Livsløpsanalyser (LCA)

Forskergrupper i NIBIO har de siste ti årene brukt livsløpsanalyser (Life Cycle Assessment = LCA) for å vurdere miljøeffekter av å produsere, distribuere, bruke og avfallshåndtere varer og tjenester med basis i biologiske ressurser. Dette både i egeninitiert forskning og i bestilte oppdrag fra næring og forvaltning.

KONTAKTPERSON
Medarbeidere
Pågående prosjekter der LCA brukes

  • Fôr og mat fra makroalger (PROMAC) (http://promac.no/)
  • Fôr og mat fra mikroalger (ALGAE TO FUTURE). Lenke til prosjektet nederst på siden.
  • Organiske ressurser i kretsløp -  en del av bioøkonomien (OKRETSLØP).
  • Utvikling av isolerende konstruksjonsmaterialer fra aggregater med biologisk opphav (ISOBIO) http://isobioproject.com/
  • Produktive og lønnsomme grovfôrbaserte husdyrproduksjoner (SusCatt). Lenke til prosjektet nederst på siden.
  • SolarFarm» En systemstudie av hvordan solstrøm produsert på gårdsnivå kan drive elektriske og delvis selvstyrte farkoster i et presisjonsjordbruk med reduserte utslipp av klimagasser. Lenke til prosjektet nederst på siden.

Publikasjoner

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Sammendrag

I dette studiet har vi ved hjelp av livsløpsanalyse (LCA) analysert miljøeffektane av å produsere norsk svinekjøtt. Utgangspunktet for analysa har vore eit fiktivt gardsbruk, plassert i Stange kommune, med kombinert svineproduksjon (både smågris-og slaktegrisproduksjon) og med kornproduksjon (bygg, vårkveite og havre) der gjødsla frå svinebesetninga blir utnytta. Som utgangspunkt analyserte vi eit tradisjonelt opplegg der grisane fekk kraftfôrblandingar tilpassa behovet som einaste fôr. Soya utgjorde 8% kraftfôrblandinga på råvektbasis. Vi analyserte svineproduksjonen under to ulike alternativ: a) At dei norske kornråvarene i kraftfôret var produsert på garden eller på ein tilsvarande gard, b) At dei norske kornråvarene i kraftfôret kom frå husdyrfrie gardar med mineralgjødsel som einaste gjødselslag. I tillegg analyserte vi på tilsvarande måte svineproduksjonen på garden i ein situajson der arealgrunnlaget blei utvida til også å omfatte eng, og der engavlinga blei brukt i ein bioraffineringsprosess til å produsere grassaft som proteinfôr til slaktegrisane i besetninga. Pressresten (pulp) blei selt som grovfôr til lokale storfeprodusentar. I tillegg til grassaft fekk slaktegrisane kraftfôr med redusert innhald av soya (6%) samanlikna med standardblandinga. Samla ga denne fôrrasjonen dekning av slaktegrisane sitt næringsbehov, slik at tilvekst og produksjonsresultat var det same i begge produksjonsopplegga.....

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Sammendrag

More than sixty environmental product declarations of insulation materials (glass wool, mineral wool, expanded polystyrene, extruded polystyrene, polyurethane, foam glass and cellulose) have been examined and the published information for global warming potential (GWP) and for embodied energy (EE) has been analysed and is presented. A peer-review literature survey of the data for GWP and EE associated with the different insulation products is also included. The data for GWP (kg carbon dioxide equivalents) and EE (megajoules) is reported in terms of product mass or as a functional unit (FU) (1 m2 of insulation with R = 1 m2 K/W). Data for some classes of insulation material (such as glass wool) exhibit a relatively narrow range of values when reported in terms of weight of product or as a functional unit. Other classes of insulation material exhibit much wider distributions of values (e.g., expanded polystyrene). When reported per weight of product, the hydrocarbon-based insulation materials exhibit higher GWP and EE values compared to inorganic or cellulosic equivalents. However, when compared on an FU basis this distinction is no longer apparent and some of the cellulosic based materials (obtained by refining of wood chips) show some of the highest EE values. The relationship between the EE and GWP per kg of insulation product has also been determined as being 15.8 MJ per kg CO2 equivalents.

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Reduced N-surpluses in dairy farming is a strategy to reduce the environmental pollution from this production. This study was designed to analyse the important variables influencing nitrogen (N) surplus per hectare and per unit of N in produce for dairy farms and dairy systems across 10 certified organic and 10 conventional commercial dairy farms in Møre og Romsdal County, Norway, between 2010 and 2012. The N-surplus per hectare was calculated as N-input (net N-purchase and inputs from biological N-fixation, atmospheric deposition and free rangeland) minus N in produce (sold milk and meat gain), and the N-surplus per unit of N-produce as net Ninput divided by N in produce. On average, the organic farms produced milk and meat with lower N-surplus per hectare (88 ± 25 kg N·ha−1) than did conventional farms (220 ± 56 kg N·ha−1). Also, the N-surplus per unit of N-produce was on average lower on organic than on conventional farms, 4.2 ± 1.2 kg N·kg N−1 and 6.3 ± 0.9 kg N·kg N−1, respectively. All farms included both fully-cultivated land and native grassland. Nsurplus was found to be higher on the fully cultivated land than on native grassland. N-fertilizers (43%) and concentrates (30%) accounted for most of the N input on conventional farms. On organic farms, biological Nfixation and concentrates contributed to 32% and 36% of the N-input (43 ± 18 N·kg N−1 and 48 ± 11 N·kg N−1), respectively. An increase in N-input per hectare increased the amount of N-produce in milk and meat per hectare, but, on average for all farms, only 11% of the N-input was utilised as N-output; however, the N-surplus per unit of N in produce (delivered milk and meat gain) was not correlated to total N-input. This surplus was calculated for the dairy system, which also included the N-surplus on the off-farm area. Only 16% and 18% of this surplus on conventional and organic farms, respectively, was attributed to surplus derived from off-farm production of purchased feed and animals. Since the dairy farm area of conventional and organic farms comprised 52% and 60% of the dairy system area, respectively, it is crucial to relate production not only to dairy farm area but also to the dairy system area. On conventional dairy farms, the N-surplus per unit of N in produce decreased with increasing milk yield per cow. Organic farms tended to have lower N-surpluses than conventional farms with no correlation between the milk yield and the N-surplus. For both dairy farm and dairy system area, N-surpluses increased with increasing use of fertilizer N per hectare, biological N-fixation, imported concentrates and roughages and decreased with higher production per area. This highlights the importance of good agronomy that well utilize available nitrogen.

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Increased nutrient cycling in the agri-food system is a way to achieve a healthier nutrient stewardship and more sustainable food production. In life cycle assessment (LCA) studies, use of recycled fertilizer products is often credited by the substitution method, which subtracts the environmental burdens associated with avoided production of mineral fertilizer from the system under study. The environmental benefits from avoided fertilizer production can make an important contribution to the results, but different calculation principles and often implicit assumptions are used to estimate the amount of avoided mineral fertilizer. This may hinder comparisons between studies. The present study therefore examines how the choice of substitution principles influences LCA results. Three different substitution principles, called one-to-one, maintenance, and adjusted maintenance, are identified, and we test the importance of these in a case study on cattle slurry management. We show that the inventory of avoided mineral fertilizer varies greatly when the different principles are applied, with strong influences on two-thirds of LCA impact categories. With the one-to-one principle, there is a risk of systematically over-estimating the environmental benefits from nutrient cycling. In a sensitivity analysis we show that the difference between the principles is closely related to the application rate and levels of residual nutrients in the soil. We recommend that LCA practitioners first and foremost state and justify the substitution method they use, in order to increase transparency and comparability with other studies. © 2017 Elsevier B.V. All rights reserved.

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Specialized agricultural production between regions has led to large regional differences in soil phosphorus (P) over time. Redistribution of surplus manure P from high livestock density regions to regions with arable farming can improve agricultural P use efficiency. In this paper, the central research question was whether more efficient P use through manure P redistribution comes at a price of increased environmental impacts when compared to a reference system. Secondly, we wanted to explore the influence on impacts of regions with different characteristics. For this purpose, a life cycle assessment was performed and two regions in Norway were used as a case study. Several technology options for redistribution were examined in a set of scenarios, including solid–liquid separation, with and without anaerobic digestion of manure before separation. The most promising scenario in terms of environmental impacts was anaerobic digestion with subsequent decanter centrifuge separation of the digestate. This scenario showed that redistribution can be done with net environmental impacts being similar to or lower than the reference situation, including transport. The findings emphasize the need to use explicit regional characteristics of the donor and recipient regions to study the impacts of geographical redistribution of surplus P in organic fertilizer residues.

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The aim of the study was to explore whether and how intensification would contribute to more environmentally friendly dairy production in Norway. Three typical farms were envisaged, representing intensive production strategies with regard to milk yield both per cow and per hectare in the three most important regions for dairy production in Norway. The scores on six impact categories for produced milk and meat were compared with corresponding scores obtained with a medium production intensity at a base case farm. Further, six scenario farms were derived from the base case. They were either intensified or made more extensive with regard to management practices that were likely to be varied and implemented under northern temperate conditions. The practices covered the proportion and composition of concentrates in animal diets and the production and feeding of forages with different energy concentration. Processes from cradle to farm gate were incorporated in the assessments, including on-farm activities, capital goods, machinery and production inputs. Compared to milk produced in a base case with an annual yield of 7250 kg energy corrected milk (ECM) per cow, milk from farms with yields of 9000 kg ECM or higher, scored better in terms of global warming potential (GWP). The milk from intensive farms scored more favourably also for terrestrial acidification (TA), fossil depletion (FD) and freshwater eutrophication (FE). However, this was not in all cases directly related to animal yield, but rather to lower burden from forage production. Production of high yields of energy-rich forage contributed substantially to the better scores on farms with higher-yielding animals. The ranking of farms according to score on agricultural land occupation (ALO) depended upon assumptions set for land use in the production of concentrate ingredients. When the Ecoinvent procedure of weighting according to the length of the cropping period was applied, milk and meat produced on diets with a high proportion of concentrates, scored better than milk and meat based on a diet dominated by forages. With regards to terrestrial ecotoxicity (TE), the score was mainly a function of the amount of concentrates fed per functional unit produced, and not of animal yield per se. Overall, the results indicated that an intensification of dairy production by means of higher yields per animal would contribute to more environment-friendly production. For GWP this was also the case when higher yields per head also resulted in higher milk yields and higher N inputs per area of land.

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Sammendrag

Due to the limited resources of fossil fuels and the need to mitigate climate change, energy utilisation for all human activity has to be improved. The objective of this study was to analyse the correlation between energy intensity on dairy farms and production mode, to examine the influence of machinery and buildings on energy intensity, and to find production related solutions for conventional and organic dairy farms to reduce energy intensity. Data from ten conventional and ten organic commercial dairy farms in Norway from 2010 to 2012 were used to calculate the amount of embodied energy as the sum of primary energy used for production of inputs from cradle-to-farm gates using a life cycle assessment (LCA) approach. Energy intensities of dairy farms were used to show the amount of embodied energy needed to produce the inputs per metabolizable energy in the output. Energy intensities allow to easily point out the contribution of different inputs. The results showed that organic farms produced milk and meat with lower energy intensities on average than the conventional ones. On conventional farms, the energy intensity on all inputs was 2.6 ± 0.4 (MJMJ?1) and on organic farms it was significantly lower at 2.1 ± 0.3 (MJ MJ?1). On conventional farms, machinery and buildings contributed 18% ± 4%, on organic farms 29% ± 4% to the overall energy use. The high relative contribution of machinery and buildings to the overall energy consumption underlines the importance of considering them when developing solutions to reduce energy consumption in dairy production. For conventional and organic dairy farms, different strategies are recommend to reduce the energy intensity on all inputs. Conventional farms can reduce energy intensity by reducing the tractor weight and on most of them, it should be possible to reduce the use of nitrogen fertilisers without reducing yields. On organic dairy farms, energy intensity can be reduced by reducing embodied energy in barns and increasing yields. The embodied energy in existing barns can be reduced by a higher milk production per cow and by a longer use of the barns than the estimated lifetime. In the long run, new barns should be built with a lower amount of embodied energy. The high variation of energy intensity on all inputs from 1.6 to 3.3 (MJ MJ?1) (corresponding to the energy use of 4.5e9.3 MJ kg-1 milk) found on the 20 farms shows a potential for producing milk and meat with lower energy intensity on many farms. Based on the results, separate recommendations were provided for conventional and organic farms for reducing energy intensity.

Sammendrag

To improve environmental sustainability it is important that all sectors in a society contribute to improving the utilization of inputs as energy and nutrients. In Norway, dairy farming contributes with an important share to the added value from the agricultural sector, although there is little information available about utilization of energy and nitrogen (N). Many results on sustainability have been published on dairy farming. However, due to Norway’s Nordic climatic conditions, mountainous and rugged topography and an agricultural policy that can design its own prices and subsidies, results from other countries are hardly representative for Norwegian conditions. To bridge this gap, the objective of this study was to analyse if the utilisation of nitrogen and energy in dairy farming in Norway can be improved to strengthen its environmental sustainability. Data were collected from 2010 to 2012 on 10 conventional and 10 organic farms in a region in central Norway with dairy farming as the main enterprise. The farms varied in area, number of dairy cows and milk yield. For nitrogen, a farm gate balance was applied and supplemented with nitrogen fixation by clover and atmospheric N-deposition. The total farm area was broken down into three categories: dairy farm area utilized directly by the farm, off-farm area needed to produce imported roughages and concentrates, and free rangeland that only can be used for grazing.

Sammendrag

I dette studiet analyserte vi miljøeffekter av å produsere erter og åkerbønner i et korndominert vekstskifte på en gård ved Oslofjorden ved hjelp av livsløpsanalyse (LCA). Miljøeffekter av høsthvetedyrking (samme gård) ble tatt med som referanse. Miljøeffektene ble uttrykt gjennom følgende ni miljøindikatorer; globalt oppvarmingspotensial, eutrofiering av ferskvann, eutrofiering av marine miljøer, økotoksisitet i ferskvann, terrestrisk forsuring, forbruk av fossil energi, human toksisitet, økotoksisitet i marine miljø og terrestrisk økotoksisitet. Systemgrensen ble definert til å være lik gårdens fysiske grense og analysen dekket alle de viktigste prosessene inkludert i omvandlingen fra råstoff til produkt leveringsklart ved gårdsgrinda («cradle to farmgate»). Studien omfattet også prosesser som ofte utelates i LCA-studier, slik som produksjon av maskiner, bygninger og produksjon og bruk av plantevernmidler, samt humusmineralisering og utslipp av NOx fra mineralgjødsel. Tidsperioden for analysen var ett fullt produksjonsår, og for alle data brukte vi gjennomsnittsverdier for tiåret 2001-2010. Funksjonell enhet var enten ett kilo lagringsklart produkt (85% tørrstoff) eller ett kilo protein. Når funksjonell enhet var per kg produkt ble det globale oppvarmingspotensialet for henholdsvis erter og åkerbønner 0,94 og 0,80 kg CO2-ekvivalenter, og dermed på nivå med det vi har funnet tidligere for norskprodusert korn. Med 1 kg protein som funksjonell enhet var tilsvarende verdier 5,0 og 3,1 kg CO2-ekvivalenter. Hvis dette proteinet i stedet skulle blitt produsert i form av melk eller kjøtt, ville oppvarmingspotensialet blitt vesentlig større. Basert på tall fra noen av våre tidligere studier med tilsvarende metodikk, kom vi fram til at oppvarmingspotensialet per kg protein er 9-15 ganger høyere for melk og 14-29 ganger høyere for kjøtt (fra melkeproduksjonen) enn tilsvarende for de to proteinvekstene analysert her. Når alle de ni miljøindikatorene ble sett under ett viste resultatene at proteinet i åkerbønner ble produsert med et gjennomgående lavere miljøforavtrykk enn tilsvarende i høsthvete. Erter var delvis bedre, delvis dårligere enn høsthveten. En gjennomgang av proteinvekstene og deres vekstpotensial i Norge viste at potensialet for erter og åkervekster ligger på omtrent 230 000 daa til sammen. Det må også nevnes at oljevekster representerer en potensielt stor proteinkilde, med en proteinkonsentrasjon i frøet på 20-25% og et potensielt dyrkingsareal på ca. 380 000 daa. Proteinet i oljevekster brukes i dag nærmest utelukkende til fôr. Den volummessig viktigste vekstgruppen i Norge for produksjon av protein nyttbart for mennesker er imidlertid korn, som har et proteininnhold på 11-15% og et potensielt dyrkbart areal på godt over 3,3 mill. daa. Lokalklima og vær utgjør den mest begrensende faktoren for produksjon av vegetabilsk protein her til lands i dag.

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Sammendrag

Embodied energy in barns is found to contribute to about 10–30% of total energy use on dairy farms. Nevertheless, research on sustainability of dairy farming has largely excluded consideration of embodied energy. The main objectives of this study were to apply an established model from the residential and commercial building sector and estimate the amount of embodied energy in the building envelopes on 20 dairy farms in Norway. Construction techniques varied across the buildings and our results showed that the variables which contributed most significantly to levels of embodied energy were the area per cow-place, use of concrete in walls and insulation in concrete walls. Our findings are in contrast to the assumption that buildings are similar and would show no significant differences. We conclude that the methodology is sufficiently flexible to accommodate different building design and use of materials, and allows for an efficient means of estimating embodied energy reducing the work compared to a mass material calculation. Choosing a design that requires less material or materials with a low amount of embodied energy, can significantly reduce the amount of embodied energy in buildings.