be avail- able for bioenergy crop production. Improvement of crop production technology and breeding for higher yields and better quality would increase the area freed from food production and improve the efficiency of energy production in these set aside fields substantially. Crop residues will always be a potential biomass energy source, but the extent of their sustainable use requires more information and studies that take local climate conditions into account. Acknowledgements. Financial support was provided by the Climbus Program of Tekes, the Finnish Funding Agency for Technology and Innovation, MTT Agrifood Research Finland, the Technical Research Centre of Finland (VTT) and Fortum, all of whom are gratefully acknowledged. 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Woods, J., Tipper, R., Brown, G., Diaz-Chavez, R., Lovell, J. & de Groot, P. 2006. Evaluating the sustainability of co-firing in the UK. Themba Technology Ltd and the Edinburgh Centre for Carbon Management. DTI Re- port URN 06/1960. 63 p. Cited on 11 November 2008. Available on the internet: http://www.berr.gov.uk/files/ file34448.pdf. A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 360 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 361 38−41 EJ vuodessa. Kuitenkin jo tällä hetkellä maan kasvukunnon ja kestävän viljelyn kannalta sopiva pois- korjattavien kasvintähteiden määrä riippuu ilmasto- ja viljelyoloista. Tulevaisuudessa ilmaston lämpeneminen kiihdyttää maaperän mikrobiologisia prosesseja ja siten yhä suurempi osuus korjuutähteistä on jätettävä pellol- le, jotta maaperän eloperäisen aineksen määrä säilyisi riittävänä. Tämän vuoksi nyt esitetyt korjuutähteiden käyttöluvut ovat vain teoreettisia ja niiden todellinen käyttömahdollisuus bioenergiaksi on näitä lukuja pie- nempi. Varsinaisten bioenergiakasvien viljelyä olisi näillä näkymin mahdollista lisätä Australiassa, Etelä- ja Keski-Amerikassa sekä USA:ssa. Jos viljelymenetel- miä pystytään tehostamaan ruoantuotannossa, ilmas- tolliset tekijät mahdollistaisivat bioenergiantuotannon lisäämisen myös entisen Neuvostoliiton valtioissa sekä suuressa osassa Eurooppaa. Peltobioenergian tuotanto on tämän tutkimuksen mukaan todellinen vaihtoehto fossiilisille polttoaineille. Tuotannon tehokkuus, kes- tävyys ja eettisyys riippuvat kuitenkin kasvintuotannon teknisestä kehityksestä, olojen vakaudesta ja siitä, saadaanko ruoka jaettua tasan maailman eri alueiden kesken. Jos maailman koko ruoantuotanto jaettaisiin tasan, ruokaa riittäisi sekä nyt että tulevaisuudessa kaikille − väestön kasvusta huolimatta, ja bioenergiak- sikin riittäisi peltobiomassaa, vaikka peltoalaa ei tällöin voitaisikaan valjastaa bioenergiakasvien tuotantoon. Jos tällaista tasajakoa ei toteuteta, suuri osa maailman maista voisi jo nyt, ja myös tulevaisuudessa, korvata merkittävän osan energiantarpeestaan peltobiomassasta saatavalla uusiutuvalla energialla. SELOSTUS Peltobiomassa globaalina energianlähteenä Kaija Hakala, Markku Kontturi ja Katri Pahkala MTT (Maa- ja elintarviketalouden tutkimuskeskus) Peltobiomassan nykyistä (1997−2006) ja tulevaa (2050) globaalia energiapotentiaalia arvioitiin FAO:n tuotantotilastojen avulla. Tulevaa potentiaalia arvioitiin Hallitusten välisen ilmastonmuutospaneelin (IPCC) päästöskenaarion B1 pohjalta. Tässä päästöskenaariossa maapallon kasvihuonekaasupäästöjen ja väestön kasvun ennustetaan vähitellen laskevan. Tähän kehitykseen vai- kuttavat uusiutuvien energialähteiden käyttö ja yhteistyö valtioiden välillä. Tutkimuksessa arvioitiin erikseen peltokasvituotannon sivutuotteista (olki, naatit jne.) saatava energiapotentiaali sekä ruoantuotannosta poistu- van ja bioenergiakasvien tuotantoon siirtyvän peltoalan biomassan tuotosta saatava energiapotentiaali. Yhteensä peltobiomassaan sisältyvä energiapotentiaali olisi tällä hetkellä 122−133 EJ (EJ=J×1018), 86−93 EJ tai 47−50 EJ vuodessa, jos väestön ruokavalio olisi (vastaavassa järjestyksessä) kasvis-, seka- tai lihapainotteinen ruoka- valio. Määrät ovat merkittäviä, sillä esimerkiksi Suomen koko energiankulutus vuodessa on 1,5 EJ ja maailman koko energiankulutus 464 EJ. Vuonna 2050 vastaavat peltobiomassasta saatavat teoreettiset energia-arvot olisivat 101−110 EJ, 57−61 EJ ja 44−47 EJ vuodessa ruokavaliosta riippuen (kasvis-, seka- ja lihapainotteinen ruokavalio). Vuoden 2050 arviot ovat pienempiä kuin nykyisen potentiaalin arviot, koska ilmastonmuutos heikentää suurilla tuotantoalueilla ruoantuotannon edellytyksiä muun muassa lisääntyvän kuivuuden takia. Lisäksi kasvavasta väestömäärästä johtuen yhä suurempi osa peltoalasta tarvitaan ruoantuotantoon. Peltokasvituo- tannon sivutuotteiden osuus pellolta saatavasta bioener- giasta voisi tällä hetkellä olla 39−42 EJ ja vuonna 2050 A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 362 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 363 Appendix APPENDIX 1. The studied areas, their coefficients for crop production for 2050 (in parentheses) and the countries they comprise. The division is based on the Global Times modelling approach used in the Finnish SEKKI project. AFR (0.95): Algeria, Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Congo, Congo, Democratic Republic of, Côte d’Ivoire, Dji- bouti, Egypt, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Libyan Arab Jamahiriya, Madagascar, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Niger, Nigeria, Réunion, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, South Africa, Sudan, Swaziland, Tanzania, United Republic of, Togo, Tunisia, Uganda, Zambia, Zimbabwe AUS (1.025): Australia and New Zealand CAN (1.1): Canada CHI (0.95): China CSA (0.95): Antigua and Barbuda, Argentina, Bahamas, Barbados, Belize, Bermuda, Bolivia, Brazil, British Virgin Islands, Cayman Islands, Chile, Colombia, Costa Rica, Cuba, Dominica, Dominican Republic, Ecuador, El Salvador, French Guiana, Grenada, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Jamaica, Martinique, Montserrat, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and Grenadines, Suriname, Trinidad and Tobago, Uruguay, Venezuela EEU (0.9): Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Hungary, Montenegro, Poland, Romania, Serbia, Serbia and Montenegro, Slovakia, Slovenia, The former Yugoslav Republic of Macedonia, FSU (0.9): Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Russian Federation, Tajikistan, Turkmeni- stan, Ukraine, Uzbekistan, , IND (0.95): India JPN (1.05): Japan MEA (0.95): Bahrain, Cyprus, Iran, Islamic Re- public of, Iraq, Israel, Jordan, Kuwait, Lebanon, Occupied Palestinian Territory, Oman, Qatar, Saudi Arabia, Syrian Arab Republic, Turkey, United Arab Emirates, Yemen MEX (0.95): Mexico ODA (1.0): Afghanistan, American Samoa, Bangla- desh, Bhutan, Brunei Darussalam, Cambodia, Cook islands, Fiji, French Polynesia, Guam, Indonesia, Kiribati, Korea, Democratic People’s Republic of, Lao People’s Democratic Republic, Malaysia, Maldives, Marshall Islands, Micronesia , Mongolia Myanmar, Nauru, Nepal, New Caledonia, Niue, Pakistan, Papua New Guinea, Philippines, Samoa, Singapore, Solomon Islands, Sri Lanka, Thailand, Timor-Leste, Tokelau, Tonga, Tuvalu, Wallis and Futuna Islands, Vanuatu, Viet Nam SKO (1.05): South Korea USA (0.95): United States of America WEU (1.05): Austria, Belgium, Belgium-Luxem- bourg, Denmark, Faroe Islands, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxem- bourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 362 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 363 A PP E N D IX 2 . H I a nd D M o f d if fe re nt c ro ps . N am e L at in n am e H I R ef er en ce s D M % R ef er en ce s C er ea ls sp ri ng b ar le y H or de um v ul ga re L . 0. 55 0. 49 1 ; [0 .5 2 (2 -r ow )– 0. 55 (6 -r ow )] 3 ; [0 .5 5– 0. 63 (U K ), 0. 33 –0 .4 9 (C an ad a) ]4 ; 0. 50 /0 .4 97 ; 0 .5 36 86 86 42 , 4 3 w in te r b ar le y H or de um v ul ga re L . 0. 55 0. 43 –0 .5 74 86 86 43 sp ri ng w he at Tr iti cu m a es tiv um L . 0. 45 0. 39 1 ; 0. 40 –0 .5 52 ; 0 .4 03 ; ( 0. 31 –0 .5 1, 0 .3 8– 0. 41 , 0 .3 7– 0. 47 )4 86 86 43 w in te r w he at Tr iti cu m a es tiv um L . 0. 45 0. 43 –0 .5 44 86 86 43 ri ce , w et la nd O ry za s at iv a L. 0. 55 0. 55 –0 .6 2 w ith s he ll 4 ; 0. 35 –0 .5 94 86 86 38 ; 8 5 44 oa ts Av en a sa tiv a L. 0. 50 0. 52 1 ; 0. 40 –0 .5 52 ; 0 .4 63 86 86 43 ry e Se ca le c er ea le L . 0. 40 0. 35 1 ; [0 .4 8( hy br ), 0. 39 (p op .)] 5 ; [H yb r 0 .4 0– 0. 52 , R iih i 0 .3 0– 0. 41 ]8 86 86 43 co rn , m ai ze Ze a M ay s L. 0. 55 0. 52 1 ; 0. 40 –0 .5 52 ; [ 0. 36 –0 .4 6, 0 .4 2– 0. 49 , 0 .4 7– 0. 57 ]4 86 86 –8 74 3 tr iti ca le Tr iti ca le 0. 45 0. 45 –0 .4 74 86 no re f ( es tim at ed 8 6) so rg hu m , b la ck m ill et So rg hu m b ic ol or (L .) M oe nc h 0. 50 0. 52 1 ; 0. 40 –0 .5 52 86 86 –8 74 3 ca na ry s ee d P ha la ri s ca na ri en si s L. 0. 23 0. 23 16 86 no re f ( es tim at ed 8 6) m ill et P an ic um m ili ac eu m L . 0. 50 no re f ( es tim at ed 0 .5 ) 86 86 –8 7 43 bu ck w he at F ag op yr um e sc ul en tu m M oe nc h. 0. 30 0. 19 /0 .4 97 ; 0 .3 01 4 . 86 86 P ul se s be an s P ha se ol us v ul ga ri s L. , V .fa ba 0. 55 0. 55 1 ; 0. 45 –0 .5 52 ; [ Ph as eo l: 0. 40 –0 .5 0] 31 89 89 –8 7 44 pe as P is um s at iv um L . 0. 50 0. 45 –0 .5 52 ; 0 .5 32 5 ; 0. 45 32 85 85 –8 6 39 ch ic kp ea C ic er a ri et in um L ., w in te r 0. 44 0. 28 –0 .3 64 ; 0 .5 22 5 ; 0. 33 1 ; 0. 44 32 86 no re f ( es tim at ed 8 6) co w pe a Vi gn a un gu ic ul at a L. 0. 54 [d et : 0 .4 4– 0. 64 in de t: 0. 15 –0 .2 9] 4 ; 0. 3– 0. 43 1 86 no re f ( es tim at ed 8 6) le nt ils Le ns e sc ul en ta M oe nc h. 0. 50 0. 45 –0 .5 52 ; 0 .5 72 5 ; 0. 46 32 86 no re f ( es tim at ed 8 6) fa ba b ea n Vi ci a fa ba L . 0. 55 0. 50 29 ; 0 .6 03 0 89 86 –8 93 9 ; 87 44 na rr ow -l ea fe d lu pi n Lu pi nu s an gu st ifo liu s L. 0. 42 0. 44 25 ; 0 .4 13 2 86 no re f ( es tim at ed 8 6) ve tc he s Vi ci a ss p 0. 45 0. 14 –0 .4 73 3 86 no re f ( es tim at ed 8 6) pi ge on p ea C aj an us c aj an (L .) M ill sp . 0. 50 no re f ( es tim at ed 0 .5 ) 86 no re f ( es tim at ed 8 6) O il cr op s su nfl ow er H el ia nt hu s an nu us L . 0. 40 0. 40 1, 28 ; 0 .3 0– 0. 35 2 91 no re f ( es tim at ed 9 1) lin se ed Li nu m u si ta tis si m um L . 0. 50 0. 56 ; 0 .1 6/ 0. 30 7 91 91 –9 24 4 oi ls ee d ra pe B ra ss ic a na pu s L. 0. 35 0. 22 –0 .3 84 91 91 –9 24 4 ca m el in a C am el in a sa tiv a (L .) C ra nt z 0. 35 0. 30 –0 .2 97 91 no re f ( es tim at ed 9 1) tu rn ip ra pe B ra ss ic a ra pa L . 0. 35 0. 27 –0 .4 69 91 91 –9 2 44 so yb ea n G ly ci ne m ax L . 0. 40 0. 42 1 ; 0. 25 –0 .3 52 ; 0 .3 5– 0. 53 4 ; 0. 46 28 89 86 –8 7 44 , 8 7– 90 45 ol iv es O le a eu ro pa ea L . 0. 70 [3 1k g dm /1 00 k g ol iv es ]1 0 30 30 10 A G R I C U L T U R A L A N D F O O D S C I E N C E Hakala, K. et al. Field biomass as global energy source 364 A G R I C U L T U R A L A N D F O O D S C I E N C E Vol. 18 (2009): 347–365. 365 gr ou nd nu ts A ra ch is h yp og ae a L. 0. 45 [s he lls 3 1% 0 .2 1] 17 ; 0 .4 52 6 ca st or o il se ed R ic in us c om m un is L . 0. 01 0. 01 18 91 no re f ( es tim at ed 9 1) m el on se ed C itr ul lu s vu lg ar is S ch ra d. 0. 25 0. 20 –0 .3 01 9 ( ac co rd in g to p um pk in s ee d) 91 no re f ( es tim at ed 9 1) se ed c ot to n G os sy pi um h ir su tu m L . 0. 31 0. 31 20 91 92 44 co tto ns ee d G os sy pi um h ir su tu m L . 0. 31 0. 31 20 91 92 44 sa ffl ow er s ee d C ar th am us ti nc to ri us L . 0. 30 0. 17 –0 .3 22 1 ; 0. 16 –0 .2 6 (0 .2 )2 3 ; 0. 38 24 91 92 4 4 se sa m e se ed Se sa m um in di cu m L . 0. 22 0. 21 –0 .2 32 2 91 no re f ( es tim at ed 9 1) oi l p al m fr ui t E la ei s gu in ee ns is J ac q. 0. 22 0. 22 34 35 35 34 R oo t c ro ps ca ss av a M an ih ot e sc ul en ta C ra nz 0. 55 0. 30 –0 .6 5; 0 .5 –0 .6 11 ; 0 .3 1– 0. 58 2 35 35 1 1 po ta to So la nu m tu be ro su m L . 0. 55 0. 55 1 ; 0. 47 –0 .6 24 30 21 –3 3 39 sw ee t p ot at o Ip om oe a ba ta ta s (L .) La m . 0. 68 [0 .6 8 dm % 27 ]1 3 ; 0. 25 15 ; 0 .5 4– 0. 70 37 27 24 –3 3 13 , 3 7 ta ro C ol oc as ia e sc ul en ta (L .) Sc ho tt 0. 90 0. 57 15 ; > 0. 90 27 ja m ss i D io sc or ea s pp . 0. 81 0. 81 46 40 33 38 Su ga r cr op s su ga r b ee t B et a vu lg ar is L . s ub sp . v ul ga ri s 0. 66 0. 66 35 21 24 41 su ga r c an e Sa cc ha ru m o ffi ci na ru m L . 0. 68 0. 66 35 49 49 3 5 ; 3 0– 31 40 References for APPENDIX 2 1. Bradford, J.B., Lauenroth, W.K. & Burke, I.C. 2005. The im- pact of cropping on primary production in the U. S. Great Plains. Ecology 86:1863–1872. Appendix A in Ecological Archives E086–098–A1. http://www.esapubs.org/Archive/ ecol/E086/098/appendix-A.htm. Cited on 3.9.2009. 2. www.bsyse.wsu.edu/cropsyst/manual/parameters/crop/ harvest.htm. Cited on 5.12.2007 and http://www.bsyse. wsu.edu/cropsyst/. Cited on 3.9.2009. 3. Peltonen-Sainio, P., Muurinen, S., Rajala, A. & Jauhiainen, L. 2008. 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Introduction Materials and methods Applying scenarios of climate change effects on crop production Calculation of crop residue potential Estimation of food sufficiency and availability of field for bioenergy crops Results Energy yield potential from harvestable crop residues Food usage and availability of field area for bioenergy crop production Discussion Sustainability of residue collection for bioenergy Food and bioenergy – prospects with and without fair share Conclusions References SELOSTUS Appendix