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Albedo change during feedstock production can substantially alter the life cycle climate impact of bioenergy. Life cycle assessment (LCA) studies have compared the effects of albedo and greenhouse gases (GHGs) based on global warming potential (GWP). However, using GWP leads to unequal weighting of climate forcers that act on different timescales. In this study, albedo was included in the time-dependent LCA, which accounts for the timing of emissions and their impacts. We employed field-measured albedo and life cycle emissions data along with time-dependent models of radiative transfer, biogenic carbon fluxes and nitrous oxide emissions from soil. Climate impacts were expressed as global mean surface temperature change over time ( increment T) and as GWP. The bioenergy system analysed was heat and power production from short-rotation willow grown on former fallow land in Sweden. We found a net cooling effect in terms of increment T per hectare (-3.8 x 10(-11) K in year 100) and GWP(100) per MJ fuel (-12.2 g CO(2)e), as a result of soil carbon sequestration via high inputs of carbon from willow roots and litter. Albedo was higher under willow than fallow, contributing to the cooling effect and accounting for 34% of GWP(100), 36% of increment T in year 50 and 6% of increment T in year 100. Albedo dominated the short-term temperature response (10-20 years) but became, in relative terms, less important over time, owing to accumulation of soil carbon under sustained production and the longer perturbation lifetime of GHGs. The timing of impacts was explicit with increment T, which improves the relevance of LCA results to climate targets. Our method can be used to quantify the first-order radiative effect of albedo change on the global climate and relate it to the climate impact of GHG emissions in LCA of bioenergy, alternative energy sources or land uses.

Forestry will play an important role in a future bioeconomy, by providing wood fibres for biomaterial and bioenergy. However, there are contradictory opinions on the climate change mitigation potential of forestry. Stora Enso, an international forestry company, has the ambition to improve its climate impact assessment at corporate level. In this work, a system perspective was applied, where greenhouse gas emissions from value chains, biogenic carbon fluxes from forest land owned or leased by Stora Enso and temporarily stored in harvested wood products, and the substitution effect, i.e. avoided emissions from substituted products and energy were considered. Furthermore, new substitution factors for pulp and paper products were developed. The estimated climate effect at corporate level was a net removal of -11.5 million Mg CO2-eq yr-1 (i.e. a climate benefit) when considering value chain emissions, biogenic carbon fluxes from forest land and harvested wood products, and avoided emissions from substitution. Uptake of biogenic carbon counteracted around 40% of the value chain emissions, while the largest climate benefit (removal of 17.9 million Mg CO2-eq) was due to substitution of more greenhouse gas-intensive products. The new substitution factors developed for pulp and paper products were applied in the climate impact calculation at company level. Important assumptions and possible improvements for future studies were identified, e.g. how to assess the impact of cascading wood use in substitution calculations.

Background Use of bio-based diesel is increasing in Europe. It is currently produced from oilseed crops, but can also be generated from lignocellulosic biomass such as straw. However, removing straw affects soil organic carbon (SOC), with potential consequences for the climate impact of the biofuel. This study assessed the climate impacts and energy balance of biodiesel production from straw using oleaginous yeast, with subsequent biogas production from the residues, with particular emphasis on SOC changes over time. It also explored the impact of four different scenarios for returning the lignin fraction of the biomass to soil to mitigate SOC changes. Climate impact was assessed using two methods, global warming potential (GWP) and a time-dependent temperature model (∆Ts) that describes changes in mean global surface temperature as a function of time or absolute temperature change potential (AGTP). Results Straw-derived biodiesel reduced GWP by 33–80% compared with fossil fuels and primary fossil energy use for biodiesel production was 0.33–0.80 MJprim/MJ, depending on the scenario studied. Simulations using the time-dependent temperature model showed that a scenario where all straw fractions were converted to energy carriers and no lignin was returned to soil resulted in the highest avoided climate impact. The SOC changes due to straw removal had a large impact on the results, both when using GWP and the time-dependent temperature model. Conclusions In a climate perspective, it is preferable to combust straw lignin to produce electricity rather than returning it to the soil if the excess electricity replaces natural gas electricity, according to results from both GWP and time-dependent temperature modelling. Using different methods to assess climate impact did not change the ranking between the scenarios, but the time-dependent temperature model provided information about system behaviour over time that can be important for evaluation of biofuel systems, particularly in relation to climate target deadlines. Electronic supplementary material The online version of this article (doi:10.1186/s13068-017-0907-9) contains supplementary material, which is available to authorised users.

Background: Use of bio‑based diesel is increasing in Europe. It is currently produced from oilseed crops, but can also be generated from lignocellulosic biomass such as straw. However, removing straw affects soil organic carbon (SOC), with potential consequences for the climate impact of the biofuel. This study assessed the climate impacts and energy balance of biodiesel production from straw using oleaginous yeast, with subsequent biogas production from the residues, with particular emphasis on SOC changes over time. It also explored the impact of four different scenarios for returning the lignin fraction of the biomass to soil to mitigate SOC changes. Climate impact was assessed using two methods, global warming potential (GWP) and a time‑dependent temperature model (∆Ts) that describes changes in mean global surface temperature as a function of time or absolute temperature change potential (AGTP). Results: Straw‑derived biodiesel reduced GWP by 33–80% compared with fossil fuels and primary fossil energy use for biodiesel production was 0.33–0.80 MJprim/MJ, depending on the scenario studied. Simulations using the time‑dependent temperature model showed that a scenario where all straw fractions were converted to energy carriers and no lignin was returned to soil resulted in the highest avoided climate impact. The SOC changes due to straw removal had a large impact on the results, both when using GWP and the time‑dependent temperature model. Conclusions: In a climate perspective, it is preferable to combust straw lignin to produce electricity rather than returning it to the soil if the excess electricity replaces natural gas electricity, according to results from both GWP and time‑dependent temperature modelling. Using different methods to assess climate impact did not change the ranking between the scenarios, but the time‑dependent temperature model provided information about system behaviour over time that can be important for evaluation of biofuel systems, particularly in relation to climate target deadlines.

Locally produced bioenergy can decrease the dependency on imported fossil fuels in a region, while also being valuable for climate change mitigation. Short-rotation coppice willow is a potentially high-yielding energy crop that can be grown to supply a local energy facility. This study assessed the energy performance and climate impacts when establishing willow on current fallow land in a Swedish region with the purpose of supplying a bio-based combined heat and power plant. Time-dependent life cycle assessment (LCA) was combined with GIS mapping to include spatial variation in terms of transport distance, initial soil organic carbon content, soil texture and yield. Two climate metrics were used (global warming potential (GWP) and absolute global temperature change potential (AGTP)), and the energy performance was determined by calculating the energy ratio (energy produced per unit of energy used). The results showed that when current fallow land in a Swedish region was used for willow energy, an average energy ratio of 30 MJ MJ-1 (including heat, power and flue gas condensation) was obtained and on average 84.3 Mg carbon per ha was sequestered in the soil during a 100 year time frame (compared with the reference land use). The processes contributing most to the energy use during one willow rotation was the production and application of fertilisers (~40%), followed by harvest (~35%) and transport (~20%). The temperature response after 100 years of willow cultivation was -6·10-16 K MJ-1 heat, which is much lower compared with fossil coal and natural gas (70·10-16 K MJ-1 heat and 35·10-16 K MJ-1 heat, respectively). The combined GIS and time-dependent LCA approach developed here can be a useful tool in systematic analysis of bioenergy production systems and related land use effects.

Företaget Eco Etanol AB har utvecklat ett koncept där helgrödesensilerade ärt-eller åkerbönplantor processas i en stationär tröska för att separera bönan från grönmassan. Grönmassan valsas sedan för att utvinna en proteinrik pressvätska och en fiberrik halmrest, och bönorna mixas i vatten för att separera proteinet från stärkelsen. Denna process resulterar i tre fraktioner: protein, stärkelse och fiber. Dessa fraktioner kan förädlas till en mängd olika produkter. I denna studie antogs att halmen förädlas till bränslepellets medan proteinet i bönan och pressvätskan används som djurfoder och stärkelsen används för etanolproduktion. Konceptet som helhet kallas i denna studie för bioraffinaderiet. Klimatpåverkan av de tre produkterna studerades med hjälp av metoden livscykelanalys (LCA). Studien inkluderar odling, skörd och ensilering, transport från fält samt processande och förädling till färdiga försäljningsbara produkter, och slutar vid fabriksgrinden vilket innebär att distribution av varorna till slutanvändare eller användning av produkterna inte inkluderats. Studien inkluderar inte heller byggnader och övrig infrastruktur. Åkerbönans kvävelevererande och luckrande effekter i växtföljden har beaktats. De emissioner som uppkommer från odling och bioraffinaderi fördelas över de tre samprodukterna med hjälp av ekonomisk allokering. Det innebär att en produkt som har ett högt ekonomiskt värde får en högre miljöbelastning. Resultatet för respektive produkt jämfördes också med ett antal referensprodukter som har samma eller liknande funktion som de studerade produkterna. Referensprodukterna var för proteinfoder: värmebehandlat rapsmjöl ExPro ®, sojamjöl och drank, för etanol: etanol producerad från vete och sockerbetor samt bensin, för briketter: skogsflis, flis av gallringsvirke och pellets. Datainsamlingen bygger delvis på uppgifter från företaget Ecoetanol at Sweden AB bland annat vad det gäller skörd, tröskans kapacitet och energibehov samt näringsanalyser som beställts av Ecoetanol at Sweden AB och utförts av Eurofins Food & Agro Testing Sweden AB. Eftersom prototypen för bioraffinaderiet inte var färdigställd när denna studie genomfördes så baserades en stor del av beräkningen på data från litteraturen och delvis också på egna antaganden t.ex. vad gäller kapaciteten på bioraffinaderiet. Resultatet visade att dieselanvändning vid odling samt lustgasemissioner från åkermark har störst påverkan under livscykeln, båda respektive ca 30 % av den sammanlagda påverkan på klimatet. Energianvändning och insatsmedel i bioraffinaderiet hade relativt begränsad påverkan på klimatprofilen. Viktigt att notera är att egenproducerade briketter antogs användas för processens värmebehov, vilket täcker en betydande del av processens energibehov. Klimatpåverkan för proteinfodret, etanolen och briketterna samt referensprodukterna presenteras i tabell 1. Proteinfodrets klimatpåverkan uppskattades till ca 0,16 kg CO2ekv per kg torrsubstans (TS) proteinfoder, ca 50-68 % lägre än de undersökta referensprodukterna. Klimatpåverkan per liter etanol (21,2 MJ) uppskattades till ca 0,43 kg CO2ekv, ca 76 % lägre än bensin, men 2,5 % högre än veteetanol och ca 84 % högre än etanol gjord på sockerbetor. Klimatpåverkan per kWh briketter uppskattades till ca 16 g CO2ekv, vilket var nästan 1,4 gånger högre än flis från gallringsvirke och 19 % högre än pellets och 90 % högre än skogsflis.Årligen antogs ca 490 m3 etanol, ca 1000 ton proteinfoder och ca 5 600 MWh bränslebriketter produceras i bioraffinaderiet. Klimatpåverkan av den sammanlagda produktionen uppskattades till 462 ton CO2ekv per år. Detta kan jämföras mot referensprodukter med låg klimatpåverkan dvs. samma mängd produkter av sockerbetsetanol, flis från gallring och drank som ger upphov till ca 477 ton CO2ekv per år, eller referensprodukter med hög klimatpåverkan dvs. samma mängd produkter av bensin, sojamjöl och pellets vilket ger upphov till ca 1 440 ton CO2ekv per år. Ett antal känslighetsanalyser genomfördes. Störst påverkan på produkternas klimatpåverkan (+21%) gav en sänkning av skörden till normskörd samt förändrade antaganden vad gäller lustgasemissioner från kvävet i rot och skörderester (+27%). Jämförelsen mellan bioraffinaderiets årliga produktion och samma mängd referensprodukter påverkades mest om markkolsförändringar inkluderades i analysen av sojan. Det gav 73 % reduktion i klimatpåverkan för bioraffinaderiet jämfört med referensprodukter med hög klimatpåverkan. I grundanalysen var motsvarande reduktion 68 %. Sammanfattningsvis: att investera och driva det studerade bioraffinaderiet kan ge stora klimatvinster, men bara om det är miljöbelastande produkter som ersätts på marknaden. Om produkter med hög klimatpåverkan (fossila bränslen och sojamjöl) kan ersättas kan en minskning på ca 68 % uppnås. Om bioraffinaderiets produkter istället ersätter andra produkter som redan har en låg klimatpåverkan (bioetanol och drank) uteblir i princip vinsten (minskning med endast 3 %). Det är således viktigt att investeringen leder till en expansion av marknaden för produkter med låg klimatbelastning, och inte bara en inbördes omfördelning.

Syftet med detta arbete är att visa på möjligheter för det svenska jordbruket att bli försörjt med drivmedel även i en framtid, när oljan har blivit för dyr eller sällsynt för att kunna användas i tillräcklig omfattning. Detta projekt studerar möjligheterna att ersätta fossil diesel med första och andra generationens förnybara drivmedel, och omfattar drivmedel från råvaror med ursprung i både jord- och skogsbruk. De drivmedel som studeras är etanol, rapsmetylester (RME), biogas, Fischer-Tropsch diesel (FTD), dimetyleter (DME) och metanol. Arealbehov, energibalans och kostnader har beräknats. Studien visar att det finns tillräckligt med arealer i Sverige för att lantbruket ska kunna bli självförsörjande med drivmedel. För de drivmedel som baseras på grödor framförallt första generationens drivmedel) kommer dock mängden mat som är möjlig att producera att minska. Andra generationens drivmedel kan med fördel produceras från biprodukter som halm och matproduktionen behöver då inte minskas.

Efterfrågan på biobränslen ökar och utvecklingen drivs av både nationella och internationella mål att sänka utsläppen av växthusgaser samt att minska beroendet av fossil energi. Det har emellertid visat sig att inte all användning av bioenergi leder till minskade utsläpp av växthusgaser. För att säkerställa olika energisystems potential att minska utsläppen av växthusgaser behöver de jämföras med ett lämpligt fossilt referenssystem. I den här studien studerades skörd av grot (grenar och toppar) och stubbar i ett livscykelperspektiv för att identifiera system för skörd av skogsbränsle som relativt den producerade bränslemängden orsakar så små miljöeffekter som möjligt samtidigt som insatsenergi är liten. Användandet av skogsbränsle kan ses som en tidigareläggning av utsläpp av koldioxid jämfört med ett referensfall där biomassan lämnas kvar i skogen för att förmultna. Tidsperspektivet är därför betydelsefullt för hur förlusten av markkol ska beräknas för skogsbränsle som GROT och stubbar. För att beräkna den minskade inlagringen i markkol modellerades två granbestånd, ett i södra Sverige och ett i norra Sverige. Referensmarkanvändningen var skogsskötsel utan skörd av skogsbränslen. Två olika beräkningssätt användes för att beräknad den minskade inlagringen (i) medelvärde för kollagerförändringen över en tidsperiod samt (ii) lagerförändring mellan två tidpunkter. Tre olika tidsperspektiv utvärderades, 20 år, en omloppstid (118 år respektive 77 år) samt två eller tre omlopp (231 år och 240 år). Det senare för att kunna jämföra resultaten från bestånden i södra och norra Sverige. Resultaten visar att storleken på den minskade inlagringen i markkol per hektar beror av beräkningsmetodik, tidsperspektiv, skördeintensitet, områdets produktivitet och skördad resurs, d.v.s. stubbar eller grot. Utsläpp av växthusgaser från hela skogsbränslekedjan inklusive minskad inlagring av markkol ger olika resultat beroende på vilket beräkningssätt som används för markkol, lagerförändring mellan två tidpunkter (6-10 g CO2-ekv/MJ bränsle) eller skillnad i medelkolförråd mellan två tidpunkter (11-42 g CO2-ekv/MJ bränsle). Utsläppsminskning (d.v.s. klimatnyttan) genom att ersätta fossil energi med skogsbränslen beräknades. Det antogs att skogsbränslen användes i kraftvärmeverk och genom att allokera 52 % av miljöbelastningen på elen baserat på alternativallokeringsmetoden antogs elen ersätta elektricitet från kolkondenskraftverk samt naturgaskraftverk (kombikondens). Förutom de faktorer som påverkar inlagring i markkol beror skogsbränslens klimatnytta av effektiviteten i användningen, tillämpad fördelningsmetod av miljöbelastning och vilken energisort som ersätts. Den insatsenergi som behövts för att skörda, transportera och förädla skogsbränslet beräknades till 2–5 % av energin i det bränsle som levereras. Arbetet visar att effekterna av grot- och stubbskörd är fördelaktiga jämfört med fossilbaserade alternativ när det gäller såväl insatsenergi som utsläpp av klimatgaser på lång sikt. Insatsenergi är mycket liten och säkerställd medan de långsiktiga klimateffekterna är något osäkra som ett resultat av brist på kunskap när det gäller bland annat effekter av omrörning i skogsmarken vid stubblyftning. Studien indikerar alltså att skörd av grot i studerade systemtyper bör tillämpas om hänsyn tas till enbart insatsenergi och växthusgaseffekter. För stubbars växthusgasbalans krävs mer kunskap om vilken betydelse stubbskördens omrörning av marken har på nedbrytning av organiskt material. Skördetekniken av stubbar kan vara betydelsefull för växthusgasbalansen för stubbar. Studien behandlar inte andra effekter, exempelvis på biologisk mångfald eller skogens upplevelsevärde. Vid en samlad bedömning av om/var/hur grot- och stubbskörd bör tillämpas måste en helhetsbedömning ske där samtliga effekter inkluderas

The increased use of bio-materials for energy purposes is generating large amounts of ash. In most cases, e.g. during incineration of straw and grain, bottom ash contains small amounts of heavy metals, but significant amounts of the plant nutrients phosphorus (P) and potassium (K). Bottom ash also contains some micronutrients (e.g. copper and zinc) that are good for plants in small doses, together with generally small amounts of undesirable heavy metals, including cadmium. Biogas plants are becoming increasingly common in Sweden. They produce considerable amounts of digestate, a liquid fertiliser with a high content of nitrogen (N) comparable with that of pig slurry but lower contents of P and K. High quality biogas digestate may now be applied to arable land. This study investigated techniques and systems for blending and spreading liquid digestate with ash admixture. The physical and alkaline properties and solubility in water of some ash types were therefore studied at laboratory scale, as were the buffering properties of some digestates. The influence of ash admixture on digestate pH and ammonia emissions was also studied. At pilot scale, the properties of different ash/digestate mixtures were studied and a cell wheel for liquid manure was tested for adding the ash. Three types of ash (from oats, straw and wood pellets) and two types of digestate were studied. The ash produced so much dust that dust reduction measures and breathing masks proved necessary during handling. It also contained so much abrasive material that the risk of wear to pumps, pipes and other parts of the spreading equipment was rated high. It is therefore best if the ash can be added as late as possible to equipment for spreading on arable land, and also it can be prevented from passing through pumps and other moving parts. Only a minor proportion of the oat ash and straw ash was soluble in water. All three types of ash were alkaline and therefore increased the pH when mixed with water. However, the digestate had a high buffering capacity, so the overall effect on pH when moderate amounts of ash were included was slight. When oat ash was mixed into digestate, equilibrium concentrations of ammonia did not increase. There is thus no risk of increased ammonia emissions as long as the mixture does not contain more than 5% ash. In fact, ammonia concentrations were lower when ash was added, possibly because of ammonia binding to some metal ions. In practice, the SNFS 1994:2 limit values for P and heavy metals mean that the test ash-digestate mixtures with 1% by weight of ash can be applied to the same field at most twice in a three-year period. Mixtures with 3% by weight of ash can be spread at most every third year and mixtures with 5% by weight of ash at most every fifth year. Batch admixture of ash into liquid digestate is unsuitable, because the majority of the ash settles and forms sediment in the bottom of the tank, despite efficient stirring. For continuous dosage of finely pulverised ash into digestate, a cell wheel made for dosage of liquid manure can be used. However, for dosage into a flow under pressure a sluice is necessary to prevent digestate being pressed up into the ash container. Admixture of ash into solid digestate is another possible alternative, e.g. during movement of the solid fraction from a digestate separator to a store.

This study examines harvesting systems and presents conclusions on selection of machines for harvesting silage for dairy cows. Achieving a high quality cut of forage requires a high machine capacity and harvesting must be carried out at the optimal time with respect to plant growth stage. Therefore calculation of timeliness costs, which are determined by the time and capacity of harvesting, formed an important part of the study. These calculations require timeliness factors that describe the losses for each day by which harvest is delayed after the date of maximum economic crop value. The timeliness factors were calculated for each cut from data on changes in yield and quality of cuts during the harvest period. Harvesting cost calculations were based on a precision chop forage trailer, a precision chop forage harvester with separate transport trailers and a round baler with integral wrapping. Cost calculations were carried out for three different sizes of machine chain (small (S), medium (M) and large (L)) for each harvest system. The operations included were mowingconditioning, harvesting in the field, transport to storage and loading and packing into a bunker silo. Harvesting costs included the cost of machines, labour and timeliness. In addition, ensiling costs such as bale plastic and the investment, interest and maintenance cost for the bunker silo or the storage area for round bales were included when comparing the harvesting systems. Calculations were made for a three-cut system in conventional (CONV) and organic (ORG) forage production in southern Sweden (Gss) and central Sweden (Ss). When timeliness costs were not considered there was a risk of too low a harvest capacity being chosen. The effect of including timeliness costs when calculating harvesting costs increased with the forage area harvested, since a larger forage area increased the duration of harvest. Table S1 shows harvesting and ensiling costs with 1 km transport distance for 70 hectares of forage in conventional production and 90 hectares in organic production in central Sweden. At short transport distances (1 km), the precision chop forage trailer and the precision chop forage harvester with separate transport trailers had similar harvesting and ensiling costs, while those for round baling were somewhat higher. The precision chop forage harvester with 2 or 3 transport trailers resulted in the lowest costs at 2-7 km transport distance. At longer transport distances (>7 km), the round baler was the cheapest of the harvesting systems studied here. As regards machine capacity, it is clear from Figure S1 that to minimise harvesting costs the smallest machine chain should be used for forage areas less than 60 ha, whereas when the forage area exceeds 90 ha the largest machine chain should be chosen. In the 60-90 ha forage area range, there was little difference in costs between the S, M and L machine chains. For harvest with round bales only the size of the mower-conditioner varied between the machine chains and the largest machine chain had the lowest harvest costs for all forage areas. Machine cooperatives are a good way to lower harvesting costs since for smaller forage areas in particular, increased annual use of the machines decreases the machine costs and allows larger machines to be used to greater capacity. To avoid high timeliness costs it is important that cuts are performed at the optimal time.

In this report future annual emissions amounts of gaseous pollutants, particulate matter (PM10) and noise from the non-road mobile machinery sector in Sweden were estimated. The estimates over future emissions amounts were conducted for each year from 2006 to 2020. Special focus has been taken to the impact of European and national legislations, the age distribution of different types and sizes of machinery and measures to reduce the annual emissions. Besides different measures to reduce emissions, corresponding costs were also estimated. The study comprises fuel consumption and emissions of CO2, carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), particulate matter (PM), and noise from non-road mobile machinery equipped with diesel engines with a rated engine power of 37 to 560 kW. Non-road mobile machinery for example includes tractors, wheel loaders, excavators, articulate haulers, mobile cranes, combined harvesters, forestry machinery and trucks. The current report was a supplementary study to a report describing a methodology for estimating annual fuel consumption and emissions from the non-road mobile machinery sector in Sweden for year 2006. Inventory data of the year 2006 study was obtained from the Swedish machinery testing institute’s machinery inspection operation, statistics of sale returns from trade organisations and the Swedish motor-vehicle register. The number of machinery and annual fuel consumption and emissions amounts for year 2006 is presented in table S1. Besides estimates of annual fuel consumption and emissions amounts, emissions of noise was also derived both at a national level and for a specific construction site. For the case study the results showed that it was possible to reduce the average noise level with more than 3 dB(A) compared with the base scenario just by choosing the machinery fulfilling the strictest noise limits, i.e. Stage II which was mandatory for most machinery from 2006. Other measures simulated included various types of retrofit of noise reduction packages. The specific cost for the different measures to reduce average noise emissions from the specific construction site varied from 4 000 up to more than 500 000 SEK dB-1. For the estimate of future fuel consumption and emissions amounts various simulations were conducted, each with a different measure for reducing the annual amounts. Five main emission reduction measures or programs were studied: - Scrappage program - Alternative fuel program - Voluntary emission regulation program - Retrofit of aftertreatment program - Noise reduction program The impact on engine exhaust gas emissions and noise of the current European emission and noise regulations, Stage I to IV and Stage I to II for emissions and noise respectively were common for all simulations or programs. Besides the impact of European regulations, annual work was set to a fixed value for each type of machinery and year simulated, thus eliminating any potential changes of the state of the market. The result of the baseline scenario "Business as usual" (BAU), i.e. only taking account to the impact of European regulation, is presented in table S2 for four different years Both fuel consumption and emissions of CO2 remains fairly constant as an effect of the assumption that the annual work was set at a fixed value. However, emissions of especially NOx and PM showed a major reduction due to the tighter and tighter regulations. All programs simulated were able to reduce the emissions compared with the BAU scenario with exceptions for emissions of nitrogen oxides, which increased in some of the alternative fuel programs. Both the absolute reduction and cost varied significantly between and within the various programs. Reduction of NOx varied from an accumulated increase in emissions of 25 000 tonne to an accumulated reduction of 22 000 tonne for the studied period from 2006 to 2020. At the same time the accumulated cost for the programs varied from a few hundred million SEK to more than 60 000 million SEK. In table S3, specific reduction cost for each pollutant in SEK kg-1 for eight typical emission reduction programs are presented. The results showed that the most economically favourable alternative for reducing emissions from non-road mobile machinery was the voluntary emissions regulation program, i.e. early introduction of machinery fulfilling coming emission limits. Another important result was that the introduction of alternative fuels as a mean of emissions reduction was associated with rather high costs compared to the actual reduction in emissions. For emissions of nitrogen oxides the specific reduction cost varied from almost 100 SEK kg-1 up to a few hundreds of SEK kg-1 except for the alternative fuel programs, which resulted in a considerable higher cost.

The aim of the present work was to evaluate systems for making organic farms self-sufficient in bio-based fuels. The energy efficiency and environmental load for systems based on rape methyl ester (RME), ethanol and biogas produced by processing raw material from the farm in industrial-scale plants were evaluated using a life cycle perspective. Eventual constraints when implementing the systems in practice were also identified and the farmer’s costs for the systems estimated. The RME scenario showed some good characteristics; the energy efficiency and potential effects on global warming were favourable, the technology well known and no engine modifications were necessary. However, the high price of the organically produced rapeseed made the fuel expensive. The ethanol scenario provided fuel at a comparatively low cost, but the energy efficiency was low and existing engines would have to be modified. The biogas scenario was not as economically advantageous, due to high costs for storage and transport of the biogas and the extensive tractor modifications needed. The calculations further showed that systems based on so-called exchange of fuels, i.e. when the farm produces raw material for one type of biofuel, but instead uses another type of biofuel more suitable for its own tractors, were an economically favourable way of supplying the organic farms with ‘self-produced’ bio-based fuels. The exchange scenario based on delivery of organic wheat to a large-scale plant and use of RME at the farm was somewhat more expensive than scenarios based on production of biogas raw material at the farm. However, the wheat/RME system has the advantage of being possible to put into practice immediately, since industrial-scale wheat ethanol plants are in operation and RME fuel is available on the market.