(Related to Chapter 20 – better transport) – In several cities Canadian waste trucks are powered by purified and compressed biogas (compressed natural gas = CNG) that is created from organic waste collected by the truck [6]. In this way a “circle” is created (a waste truck can drive on the gas that is created from the waste it collects). This circle could possibly also be implemented in the Netherlands, although Dutch households do not separate biodegradable waste very well. in 2013 on average 38% of the Dutch solid (household)waste still consisted of biodegradable waste [7]. If this amount was separated by households, lots of energy could be won. Leading to the question:

1. Question: How many garbage collection trucks could drive on biogas, derived from separated biodegradable solid household waste in the city of Amsterdam, and if there is a surplus in fuel, how many additional personal cars can drive on the biogas?

2. Final answer: Unsorted solid waste still contains 38% biodegradable waste. For solely the city of Amsterdam about 110 waste trucks could drive on this waste, enough for collecting waste for the whole city, plus for the driving of about 1,000 typical cars.

3. Procedure used to obtain your answer

In 2013 the city of Amsterdam generated about 423 kg waste per citizen per year [8]. In 2013 Amsterdam had 799,442 citizens [9]. In 2013 38% of the solid household waste in the Netherlands consisted of biodegradable waste, in Dutch called ‘gft-afval’ [7]. The percentage of biodegradable waste is not known in Amsterdam’s waste. Given the small amount of biodegradable waste collection bins in Amsterdam, it is assumed that even less citizens of Amsterdam separate their biodegradable waste. That is why the assumed percentage of solid household waste that consists of biodegradable waste is about 50% for Amsterdam. The city of Amsterdam does currently not separate biodegradable waste from the solid house hold waste.

That leads to an amount of organic biodegradable waste Amsterdam of 0.5 * 0.423 * 799442 = 169,081 metric tons per year.

Basic research on biogas from biodegradable household solid waste

When we look at the organic waste processing facility of Dutch company Orgaworld in Lelystad, this generates 100 m³ biogas per metric ton of organic waste. Another research confirms that for a current plant a tonne of biogas gives at minimum about 100 m³ biogas per metric ton organic waste [10].

Biogas is a mixture of 55%-60% methane (CH4), 40%-45% carbon dioxide (CO2) and some small amounts of other gases [10]. A compressed natural gas (CNG) fuel requires at least 89.14% methane [11]. Upgrading to vehicle fuel biomethane (BioCNG) and pressure standards (3600 PSI), the compression costs are 3% of the energy content of the upgraded biogas, as calculated by a Canadian biogas engineering firm, co-funded by the province of British-Columbia [12]. It is assumed that all 60% methane is filtered when upgrading the biogas to an 89.14% BioCNG fuel. So when upgrading 100m³ biogas, 67m³ (=60/0.8914) BioCNG is received.

The production cost of the BioCNG would break down to Canadian Dollar (CAD) 7.72/GJ for the biogas and CAD 6.76/GJ for the upgrading [12]. Although these are Canadian values it gives a sense that the upgrading costs from biogas to biomethane are substantial. A reason for upgrading is that you have a higher energetic gas that you can store for vehicles or deliver to the gas network. All gas volumes in this assignment are given in normal cubic meter (so m³ = Nm³).

To cross-reference these results with existing and planned plants, there are several biogas installations in the Netherlands, as described in table 1.

 

Installation	Biodegradable waste /year	Energy output/ year
Orgaworld Lelystad Biocel [13]	30,000 tons	3 million cubic meters biogas (4.2 GWh)
Orgaworld Surrey (planned), Canada [14]	80,000 tons plus 25,000 tons industrial waste	3 million cubic meters biogas
Uppsala Biogas, Sweden [15]	23,000 tons food waste plus 4,000 tons slaughter waste	4.6 million cubic meters biogas

Table 1: Several biogas project in and outside the Netherlands for giving a feeling about input waste capacities and output energy capacity.. Biogas in this table means a gas that consists of more than 55% methane. It is noteworthy that the Uppsala Biogas has the highest output yield. They are using a different anaerobic digestion method, namely a wet digestion method, whereas the Orgaworld biogas installations use a dry digestion method. The investment data of the plant of Orgaworld were obtained via Business in Vancouver and were CAD 68 million [16] and confirmed by a spokesmen of Orgaworld. Although the newer plants have similar biogas outputs, the newer plants have a larger compost and rest sources output. These residuals like compost are not taken into account since they are not relevant for energy purposes in this calculation.

Amsterdam’s biodegradable-waste-created CNG leads to a ceiled biomethane output of about 10 million m³ BioCNG, including a 80% well-to-pump [17] efficiency (152,173 metric ton biowaste * 67 m³ BioCNG/metric ton biowaste * 0.8 * 0.97 is in the order of magnitude of 10 million m³).

Madrid uses a total of 445 waste trucks to collect their solid household [18]. These 445 Iveco CNG refuse/waste trucks are fuelled by 10 million m³ BioCNG [19].

Amsterdam has no numbers about the amount of waste vehicles that it is using and what routes they are driving. That is why the amount of trucks needed to collect Madrid’s garbage is scaled back to the size of Amsterdam (in terms of population). The population of Amsterdam is about 4 times smaller than Madrid [20] and therefore the city of Amsterdam would need about 110 garbage trucks to collect waste.

Based on 110 garbage truck, this would lead to extra 7.5 million m³ pump-available BioCNG to fuel regular vehicles.

As MacKay (2008) estimates, a typical car (50km/day) uses 40kWh/d = 14600 kWh/y. The caloric value of methane is about 38 MJ/m³ [21], the 90% methane content in CNG needs to be taken into account. Taking into account the CNG tank-to-wheel efficiency of about 20% [17], leads to a remainder potential of: 7.5 million m³ biomethane * 0.2 * 38 * 0.9 = 51.3 TJ = 14.25 GWh. That is enough for about 1,000 typical cars.

4. Parameters used and describe for each parameter how it was found

• Related biogas plants for giving a feeling of normal energy outputs: [13], [14] and [15]
• Amsterdam amount of waste per citizen in 2013: 423 kg per year [8]
• Amsterdam population in 2013: 799,442 citizens [9]
• Percentage of biodegradable waste still found in Dutch rest waste: 38% [7]
• Metric tonne biodegradable waste, biogas yield: minimum 100 m³ per metric ton waste [10] and [13]
• CNG well-to-wheel efficiency: about 15% (Curran et al., 2014)
• CNG well-to-pump efficiency: about 80% (Curran et al., 2014)
• CNG tank-to-wheel efficiency: about 20% (Curran et al., 2014)
• CNG methane (CH4) percentage required for CNG driving: 89.14% [11]
• CNG purification energy and financial cost: 3% of the upgraded biogas energy content and $0.58/GJ [12].
• amount of Iveco waste trucks than can drive on 10 million m³ CNG: 445 [18]
• Madrid population ratio compared to Amsterdam: 4 times larger [20]
• Energy usage of an average person wagon: 40 kWh/day (MacKay, 2008)
• Production cost of BioCNG in Canada: Canadian Dollar (CAD) 7.72/GJ for the biogas and CAD 6.76/GJ for the upgrading. Although it are no Dutch values, it gives a feeling for the percentage of cost for upgrading biogas to BioCNG [12].

5. Discussion, including results from other sources or other estimates

Amsterdam is used in this question, since it is a city with a big waste truck fleet and a city that wants to reduce CO₂ emissions by 40% by 2025, compared to 1990 [22]. Biogas through anaerobic digestion has been evaluated as one of the most energy-efficient and environmentally beneficial technology for bioenergy production [23] and will help achieving these reduction goals. It is not known what the exact biodegradable waste percentage is in Amsterdam, that is why the Dutch percentage of biodegradable waste is taken into account. It is assumed that this amount is a bit higher for Amsterdam households than for Dutch households, since Amsterdam has a smaller amount of biodegradable waste collection bins, than other cities that provide bins with built-in biodegradable waste compartments. Further, the amount of 100 m³ biogas with about 55% methane content per ton biodegradable waste as estimated by Orgaworld is a bit lower than values of several crops [24] (e.g. wheat grain can generate a lot more than 100 m³/t). Although, because of the blend of several crops and less energetic waste, the estimated amount is a bit lower, so an estimate of 100m³ biogas per ton waste (Orgaworld, n.d.) seems reasonable. Plus, by using the minimum possible yield, the risk of overestimating yield numbers is diminished.

Cost aspect: Although there seems to be opportunity for converting biodegradable waste to biomethane, it has high investment costs. Another barrier is the low natural gas and oil price (RVO, Hugo Schotman, 2015), although these prices are higher in the Netherlands than in Canada where a waste loop concept is already viable. Subsidies may be necessary though and for example a CO₂-tax on regular gas may be an incentive for producing biomethane (Schotman, 2015). Given the environmentally friendliness of biomethane and the CO₂-goals cities like Amsterdam have, such a tax may be an interesting incentive. Another ‘cost’-aspect is the aspect of pickup. This may lead to a diversification of the waste fleet, requiring investments in different waste trucks, since separated biodegradable waste has to be collected separately from the normal solid waste.

In order to make sure if the case is possible and economically viable I asked a spokeswoman of DMT (a biogas installation company) if the case of Amsterdam as described above is possible. Her response can be found in Appendix A and she confirms that the case might be possible. Although, in a biogas installation other sources as sewage sludge may be needed to have enough energy for creating enough biogas to fuel the waste truck fleet. There are already other municipalities in the Netherlands where waste trucks drive on biomethane received from biodegradable waste [25].

Amsterdam has no numbers about the amount of waste vehicles that it is using and what routes they are travelling. Whereas Madrid concrete describes how much biomethane is needed to power its entire waste truck fleet, as given by the Natural & Bio Gas Vehicle Association Europe (2009). That is why these numbers are scaled to the size of Amsterdam. Feature research might take concrete numbers of Amsterdam into account, an attempt to contact the statistics department of Amsterdam has been done, but no response with relevant numbers has been received.

Finally, MacKay (2008) estimates that a typical car driver uses 40 kWh/day. He does not distinguish between diesel and petrol, because they have almost similar calorific values (about 10% difference). The calorific values of methane compared to petrol per kg have also about 10% difference. Because the final remainder of cars is rounded to 1000, a 10% differences has no impact on the remainder cars the could drive on the biofuel.

6. References

[6]	Canadian Biogas Association, “Closing the loop,” June 2015. [Online]. Available: http://www.biogasassociation.ca/bioExp/images/uploads/documents/2015/close_the_loop/RNG_Close_the_Loop_Primer_Web.pdf“`. [Accessed 11 February 2016].
[7]	Rijkswaterstaat, “Samenstelling van het huishoudelijk restafval, sorteeranalyses 2014 – Gemiddelde driejaarlijkse samenstelling 2013,” November 2015. [Online]. Available: http://www.rwsleefomgeving.nl/onderwerpen/afval/publicaties/downloads/samenstelling-4/. [Accessed 11 February 2016].
[8]	Centraal Bureau voor de Statistiek, “Huishoudelijk afval per gemeente per inwoner,” 12 February 2016. [Online]. Available: http://www.cbs.nl/nl-NL/menu/themas/natuur-milieu/cijfers/afval/gemeentelijk-afval-per-inwoner-sl.htm. [Accessed 12 February 2016].
[9]	Gemeente Amsterdam, “Amsterdam in cijfers 2015,” 2015. [Online]. Available: https://www.ois.amsterdam.nl/assets/pdfs/2015%20jaarboek%20amsterdam%20in%20cijfers.pdf. [Accessed 11 February 2016].
[10]	Canadian Biogas Association, “Farm to Fuel Developers’ Guide to Biomethane,” 2012. [Online]. Available: http://biogasassociation.ca/bioExp/images/uploads/documents/2012/reports/Developers_Guide_to_Biomethane.pdf. [Accessed 11 January 2016].
[11]	K. Subramaniana, V. C. Mathada, V. Vijayb and P. Subbaraoc, “Comparative evaluation of emission and fuel economy of an automotive spark ignition vehicle fuelled with methane enriched biogas and CNG using chassis dynamometer,” Applied Energy, pp. 17-29, 2013.
[12]	Electrigaz Technologies Inc., “Feasibility Study – Biogas upgrading and grid injection in the Fraser Valley, British Columbia,” 2008. [Online]. Available: http://www.lifesciencesbc.ca/files/PDF/feasibility_study_biogas.pdf. [Accessed 12 February 2016].
[13]	Orgaworld, “Lelystad: Biocel anaerobic digestion and composting plant,” [Online]. Available: http://www.orgaworld.com/more-about-our-business/our-locations/lelystad-biocel. [Accessed 11 February 2016].
[14]	P. Oostelbos, in Biogas Association Canada – Closing the Loop, Abbotsford, 2016.
[15]	G. Rogstrand, “Municipal Biogas Production in Sweden,” in Canadian Biogas Association – Closing the loop, Abbotsford, 2016.
[16]	A. Reid, “Surrey breaks ground on biofuel processing facility,” 2 March 2015. [Online]. Available: https://www.biv.com/article/2015/3/surrey-breaks-ground-biofuel-processing-facility/. [Accessed 13 February 2016].
[17]	S. J. Curran, R. M. Wagner, R. L. Graves, M. Keller and J. B. J. Green, “Well-to-wheel analysis of direct and indirect use of natural gas in passenger vehicles,” Energy, pp. 194-203, 2014.
[18]	NGVA Europe, “Case Study. February 2009 1 CNG trucks in urban garbage collection. The successful case of the FCC fleet in Madrid,” February 2009. [Online]. Available: http://www.marcogaz.org/egatec2011/PS2/PS2I_Lage_egatec2011.pdf. [Accessed 16 February 2016].
[19]	NGVA Europe, “Madrid’s fleet operators heavily rely on heavy-duty NGVs,” 27 March 2014. [Online]. Available: http://www.ngva.eu/madrids-fleet-operators-heavily-rely-on-heavy-duty-ngvs.
[20]	United Nations Statistics Division, “City population by sex, city and city type,” 2014. [Online]. Available: http://data.un.org/Data.aspx?d=POP&f=tableCode%3A240#POP. [Accessed 13 February 2016].
[21]	M. A. Laughton and D. Warne, “Electrical Engineer’s Reference Book,” in Electrical Engineer’s Reference Book, Oxford, Elsevier Science, 2003, p. 27/14.
[22]	Gemeente Amsterdam, “Amsterdam: a different energy – 2040 Energy Strategy,” February 2010. [Online]. Available: https://www.amsterdam.nl/gemeente/organisatie/ruimte-economie/ruimte-duurzaamheid/ruimte-duurzaamheid/making-amsterdam/publications/sustainability-0/2040_energy_strategy_0/. [Accessed 14 February 2016].
[23]	H. Fehrenbach, J. Giegrich, G. Reinhardt, U. Sayer, M. Gretz, K. Lanje and J. Schmitz, “Kriterien einer nachhaltigen Bioenergienutzung im globalen Maßstab,” UBA-Forschungsbericht 206, p. 41 – 11, 2008.
[24]	P. Weiland, “Biogas production: current state and perspectives,” Appl Microbiol Biotechnol, pp. 849-860, 2010.
[25]	TankPro, “Vuilniswagens gaan rijden op bananenschillen,” 18 November 2011. [Online]. Available: http://www.tankpro.nl/brandstof/2011/11/18/vuilniswagens-haarlemmermeer-gaan-rijden-op-bananenschillen/. [Accessed 13 February 2016].
[26]	U.S. Department of Energy, “Case Study – Compressed Natural Gas Refuse Fleets,” 2014. [Online]. Available: http://www.afdc.energy.gov/uploads/publication/casestudy_cng_refuse_feb2014.pdf. [Accessed 13 February 2016].
[27]	D. J. MacKay, “Sustainable Energy – Without the hot air,” Cambridge, UIT, 2008, p. 29.

7. Reliability of sources

This question involves lots of statistical data, scientific data, and other numbers. For statistical data, official statistical data was attempted to use as much as possible. These official sources include data from municipalities, national statistical data, and data from more international sources, like the United Nations. Since the question is mostly on a municipality-level, the data of municipalities had priority. If no data was available, data on a higher level (national and international) was used. For biogas characteristics it was tried to use as much scientific sources with more than 10 citations and published in a related and in a renowned journal. If that was not possible, related biogas association numbers were used. And if that was not possible, related contacts were personally contacted to get the right numbers and the right vision on the feasibility of this case. Only in a small amount of cases, if these data were not found, other sources like news and company sites were used. These sites were only used for exemplary data and not for critical data like the well-to-wheel efficiency of a CNG vehicle.