Anaerobic digestion (AD) facilities which provide biomethane to the grid may be forced to dilute their gas with propane, following concerns raised by gas regulator Ofgem.
It is believed that Ofgem is concerned that on a strict interpretation of The Gas (Calculation of Thermal Energy) Regulations 1996, which regulates calorific values for gas, the injection of biomethane to the grid may constitute a technical infringement because it is of too low a calorific value.
Bio Group chief executive Steve Sharratt, whose subsidiary is Adnams Bio Energy, told MRW: “The national grid are satisfied that in specific projects, of which ours is one, if you dilute green gas in the pipeline with considerable quantities of North sea gas, you don’t have a calorific value issue. We believed that was where Ofgem were at, but they’re stuttering.”
He added: “The energy companies involved don’t have an issue, national grid wouldn’t do anything that’s going to cause problems with the system and with regulation. We’ve got the Government saying they want to maximise biomethane from AD but we have a potential absurdity of not only adding significant cost - it’s a six figure capital cost, and annual running cost, but also putting fossil fuel in the system. It will affect everything that’s gas to grid, no doubt about that. It needs to be sorted in a sensible way.”
The issue has also attracted the attention of Suffolk Coastal MP Dr Thérèse Coffey, who said: “Adnams Biogas was set up by Bio Group and was the first to take methane and put it straight into the grid system. National Grid is happy with that, but Ofgem now seems to have a big issue with it. It seems ridiculous that we should have to add fossil fuel gases to natural gases in order to be greener.”
An Ofgem statement said: “The energy content of gas is not consistent around the country because Britain’s gas is supplied from a variety of sources which have different calorific values. Therefore, the quality of gas needs to be regulated by general legislation to protect consumers.”
“It would be unfair if a consumer receiving gas of a high calorific value were to be charged the same per cubic metre of gas as a consumer receiving a feed of gas with a low calorific value. Ofgem protects customers by ensuring that gas billing is based not only on the amount they use also on accurate calorific value. The gas industry defines the charging areas to help manage the varying gas quality, so that consumers are billed for energy they receive.”
“Gas supplied from biogas plants is typically lower quality in terms of its thermal energy in comparison to natural gas. Biogas producers such as Adnams can therefore blend biogas with propane to increase its calorific value making it compliant with the regulations. However, there are alternatives.”
Such alternatives include a redefinition of charging areas to account for the lower calorific value of biogas as a more long term solution to propane blending. However, the spokesman explained that Ofgem does not set or approve these charging areas, therefore such alternatives are “for the industry to take forward as it sees fit”.