2.1.2 Increasing adoption of waste and residue feedstocks

Agricultural feedstock (dedicated energy crops and agricultural and waste streams) was used for biomethane production in about 66% of installations in the EU in 2019.

Sustainable biomass25 is a feedstock for biogas and biomethane production and includes biomass from sequential agricultural cropping, forestry harvesting residues, animal manure, food waste, wastewater, and agricultural residues. In the EU, biomethane feedstock for anaerobic digestion comes from about 66% from agricultural feedstock (dedicated energy crops, and agricultural residues and waste streams), followed by (water) sewage sludge and other feedstocks (Figure 2.7). The production and conversion efficiency of biomethane depends on the quantity and quality of the feedstock. Feedstock can be dry or wet, which determines the digestion process (see Box 2).

Very large biomethane plants predominantly use bio- and municipal waste, industrial organic waste from food and beverage industries, and agricultural residues, manure, and plant residues (Figure 2.8).

Box 2. Definition of feedstock types from (GIE and EBA, 2020)

  • Agricultural residues, manure, plant residues: All substrates related to agricultural production except for energy crops. This includes manure, straw, cover/catch crops, and crop residues.
  • Dedicated energy crops: Primary crops with high starch content.
  • Industrial organic waste: Industrial organic waste for example from food and beverages industries.
  • Sewage sludge and waste: Sludge produced at a wastewater treatment plant.
  • Bio-and municipal waste: Municipal and organic household waste.
  • Landfill: Organic waste producing biogas collected on a landfill, sometimes referred to as landfill gas in literature.

In this report waste and residue feedstocks include the following categories from (GIE and EBA, 2020): agricultural residues, manure and plant residues; industrial organic waste from food and beverages industries; sewage sludge and waste; bio-and municipal waste; and landfill.

Dedicated energy crops are progressively making way for waste and residue26 feedstocks in new anaerobic digestion plants. Waste and residue feedstocks were used in about 63% of biomethane plants in the EU in 2019, up from approximately 40% of plants in 2012.

Although the biomethane market is growing, the type of feedstock used is changing from dedicated energy crops to waste and residue streams. The absolute share of biomethane production plants employing dedicated energy crops has flattened over the last few years, whereas their relative share has decreased (Figure 2.9).24, 27 Dedicated (energy)

crops are progressively making way for waste and residue feedstocks in new plants (see Box 2). The share of waste and residue feedstock in the EU increased from around 40% of total biomethane plants in 2012 to around 63% of total biomethane plants in 2019 (Figure 2.9).24, 27, 28 This trend can be explained through the flattening number of biomethane plants in Germany that mainly use dedicated energy crops compared to upcoming biomethane growing countries, such as France and Italy, which generally adopt waste and residue feedstocks (see also section 2.1.4). This trend is expected to continue in the coming years.

The relative use of feedstock varies by country. Figure 2.10 indicates the distribution of feedstock for EU countries with the largest number of biomethane plants based on the total number of plants in 2019.

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