Skip to content

Biogas and biomethane sustainability: calculator changes and policy development

As we mentioned several times on these blogs towards the end of last year, we spent a large amount of time with some members contributing to the development of the biomass and biogas carbon calculator. Thank you to those members who contributed to that work. Although only a limited amount of resource from DECC was available for revisions, there should be some significant improvements, and we now expect it to be published in a few weeks' time. We will of course let you know when it is available. 

With RHI criteria due to come in for new and existing plants from October 2015, this year will see some important work on the development of sustainability criteria and guidance towards them – not least as DECC have stated that they see the current RHI criteria as a temporary position. For now, however, there are two important areas we need input on: guidance for using the calculator, and further developments to the calculator itself. Later in the year we will need to consider wider policy changes for DECC. 


Calculator guidance

DECC have directly asked for input on which areas of the calculator developers and operators need explicit guidance. They will then commission E4tech, who have developed and revised the calculator, to produce this guidance. It will cover basic use of the calculator, so they are really looking for views on the key areas where users have encountered problems. 

One key question is whether biogas and biomethane should have separate guidance compared to woody biomass. Our instinct is that they should, as there are some very different issues (notably around the definition of a 'consignment' of fuel, and the fact that biomass users can use an approved supplier list), but we would be interested in any further views. In addition, evidence of areas where the calculator currently works for biomass but not biogas would be useful. 

As a starting point, we have identified some key areas we think the guidance needs to cover. We would be grateful for opinions on these, and any other areas which you think should be there.

  • Clear system boundaries for the expected start/end points
  • What should an operator define as a 'consignment' of feedstock, including where feedstocks are mixed in a silage clamp before digestion
  • How do you add feedstocks which are not in the default chain?

This needs to be a simple step by step process, and should include how an operator can provide evidence for their input values.

  • How do you provide evidence for variation from the calculator default values
  • How should emissions be allocated to heat and digestate as co-products 

If you have any thoughts, please let me know by Friday 16 January, via


Further calculator revisions

Significant further changes are needed to make the carbon calculator more appropriate for AD feedstocks.

These could include, for example further default feedstocks. Rye is being added to the existing list (maize, grass, beet and wheat) – should any other crops be added too?

However, issues such as the way in which emissions are apportioned to digestate or changing the approach to consignments would need a policy change from DECC. 

We will continue to work closely with E4tech, as they are likely to have views on other possible changes as the calculator developers. If there is anything else which we should be calling for, though, now is the time to let us know. 

If you have comments or questions on any of the content here, please let me know via or on 020 3176 0591.

Back To Top