ONLINE RESOURCE 2

Waste and Biomass Valorisation_Hagman and Feiz_Advancing the circular economy through organic by-product valorisation—A multi-criteria assessment of a wheat-based biorefinery_ Linköping University_ linda.hagman@liu.se

ONLINE RESOURCE 2

1.

Quantitative assumptions

Table 1. The main quantitative assumptions for the studied by-product management alternatives (scenarios). Data is based on [1] or information received from involved actors if nothing else is stated.

By-product

management scenario Main assumptions Common assumptions

for all scenarios • The amount of stillage treated is assumed to be 200 000 tonnes with a total solids (TS) content of 7%. • Nordic electricity mix—GWP: 0.03 kg CO2-eq/MJ; Primary Energy Factor (PEF): 1.7 MJ/MJ

(1)_.

• Average heat from Swedish district heating GWP: 0.03 kg CO2-eq/MJ; PEF: 0.9 MJ/MJ heat1.

• Diesel—GWP: 2.94 kg CO2-eq/L; PEF: 1.2 MJ/MJ (1).

• Mineral fertilisers—Substitution is based on NPK content of biofertiliser. N fertiliser—GWP: 6.6 kg CO2-eq/kg N, PEF: 48 MJ/kg N (2).

Fodder • Each tonne of stillage replaces 28 kg soy feed and 42 kg barely feed per tonne of stillage (3)_.

• Commercial fodder, average values based on above feed combination—GWP: 662 kg CO2

-eq/kg TS feed; PEF: 5.5 MJ/kg TS (3)_;

• Stillage—Price as fodder: 60 SEK/tonne; • Transport distance: 50 km.

Fertiliser • Nutrient content of stillage: 3.3 kg N/tonne (0.7 kg NH4-N/tonne) and 0.4 kg P.

• Price of stillage as fertiliser: Negligible. • Transport: 20 km.

Incineration • Energy content of stillage (for incineration): 20.2 MJ/kg TS (based on LHV). • Price of heat: 300 SEK/MWh.

• Price of electricity: 650 SEK/MWh.

• Transport: Material is pumped to nearby incineration plant. Distant biogas for fuel • Biogas yield of stillage: 19.1 Nm3_{/tonne (687 MJ/tonne).}

• Digestion efficiency: 85% (of the yield is achieved).

• Flaring: 7% of the produced biogas (a relatively high and therefore conservative assumption). • Nutrient content of digested stillage: 3.3 kg N/tonne (2.3 kg NH4-N/tonne) and 0.4 kg P.

• Price of biogas: 15 SEK/Nm3

• Price of biofertiliser: Negligible.

• Transport: 120 km (stillage), 20 km (biofertiliser), 130 km (upgraded biogas, compressed). Local biogas for fuel • Same as “Distant biogas for fuel” scenario.

• Transport: 3 km (stillage), 20 km (biofertiliser), 130 km (upgraded biogas, compressed). Local biogas for heat

and power • Same as “Distant biogas for fuel” scenario, but instead of producing upgraded biogas, raw biogas is used to produce electricity and heat, where 43.3% of the energy content of the biogas is converted into electricity and 43.7% is converted into usable heat.

• Price for heat and electricity: Same as “Incineration” scenario.

• Transport: 3 km (stillage), national grid (electricity), local district heating network (heat), 20 km (biofertiliser).

1. PEFs and climate impacts for electicity, diesel and biogas are based on Gode et al. Miljöfaktaboken 2011-Uppskattade emissionsfaktorer för bränslen, el, värme och transporter. (2011) [2].

2. Börjesson, P., Lantz, M., Andersson, J., Björnsson, L., Möller, B.F., Fröberg, M., Hanarp, P., Hulteberg, C., Iverfeldt, E., Lundgren, J., Röj, A., Svensson, H., Zinn, E., 2016. Methane as Vehicle Fuel---A Well-to-Wheel Analysis (METDRIV) (No. f3 2016:06). f3. [3]

3. Tufvesson, L. & Lantz, M. Life cycle analysis of biogas from residues; Livscykelanalys av biogas från restprodukter. (2012) [4].

2.

Motivation of the article results

All six development scenarios are assessed according to the defined scales of the indicators found in Online resource 1. The motivations for the results are presented for each key area, divided into each indicator as a subsection.

Energy and environmental performance, nutrient and resource economy

Nutrient recirculation

Nutrient recirculation evaluates to what extent nutrients are recirculated in the studied systems. Good is received if 70–90% is recirculated. Fodder scenario recovers nutrients for the animals while Fertiliser scenario and the three Biogas scenarios all recover nutrients for fertilising resulting in Very Good. The exception is Incineration scenario, receiving Very Poor where the remaining nutrients in the ashes are not possible to recover yet as they are co-incinerated with waste.

Primary energy performance

Primary energy performance is a quantitative indicator that has been assessed based on the primary energy use corrected by the value of the final products to compensate for scenarios that generate higher value products; according to the following equation:

𝑃𝐸 𝑝𝑒𝑟𝑓𝑜𝑟𝑚𝑎𝑛𝑐𝑒 = 𝑃𝐸𝑆𝑐𝑒𝑛𝑎𝑟𝑖𝑜 𝑥 𝐾𝑣 − 𝑃𝐸𝑅𝑒𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑃𝐸𝑅𝑒𝑓𝑒𝑟𝑒𝑛𝑐𝑒

The valorisation coefficient (Kv) is the ratio of the value of the delivered products and services of the

by-product management scenario to the value of by-products and services of the reference case, i.e. Fodder (see Online resource 1 for more information). System expansion is used to calculate the net primary energy use (or savings) of the by-product management scenario (stillage as fodder replacing commercial fodder; biogas as fuel replacing diesel; biofertiliser replacing mineral fertiliser; electricity and heat from incineration or biogas plant replacing Swedish electricity mix and district heating). The score Good is obtained if the primary energy performance is 10–30% higher than that of the reference case, and Poor is obtained if it is 10–30% lower. In Table 1 the underlying data used for calculations are provided.

Table 2. Estimates of primary energy performance using system expansion. The values have been rounded. See Table 1 for underlying data.

Fodder Fertiliser

Incin-eration Distant Biogas for fuel

Local Biogas for fuel

Local biogas for heat and power Value of products from

treatment of one tonne stillage (SEK)

59 1 163 285 285 79

PE used/avoided for treatment of one tonne stillage (MJ)

-353 -231 434 -1275 -1353 -1377

Score REF VP VP VG VG VG

Fodder is the reference case and Fertiliser scenario receives Very Poor due to the low payment for the fertiliser and because the replaced fodder avoids more primary energy compared to avoided mineral fertiliser. Incineration requires extra heat (from other wastes) to evaporate all the water in the stillage which gives Very Poor energy efficiency even though electricity and heat are produced, and the economy is better compared to the reference case. Unlike all other scenarios (which are net producer of PE), we have used an inverse valorisation coefficient (1/kv) for the incineration to avoid penalising the incineration scenario

for being a net PE consumer, despite its positive outlook in terms of producing higher value products compared to the reference case. The three Biogas scenarios receive Very Good due to the improved PE performance and higher income (from the upgraded biogas, or heat and power) than the fodder in the reference case.

Climate change performance

Climate change performance is a quantitative indicator that has been assessed based on the life-cycle greenhouse gas (GHG) emissions corrected by the value of the final products to compensate for scenarios that generate higher value products (same as the primary energy performance) (Online resource 1). In the scenarios Fertiliser, Local Biogas for Fuel, Local Biogas for Heat, and Power and Distant Biogas for Fuel, the produced products (stillage or digestate as biofertiliser) replace mineral fertiliser. But, in Local Biogas for Fuel, and Distant Biogas for Fuel gasoline is also replaced (avoided), while in Local Biogas for Heat and Power Nordic electricity and district heating from the waste incineration is replaced (avoided). More detailed data can be found in Table 1. Greenhouse gas emissions from transportation and processes (such as methane slippage or energy use) are included, as well as N2O emissions from fields when

distributing biofertiliser and stillage as fertiliser.

Table 3. Estimates of climate change performance using system expansion. The values have been rounded. See Table 1 for specific data.

Fodder Fertiliser Incineration Distant Biogas for fuel

Local Biogas

for fuel Local biogas for heat and power Value of products from one tonne stillage (SEK) 60 1 162 285 285 79 GHG emissions emitted/avoided for treatment of one tonne of stillage (kg CO2 -eq) -46 -57 +25 - 93 -105 -65 Score REF VP VP VG VG VG

Fodder is the reference case against which other scenarios are compared. The Fertiliser scenario receives Very Poor due to the low payment for the fertiliser even though the GHG-emissions saving from replacing mineral fertilisers is higher than replacing fodder. Incineration requires extra heat (from other wastes) to evaporate all the water in the stillage resulting in positive greenhouse gas emissions giving the score Very Poor even though the economy is better compared to the reference case. Unlike all other scenarios (which are avoiding more GHG emissions compared to the reference), we have used an inverse valorisation coefficient (1/kv) for the incineration to avoid penalising the incineration scenario for being a net GHG

emitter, despite its positive outlook in terms of producing higher value products compared to the reference case. The three Biogas scenarios receive Very Good due to more GHG-emissions avoided and higher income (from the upgraded biogas, or heat and power) than the fodder in the reference case.

Local/regional environmental impacts

The local environment can be affected by the scenarios. This indicator shall therefore qualitatively evaluate if there are positive or negative effects. For example, Fodder and Fertiliser could improve biodiversity in the area if the animals are free-ranging and if fertiliser is used in organic farming. Fodder gets Good as the wet stillage reduces the demand on freshwater resources, while Fertiliser range between Poor to Fair as stillage may harm growing plants due to the low pH [5]. Biofertilisers from the three biogas scenarios are known to improve soil characteristics [6], and in the long run, those soils bind more carbon [7]. Worth considering are possible leakages leading to eutrophication from the biofertilisers [8]. Through interviews, we know that in the three biogas scenarios increased organic farming has occurred, which leads to better long-term health for the surrounding ecosystem [9]. All of the three biogas scenarios have received Good. Another aspect is that municipal vehicles have begun to run on biogas, which improves local air quality [10]. Incineration will not affect the local environment in a specific way, and receives Fair. None of the scenarios seem to have a clearly negative impact on the local environment. The certainty for all scenarios is

set to ** as there are uncertainties regarding how generalizable these possible effects can be, and we do not have strong proof that all these effects occur in the studied case. Nevertheless, these are the effects that are expected to occur for these types of scenarios.

Economic feasibility

Profitability or cost efficiency

The profitability and cost efficiency are Good if the scenario provide about 10–30% more income for the biorefinery compared to the reference scenario Fodder, and Poor if it gives losses of the same magnitude. The assessment has looked at the different potential direct income or costs for the biorefinery related to the different scenarios. Not all exact numbers can be presented due to confidentiality agreement but the relative differences are visualised in Hagman et al. [1]. Fodder is used as the reference case and is provided with a small income in the same size as the Local Biogas for Fuel scenario, while having transportation costs to handle, and both are therefore set to Fair. Fertiliser, Incineration and Distant Biogas for Fuel are associated with a large transportation cost for the biorefinery while Local Biogas for heat and power provides a smaller income (about 80% less than Fodder and Local Biogas for Fuel) as electricity in Sweden is cheaper than fuel. Therefore, all those alternatives are set to Very Poor.

Transportation efficiency

The transportation efficiency is estimated based on tonne.km and then compared to the reference case, which is Fodder, see Table 1 for data. The Fertiliser scenario reduces transportation with 60% resulting in Very Good (transportation is more than 30% less compared to the reference scenario). The stillage can be pumped to the incineration plant and thus require no transportation, resulting in Very Good. Local Biogas for Fuel, Local Biogas for heat and power reduce transportation by about 52–56% for these scenarios compared to the Fodder scenario and the score is Very Good. Distant Biogas for Fuel receives Very Poor, as the long transportation of stillage and including the distribution of biofertiliser and gas resulting in an increase of 180%.

Reduced load on waste-management system

The indicator "reduced load on waste management systems" is assessed in comparison to the reference case which is Fodder. Fodder does not have any impact on the waste management system, and neither do the Fertiliser or Biogas scenarios. But since Fodder is set as the reference no improvement is seen for the Fertiliser and Biogas scenarios and they score Fair. Incineration is a waste management treatment, and the load will increase more than 30% in this scenario, resulting in Very Poor.

Geographical and physical suitability

Geographical and physical suitability

Geographical and physical suitability refers to the suitability of the development sites for the scenarios. The site can interfere with protected areas, the distance between actors is long, or physical problems exist regarding the accessibility of resources. The biorefinery is situated in a central industrial area near the incineration plant. The local biogas plant is situated near the city landfill area. Both of these areas, therefore, are clear for not interfering with natural or urban values. Thus, the Fodder, Fertiliser, Local Biogas for Fuel and Local Biogas for heat and power scenarios are set to Good. Distant Biogas for Fuel gets Poor, due to the long transportation (more than 100 km) of the bulky stillage. A physical hinderance for Incineration is the possibility to handle large quantities of wet substrate, resulting in Poor. A portion of approximately 10% of the total could be handled by moisturising their other wastes according to the respondents, but the full amount of stillage is hard to incinerate.

Technical feasibility

Technological readiness

Technological readiness refers to the matureness of technologies used in the different scenarios. In Fodder and Fertiliser, there are no specific technologies needed more than stirred tanks at the farms as the stillage sediment and a need for solutions regarding the distribution of fertilisers on the field, the score is therefore Good. The three biogas scenarios have mature technology which is well established and tested, but the distribution of gas could improve in Local Biogas for Fuel and Distant Biogas for Fuel resulting in Good, while Local Biogas for heat and power achieves Very Good with mature technology and existing local grids. Another part of the biogas production is the treatment of digestate. Dewatering the digestate would decrease transportation need and provide farmers with more easily distributed fertiliser. Technologies for this are under development. Today farmers need equipment which can spread wet biofertiliser. When it comes to Incineration, the results are Very Poor. There are spray techniques for wet substrates which can be used in both fluidised bed incineration and grate furnace, but for the amounts required, it cannot be handled with today’s technique. There are also problems with stillage, as it is ashes and destroy equipment [5].

Infrastructural readiness

Infrastructural readiness refers to the existence of critical infrastructure required for operation or if the infrastructure is planned and included in economic estimations. Most of the infrastructure required, such as roads, electricity grid, and communication networks, is already in place for the scenarios Fodder, Fertiliser and Local Biogas for heat and power, resulting in Very Good. Local Biogas for heat and power needs a connection to the existing electricity grid, and according to interviews, the grids for electricity and heat are nearby the biogas plant and the solution should be easy. Fodder and Fertiliser receives Very Good score as they are mainly transportation based and do not need new infrastructure. What the scenarios demand is that new customers have assured that the roads can handle heavy trucks and have storage tanks available. Local Biogas for Fuel and Distant Biogas for Fuel receives Good as critical infrastructure is in place, but improvements could be made. For example, there could be pipelines between the biorefinery and the biogas plant for stillage transportation. Incineration lacks critical infrastructure and requires the installation of pipelines and a buffer tank between the biorefinery and the incineration plant, leading to a Fair to Poor result for Incineration, but the involved actors claimed it would not be a large investment. This is the reason certainty is set to ** as there are uncertainties in how this should be constructed and paid for.

Organisational feasibility

Actors readiness

The indicator actor’s readiness assesses available partners for the scenario, if they have the knowledge required for collaboration and if they agree to collaborate. Fodder and Fertiliser have agricultural customers who are easy to find due to the agricultural area around the biorefinery. The farmers who are relevant for the Fodder and Fertiliser are often wheat suppliers to the biorefinery. There is a risk of market saturation nearby, but it is assumed there are enough interested farmers in those estimations. Fodder receives Very Good, while Fertiliser gets Good due to some aversion towards stillage as fertilisers among farmers. Incineration has good connections with the biorefinery, as it delivers energy in the form of steam, electricity and heat, and further collaboration could be developed, and as a new contact person regarding stillage treatment will be needed, Incineration receives Good. Local Biogas for Fuel and Local Biogas for heat and power have good connections between the biogas plant and the biorefinery resulting in Very Good. Distant Biogas for Fuel is situated further away, and it can, therefore, be harder to establish collaboration and trust, as it is hard to know potential development. Thus this scenario receives Fair to Good and the interval indicates uncertainties in the results which is also why it was assigned with the certainty of **.

Public acceptance and institutional feasibility

Public acceptance

Public acceptance and local opinion can be important whether a scenario is realisable or not. Fertiliser, Local Biogas for Fuel, Local Biogas for heat and power and Distant Biogas for Fuel are all considered Fair, as some opinion regarding smell from the biogas plants and the distribution of fertiliser can disturb the neighbours, although biofertiliser has less odour after treatment compared to manure as fertiliser [8]. Regarding the biogas scenarios, there is a "not in my backyard" sentiment [11]. Residents may be positive to a biogas plant, but do not want it nearby their homes. That is why the biogas scenarios receives ** for the certainty of assessment as the outcome of this indicator is case specific and difficult to measure. Nevertheless, the responses we have, suggested that it is Fair. The incineration plant has seen some complaints regarding its regular activities, but for this specific scenario no opinion is noted, as the stillage is transported in closed pipelines which are not disturbing the general public, and therefore received Very Good. Fodder is considered Good, where no major arguments are mentioned against it except the number of transports, which is a problem in several of the scenarios.

Institutional support and efficient administration

Institutional support and administration refer to subsidies, taxes or time-consuming administration required for the activity performed or products produced. In Sweden, where this study takes place, there are several laws regarding use of waste or by-products which demand some administration for the biorefinery. The fodder products are controlled by Jordbruksverket and the fertiliser by the KRAV organisation. Fodder and Fertiliser get Fair, as the scenarios require specific administration and are neither taxed extra nor receive subsidies. The other scenarios require some kind of permit for their activities. The permits control what materials are allowed in the production for both the incineration plant and the biogas plants. This means Incineration ranges from Poor to Fair, depending on the possibility to receive the permit. The biogas plants require permits, but they also have a tax exemption until 2030 [12], and the biofertilisers are controlled by the KRAV organisation. As some support exists for the biogas producers, Good is received in all three biogas scenarios. The certainty of this indicator is set to ** mainly due to the uncertainties in forthcoming legislation although the situation today assessed in the workshops indicate the given scores.

Planning horizon and clarity of business implications

The planning horizon and business implications refer to long-term stability and clarity of future conditions. The planning horizon is relatively short-term in the Fodder and Fertiliser scenarios, and one-year contracts are signed. The future conditions are affected if the biorefinery starts to dewater the stillage, which requires the customers to recalculate dosages and in Fertiliser even change the spreading technique, and therefore result in Fair for this indicator. Incineration is Fair reaching to Good as substrates may be needed for a long time, but the problem is whether stillage will be allowed to be incinerated, and the business implication is the problem here. The three first scenarios have a lowered certainty score to ** as it is somewhat unclear what will happen depending on different future pathways. Local Biogas for Fuel, Distant Biogas for Fuel and Local Biogas for heat and power have contracts longer than two years where deliveries and payments are regulated. These scenarios have environmental permits and customer contracts which show continuing businesses which is Very Good for the scenarios.

Market accessibility and control

This key area assesses access and control regarding supplies, intermediate flows and markets.

Upstream accessibility and control

The upstream control of raw material supply is the same for all scenarios as the raw material, wheat, is the common denominator to the biorefinery. The control of the supply is assumed to be Very Good, as the biorefinery has the possibility for long-term contracts and control of the upstream wheat production. The delivering farmers belong to the same cooperative as the biorefinery. The biorefinery mainly sets requirements for quality but does not control the amount of wheat produced.

Downstream accessibility and control

Handling of the final products to end customers is assessed in the indicator downstream accessibility and control. Agricultural areas are large around the studied case and several animal farms are situated there. The Fodder and Fertiliser scenarios therefore have a steady market but according to the workshop with the biorefinery, they have short-term contracts with the customer farmers, which are renewed yearly. If one farmer pulls out, it is easy to find a replacement, which results in Good for Fodder as this secures the market for at least five years forward which is the demand for the score Good. Larger amount of stillage to distribute could lead to difficulties in finding fodder customers. Fertiliser score Fair, as customers might find better fertilisers elsewhere and the market is more unstable, the stillage as fertiliser does not have the best reputation. The downstream control for Incineration and Local Biogas for heat and power looks similar. The market for heat and power lies steady, and the products are expected to be needed in the future, which is Very Good. The market for biogas as fuel is not as stable and depending on subsidies and the general societal debate the demand varies, but an established and open market exists in Sweden. The consumption of biogas for fuel is also increasing every year and has almost doubled since 2015 [13]. There is also an approved tax exemption for biogas as fuel for 10 more years [14]. But it is growing from a small number and of course there are risk of competition between actors. The downstream control for Local Biogas for Fuel and Distant Biogas for Fuel are therefore Good. These two scenarios have also received ** certainty stars due to some uncertainties in how the market will look.

Sidestream accessibility and control

This indicator refers to the streams between the biorefinery and facility which in turn produces new products/services which will be sold to end-users. Therefore, the indicator is only applicable to Incineration and the Biogas scenarios. Intermediate supply between the actors can be expected in a timely manner, and Incineration and all three biogas scenarios are considered Good. Actors in the interviews see no issues regarding this as agreements are established regarding deliveries.

Risk avoidance

Long-term risk-avoidance

The long-term risk indicator tries to identify whether there are potential future developments that may endanger the continuity of the studied system. The Fodder scenario is set to Fair as there is a possible risk that the by-product used as fodder will decrease in value if the biorefinery start to produce new high-value components or if the demand for fodder is reduced in the future. Fertiliser scenario is also Fair as there are issues connected to the use of stillage as fertiliser. Incineration is set to Poor as the long-term risk could be altered regulations or control means regarding the incineration of waste. If organic waste amounts are banned, this scenario will not be sustainable. There is an unknown risk of the wear in the incineration plant when incinerating stillage as well. The Distant Biogas for Fuel scenario receives Fair as the connections with a distant plant might not be as stable as a local plant. There are possibilities they will accept more local substrates if they find some. The two Local Biogas scenarios receives Good as there are no obvious long-term risks. If the carbon content is reduced in the stillage it may lead to lower methane production but on overall the risks seem low for the future of the biogas production scenarios. The fluctuations in the market and new regulations might affect all of the scenarios. The uncertainty is high on this indicator varying between * and ** as it is hard to predict the future but these results indicate a direction.

Biocascading

The biocascading indicator is situated under the risk avoidance key area as it has the potential of reducing long-term risks and making the biorefinery more resilient when several markets are targeted. Biocascading means that a variety of high-valued products are produced, but there is also the extraction of value from lower-quality streams. When looking into each scenario, some alternatives create higher value and more diverse product portfolio than others from the by-product stillage. Fodder scenario (reference) is seen as Very good as the stillage can be used as energy and nutrients for animals, while still receiving nutrients for fertilising in a later stage. The Fertiliser scenario only contributes with a low value fertilising option and is

therefore set to Fair. Incineration scenario which generates heat and power receives Poor due to limited upgrading of the material (e.g. nutrients are lost). The two biogas for fuel scenarios receive Very Good due to the relative high value of fuels and recovery of nutrients, while Local Biogas for heat and power scores Good as heat and power is not seen as high valued product as vehicle fuel in Sweden.

References

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2. Gode, J., Martinsson, F., Hagberg, L., Öman, A., Höglund, J.: Miljöfaktaboken 2011-Uppskattade emissionsfaktorer för bränslen, el, värme och transporter. (2011)

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https://www.britannica.com/topic/Not-in-My-Backyard-Phenomenon

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https://ec.europa.eu/info/news/state-aid-commission-approves-prolongation-tax-exemption-non-food-based-biogas-and-bio-propane-used-heating-or-motor-fuel-sweden-2020-jun-29_en

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