Anaerobic Digestion: Difference between revisions

Line 6:

==Overview==

'''Anaerobic Digestion''' (AD) is a process where biodegradable material is broken down by micro-organisms in the absence of oxygen in an enclosed vessel. [[Biogas]] is produced that can be used for the generation of power (electic and heat), or refined and used as a biomethane, and [[Digestate]] is produced which can be used as a biofertiliser.

'''Anaerobic Digestion''' (AD) is a process where biodegradable material is broken down by micro-organisms in the absence of oxygen in an enclosed vessel. [[Biogas]] is produced that can be used for the generation of power (electic and heat), or refined and used as a 'biomethane', and [[Digestate]] is produced which can be used as a 'biofertiliser'.

The process of AD occurs in several stages and requires a community of micro-organisms:

# Hydrolysis - large, complex polymers like carbohydrates, cellulose, proteins and fats are broken down by hydrolytic enzymes into simple sugars, amino acids and fatty acids.

Line 16:

===Feedstock===

Anaerobic Digestion uses biodegradable waste materials from a range of different sources, and can be delivered in a range of different ways (although Sewage Sludge doesn't tend to be blended with other AD delivery options as it then becomes impossible to to deliver and [[End of Waste Criteria|End of Waste]] compost:

Anaerobic Digestion uses biodegradable waste materials from a range of different sources:

* [[Food Waste]]

* [[Agricultural Waste]] such as manure and slurry

* [[Sewage Sludge]]

* Crops (including maize, grass ~~siliage~~, energy beet and whole crop cereals).

* Crops (including maize, grass silage, energy beet and whole crop cereals).

AD plants tend to be broadly categorised into '''Food AD''' and '''Farm AD''' projects (the former being 'pure' [[Food Waste]] and the latter being either single stream (i.e. based on manures alone) or multi-streamed (i.e. based on a mix of crop and/or manure and/or [[Food Waste]]). [[Sewage Sludge]] doesn't tend to be blended with other materials and tends to be a dedicated AD solution in its own right - primarily as it becomes impossible to to deliver [[End of Waste Criteria|End of Waste]] compost with the introduction of [[Sewage Sludge]] as an input feedstock. In any event, where the process utilises [[Animal By-product Material]], it must comply with the [[Animal By-Products (Enforcement) (England) Regulations 2011]] requirements.

~~Where~~ the process utilises [[Animal By-product Material]], it must comply with the [[Animal By-Products (Enforcement) (England) Regulations 2011]] requirements.

In addition, AD projects are required to report on their [[Biomass Sustainability]] under the [ROC]], [[FIT]] and [[SEG]] schemes, which demonstrates sustainability of the [[biogas]] produced based upon:

In addition, AD projects are required to report on their '''[[Biomass Sustainability]]''' under the [[ROC]], [[FIT]] and [[SEG]] schemes, which demonstrates sustainability of the [[biogas]] produced based upon:

* meeting greenhouse gas criteria and is made from solid biomass (i.e. ~~crops~~) that also meets the land criteria

* meeting greenhouse gas criteria and is made from solid biomass (i.e. Farm AD based on a crop such as maize) that also meets the land criteria

* is made from feedstock which is waste or

* is made from feedstock which is waste (i.e. Food AD) or

* consists of both of the above.

* consists of both of the above (i.e. Farm AD that is multi-streamed).

===Biogas===

Line 46:

Line 43:

==Growth in Anaerobic Digestion==

An analysis of the data provided by National Statistics<ref>https://www.gov.uk/government/statistics/monthly-small-scale-renewable-deployment</ref> for the monthly [[FIT]] commissioned installations over the period of the schemes existence shows an increase from 1 plant prior to 2010 to 427 plants by March 2019, generating 294.9MW of power.

{| class="wikitable"

|-

| [[File:No. AD Plants Installed.png|400px|centre|Feed in Tariffs: Cumulative Number of Installations 2010 to 2019 - Generated from National Statistics data]] || [[File:AD MW Capacity Installed.png|400px|centre|Feed in Tariffs: Cumulative Capacity Installed 2010 to 2019 - Generated from National Statistics data]]

|}

The graphs show the slowing of the cumulative growth in capacity from late 2016, linked to a change in the amounts payable under the [[FIT]] scheme

{| class="wikitable"

|-

! Capacity !! Cumulative Number of Plants Installed||% Split||Cumulative Capacity Installed(MW)||% Split

|-

| <=250kW ||133 ||31%||23.7||8%

|-

| 250-500kW || 166||39%||80.1||27%

|-

| 500-5MW || 128||30%||191.1||65%

|-

| Total || 427||100%||294.9||100%

|}

The table shows that by 2019, whilst the size of plants were relatively evenly distributed amongst the 3 bands of measurement/scales of plant, the larger scale projects had a disproportionally large installed capacity.

==Number of UK Sites==

@@ Line 6: / Line 6: @@
 ==Overview==
-'''Anaerobic Digestion''' (AD) is a process where biodegradable material is broken down by micro-organisms in the absence of oxygen in an enclosed vessel. [[Biogas]] is produced that can be used for the generation of power (electic and heat), or refined and used as a biomethane, and [[Digestate]] is produced which can be used as a biofertiliser.
+'''Anaerobic Digestion''' (AD) is a process where biodegradable material is broken down by micro-organisms in the absence of oxygen in an enclosed vessel. [[Biogas]] is produced that can be used for the generation of power (electic and heat), or refined and used as a 'biomethane', and [[Digestate]] is produced which can be used as a 'biofertiliser'.
 The process of AD occurs in several stages and requires a community of micro-organisms:
 # Hydrolysis - large, complex polymers like carbohydrates, cellulose, proteins and fats are broken down by hydrolytic enzymes into simple sugars, amino acids and fatty acids.
@@ Line 16: / Line 16: @@
 ===Feedstock===
-Anaerobic Digestion uses biodegradable waste materials from a range of different sources, and can be delivered in a range of different ways (although Sewage Sludge doesn't tend to be blended with other AD delivery options as it then becomes impossible to to deliver and [[End of Waste Criteria|End of Waste]] compost:
+Anaerobic Digestion uses biodegradable waste materials from a range of different sources:
 * [[Food Waste]]
 * [[Agricultural Waste]] such as manure and slurry
 * [[Sewage Sludge]]
-* Crops (including maize, grass siliage, energy beet and whole crop cereals).
+* Crops (including maize, grass silage, energy beet and whole crop cereals).
+AD plants tend to be broadly categorised into '''Food AD''' and '''Farm AD''' projects (the former being 'pure' [[Food Waste]] and the latter being either single stream (i.e. based on manures alone) or multi-streamed (i.e. based on a mix of crop and/or manure and/or [[Food Waste]]). [[Sewage Sludge]] doesn't tend to be blended with other materials and tends to be a dedicated AD solution in its own right - primarily as it becomes impossible to to deliver [[End of Waste Criteria|End of Waste]] compost with the introduction of [[Sewage Sludge]] as an input feedstock. In any event, where the process utilises [[Animal By-product Material]], it must comply with the [[Animal By-Products (Enforcement) (England) Regulations 2011]] requirements.
-Where the process utilises [[Animal By-product Material]], it must comply with the [[Animal By-Products (Enforcement) (England) Regulations 2011]] requirements.
-In addition, AD projects are required to report on their [[Biomass Sustainability]] under the [ROC]], [[FIT]] and [[SEG]] schemes, which demonstrates sustainability of the [[biogas]] produced based upon:
+In addition, AD projects are required to report on their '''[[Biomass Sustainability]]''' under the [[ROC]], [[FIT]] and [[SEG]] schemes, which demonstrates sustainability of the [[biogas]] produced based upon:
-* meeting greenhouse gas criteria and is made from solid biomass (i.e. crops) that also meets the land criteria
+* meeting greenhouse gas criteria and is made from solid biomass (i.e. Farm AD based on a crop such as maize) that also meets the land criteria
-* is made from feedstock which is waste or
+* is made from feedstock which is waste (i.e. Food AD) or
-* consists of both of the above.
+* consists of both of the above (i.e. Farm AD that is multi-streamed).
 ===Biogas===
@@ Line 46: / Line 43: @@
 ==Growth in Anaerobic Digestion==
+An analysis of the data provided by National Statistics<ref>https://www.gov.uk/government/statistics/monthly-small-scale-renewable-deployment</ref> for the monthly [[FIT]] commissioned installations over the period of the schemes existence shows an increase from 1 plant prior to 2010 to 427 plants by March 2019, generating 294.9MW of power.
+{| class="wikitable"
+|-
+| [[File:No. AD Plants Installed.png|400px|centre|Feed in Tariffs: Cumulative Number of Installations 2010 to 2019 -  Generated from National Statistics data]] || [[File:AD MW Capacity Installed.png|400px|centre|Feed in Tariffs: Cumulative Capacity Installed 2010 to 2019 -  Generated from National Statistics data]]
+|}
+The graphs show the slowing of the cumulative growth in capacity from late 2016, linked to a change in the amounts payable under the [[FIT]] scheme
+{| class="wikitable"
+|-
+! Capacity !! Cumulative Number of Plants Installed||% Split||Cumulative Capacity Installed(MW)||% Split
+|-
+| <=250kW ||133 ||31%||23.7||8%
+|-
+| 250-500kW || 166||39%||80.1||27%
+|-
+| 500-5MW || 128||30%||191.1||65%
+|-
+| Total || 427||100%||294.9||100%
+|}
+The table shows that by 2019, whilst the size of plants were relatively evenly distributed amongst the 3 bands of measurement/scales of plant, the larger scale projects had a disproportionally large installed capacity.
 ==Number of UK Sites==