Big potential of cutting greenhouse gases from waste

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Source: European Environment Agency (EEA)

There is a big potential to cut greenhouse gases (GHGs) from municipal solid waste management, according to a new report from the European Environment Agency (EEA). The report, 'Waste opportunities – Past and future climate benefits from better municipal waste management in Europe', covers the EU-27 (excluding Cyprus), Norway and Switzerland. It estimates that these countries could make GHG savings of up to 78 million tonnes carbon dioxide equivalent (CO2-e) by 2020, or 1.53 % of Europe's emissions in 2008.

Biodegradable waste sent to landfill produces methane when the organic material decomposes anaerobically. Although this potent GHG can be captured and used to generate energy, much of it escapes into the atmosphere where it has a powerful climate forcing effect. Reducing the amount of waste going to landfill is therefore an important objective of EU waste policies.

Nonetheless, waste volumes continue to rise across the EU. The average EU citizen generated 468 kg of municipal solid waste in 1995, which increased to 524 kg in 2008. This could rise to 558 kg per person by 2020 unless effective policies are put in place to reduce waste generation.

The report takes a ‘life-cycle approach’ to calculating emissions from waste, considering all direct emissions from waste during processing and transport. In addition, it also accounts for emissions that are avoided in other parts of the economy – for example, accounting for the reduction of emissions when fossil fuels are displaced by energy recovered from waste. In this way, the method can show the potential impacts of various waste management strategies.

Especially recycling leads to avoided emissions. This is because recycling materials from municipal waste avoids emissions that would have been generated in extracting and processing virgin raw materials and these avoided emissions are higher than the emissions caused by the recycling processes. More details on the calculations, assumptions and data are available in this working paper.

Three different scenarios for 2020 illustrate that the potential for GHG savings largely depends on how countries implement EU waste policies, in particular whether they meet the EU Landfill Directive targets to reduce landfill of biodegradable municipal waste.

Key findings from three different scenarios

  • In a business-as-usual scenario, net GHG emissions from municipal waste management would be cut by 44 million tonnes CO2-e until 2020 compared to 2008. The two main factors responsible for this improvement are reduced methane emissions from landfill and increased avoided emissions through recycling.
  • If all countries fully meet the Landfill Directive’s waste diversion targets, potential life-cycle GHG emissions from municipal waste management in 2020 could be cut by 62 million tonnes CO2-e, which equals 1.23 % of their total GHG emissions in 2008.
  • A complete ban on landfilling could cut emissions even further, reducing potential net emissions from waste management in 2020 by 78 million tonnes CO2-e compared to 2008. For the sake of comparison, this is more than Hungary’s total emissions in 2008.

An analysis by the OECD , following a somewhat different but also life-cycle based approach, broadly confirms the findings of the EEA work, namely, that better management of municipal waste has a significant potential to reduce GHG emissions.

Encouragingly, ever more municipal solid waste is recycled and less is landfilled. The EU recycled 17 % of its municipal solid waste in 1995 and 40 % in 2008. In that period, the amount going to landfill dropped from 68 % to 40 %. These improvements have already cut annual net GHG emissions by 48 million tonnes CO2-e between 1995 and 2008 in the EU-27, Norway and Switzerland.

Kitchen and garden waste is the biggest fraction of municipal solid waste in most EU countries. This represents a sizeable opportunity to cut emissions through recycling and energy recovery – in 2008, 44 million tonnes of organic matter was composted, emitting 1.4 million tonnes CO2-e. If that had been subjected to anaerobic digestion, producing useful biogas, it could have cut 2 million tonnes CO2-e from Europe’s emissions.

In addition to climate concerns, increasing recycling and energy recovery also enhances resource efficiency, a main goal of the EU2020 strategy. However, even the most effective waste management strategy generates GHGs and causes the loss of resources. Authors note that the best strategy is avoiding generating waste in the first place.

Customer comments

  1. By Peter Hurrell on

    We disagree with the findings. The Greenhouse Gas Calculations are based upon a wrong premise and that does not fully account for the disproportionte differences between Methane and Carbon Dioxide....where the tCO2eq of Methane is 23 x the effect of tCO2 (in terms of the molecular masses of each molecule) and it is a fundamental flaw in the UNFCCC calculations that continue to promulgate the issue. The only realistic assessments of the impact is a Mass Balance of the decomposition and the best approximation of a typical biomass (or ligno-cellulose) core material where the lignin-cellulose-hemicellulose-ash ratios are given an atypical array of 30%/30%/30%/10% (in an equivalent dry mass) the modelling suggests that for each dry tonne of this biomass 2/3 a tonne of tCO2eq (being the combination of the degradation of the Cellulose and Hemi-Cellulose fractions of the Biomass (the Lignin and Ash contents do not decay) is avoided from the emission quotients and that this assumes that the active period of decomposition avoided for this first (one) tonne is 15 years. Then if you add to this the effects of subsequent years of avoided emissions for the second then third years through to the 15 year horizon of the first year of avoidance it doesnot take too much thought to determine that the total avoided from a 1 tonne continuing prevention of the Cellulose/Ligno-Cellulose material being land-filled and avoided tCO2eq is 75 tonnes over the stated period. That being the case if you then compare the Biomass content of Municipal Solid Waste alone from a community that produces 100 million tonnes per year of Biomass (or the Residues after Recycling) and take this as the dry component alone this becomes 7500 Million tonnes in the 15 year period which is far far higher than the calculations forfened here suggest. And there are two assumptions here which could be dramatically at variance and make things far worse: 1] the ratios we chose for Lignin to Cellulose to Hemi-Cellulose and Ash are we now likely to be at variance to those we have selected and they will more astutley resemble 28%/40%35%7% and give even higher degradation results; and 2] We have not discounted the effects of Recycling. So We ask again: these figures banded about here are they correct? We have passed Ours to eminent and learned authorities and they agree with us. We look to see this debate livened up.

  2. By Sahadev AnanthaKrishnan on

    Since we are dealing with similar problems related to the treatment of solid waste in Brazil I would like to know more about the equiment to dry solid waste so that it ca nbeusedfor combustion. Any information would be welcome. Thankyou S Ananthakrishnan( anantha@biotech.com.br)

  3. By Peter Hurrell on

    Sahadev AnanthaKrishnan: I am proposing to answer your enquiry through a multiple answering system in this media. What you have to view in your reviews are the facts that this is a much more complex issue than at first reviewed. The notion that Energy from Waste - by which it is assumed you are relating to Dry Energy rather than those which are Liquid Enegies or Gaseous Energies - presuposes that you need the results to reflect the needs of your process. We note that you are in Brazil, although you appear to have an - should I say - an Indian-originated name. If we converse through the impetus of this media link is it beholden upon us to publish what we say in this media? I am not sure about that, so if you do think so let me know in the normal run of things. Peter Hurrell