1 Use of commingling to avoid propane addition at biomethane injection points  Objective of the measurement regime for CV  Protect downstream customers  Comply with Gas (Calculation of Thermal Energy) Regulations  At suitable locations where sufficient gas grid flow exists, commingling may be sufficient to produce a blended CV that does not trigger CV “cap”  CV of “pure” biomethane flow measured and used to establish energy content of gas input (and for RHI purposes) but not for testing against the local network CV re triggering CV cap  CV of commingled flow measured downstream of blending point and tested against network CV for purposes of CV cap

2 Remote CV monitoring at Adnams

3 Example of how this works in practice – based on Adnams  Biomethane flow CV = 36.6 MJ/m3 (120 m3/h max)  Network FWACV = 39.6 MJ/m3  Minimum flow to blending point = 5 * BM flow  Worst case blended CV = 39.1 MJ/m3  This is 0.5 MJ/m3 less than Network FWACV; does not trigger cap  If biomethane flow were included in area FWACV calculation, it would have negligible effect on FWACV  No consumers supplied with gas prior to blending

4 Conclusions  Blending and remote CV monitoring can in some cases avoid the need for propane addition  In other cases blending can limit the period for which propane addition is required (and/or the volume of propane to be input) to periods of low network flow  Financial benefit to biomethane producer  Environmental benefit from mitigating fossil fuel addition  GDNs should be incentivised to identify and implement commingling opportunities