Annex I: LCA method in waste management

Life cycle assessment (LCA) is a methodology that seeks to identify the environmental impacts related to a product, service or system from a holistic standpoint that includes all known potential environ-mental impacts and follows the product, service or system from ”cradle to grave”. The life cycle in-cludes all known processes in the stages of extraction of raw materials, production, use and disposal.

The LCA method is standardized in ISO 14040/44. The LCA in waste management is based on this standard with certain amendments.

13.1.1 System boundaries and system comparison

The LCA method in waste management is focused on the waste sector. All waste management activi-ties – both direct emissions as well as potentially avoided emissions through substitution of primary products and energy – are included. All emissions from waste treatment are related to the waste amount considered (e.g. landfilling 100 year time horizon). The results represent mitigation potentials offering decision-making aid to politic, public authorities and industry.

Figure 41: left: Flow chart of a waste management system; right: System boundary and comparison rules in LCA visualized

To assess the waste sector the boundaries of the “cradle-to-grave” system begin with the waste (“pre-vious life” excluded) and end with the final purpose of waste treatment (secondary product, energy, and disposal). The benefits of compared systems (status quo and optimization scenarios) must be equal (Figure 41). Typically, this is realized by credits for co-benefits like secondary products and en-ergy generated. These credits are calculated as negative values and represent mitigation potentials be-cause it cannot be proofed that the assumed substitution of primary products or energy really takes place. In general, LCA practitioners should use the most likely substitution process. Nevertheless, for example in case of recycling the technical and not the market substitution potential shall be consid-ered. Which means 100% substitution is credited for secondary products as otherwise more recycling – and thus a lesser market substitution potential – would lead to lower GHG mitigation.

13.1.2 Other methodological agreements and data used

In the following relevant methodological agreements are listed and explained briefly. Comprehensive descriptions are to be found in previous studies (Dehoust et al. 2010, Vogt et al. 2015).

- Crediting for energy produced is performed using the average approach (grid electricity); in previous studies the marginal approach was used which assumes that ‘additionally’ produced

91 energy from waste generally substitutes fossil fuel. However, especially for comparison with mid- or long-term optimization scenarios the marginal approach tends to overestimate the GHG saving potential considering the climate change goals and energy transition. The emission factors equally used in this study for energy demand and credits are:

o emission factor for electricity generation in India: 928 g CO^R2^Req/kWh, o emission factor for heat generation: 334 g CO^R2^Req/kWh.

- In optimization scenarios no changes are made to emission factors for energy supply, neither for demand nor for credits, to ensure that differences by comparison with the status quo are the result of changes in waste management and not in the energy sector.

- Possible carbon sinks are not considered in the GHG scenarios for the 3 cities. Usually the car-bon sink – where it is quantifiable – is stated only in sensitivity analysis or reported for infor-mation only due to considerable uncertainties attached to the long-term storage of biogenic carbon. In this study the data for the 3 cities itself are associated with high uncertainties.

Therefore, the carbon sink is not addressed.

- Recycling is calculated using the harmonized emission factors provided in Vogt et al. (2015) as no national or regional data is available.

- Composting and anaerobic digestion are calculated using emission factors derived from meas-urements in Germany.

- Also due to the lack of regional or national data, landfilling is calculated using IPCC’s default values (IPCC 2006):

o DOCf = 50% (average value for all waste that may partly contain lignin) o Methane content = 50 Vol%

o Methane correction factor (MCF):

managed disposal sites – anaerobic = 1

unmanaged disposal sites – deep (> 5 m waste) and/or high water level = 0,8 unmanaged disposal sites – shallow (< 5 m waste) = 0,4

uncategorized disposal sites = 0,6

o Oxidation factor (OX):

default value = 0%

covered (e.g. soil, compost), well-managed landfill site^P18F19P = 10%

o Gas collection efficiency:

default value = 0%, if no data are available

default value = 20%, if estimated based on the installed gas collection system - Fossil and regenerative carbon content as well as heating value of the waste generated are

cal-culated based on the waste composition; the standard parameters used are shown in Table 13.

The values for organics, paper, plastics and textiles are derived from analysis results in (Weichgrebe et al. 2016) for the West Zone in Bangalore and are used for all 3 cities as no other data is available for India. The value for “others” is taken from (Dehoust et al. 2010) for Germany and the EU. Glass, inert and metals neither contain carbon nor contribute to energy generation.

19 Default for OX according to IPCC is 0%; the value of 10% is justified for covered, well-managed landfills.

92 Table 13: Standard parameters for waste fractions

total C share regenerativ C heating value

% by mass % total C kJ/kg

Organics 21 100 4779

Paper 25 100 9123

Plastics 50 0 23525

Textiles 31 56 14066

Glass 0 0 0

Inert 0 0 0

Metal 0 0 0

Others 21 53 7800

13.1.3 Impact assessment of global warming potential

Impacts on climate change (greenhouse effect, global warming) through different climate agents are mainly assessed using the aggregation method developed by the Intergovernmental Panel on Climate Change (IPCC). The IPCC provides indicators – the Global Warming Potentials (GWPs) – for climate gases for a 20-, 100- and 500-year time horizon. The GWPs for the 100-year time horizon are used in this study. The 100-year time horizon is nearest to the approximate lifetime of CO^R2^R in the atmosphere, and thus represents best the overall impact of CO^R2^R, which are responsible for 55-60% of anthropo-genic radiative forcing according to IGSD (2013). In addition, the GWP100 is used to calculate the na-tional emission inventories in compliance with the Kyoto Protocol. Table 14 shows the most recent GWP100 values of IPCC’s 5^PthP assessment report (IPCC 2013) which are used in this study. For compari-son also the GWP100 values from IPCC (1995) are presented which were first used for national report-ing under the Kyoto Protocol.

Table 14: Global warming potential for the 100-year time horizon of the most important green-house gases

Greenhouse gas CO^R2^R-equivalent value (GWP100)

[kg CO^R2^Req/kg]

Carbon dioxide (CO^R2^R), fossil 1 1

Carbon dioxide (CO^R2^R), regenerative 0 0

Methane (CH^R4^R), fossil 30 21

Methane (CH^R4^R), regenerative 28 18.25*

Nitrous oxide (N^R2^RO) 265 310

Source: (IPCC 2013) (IPCC 1995)

*Excluding the stoichiometrically calculated GWP of fossil CO^R2^R after conversion of methane in the atmosphere Carbon dioxide and methane emissions are distinguished according to their origin. Regenerative me-thane (from the conversion of organic substances) has a lower GWP than meme-thane from fossil sources, because regenerative carbon dioxide – produced from the methane over time as a result of oxidation in the atmosphere is treated as climate-neutral.

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