Kelda Water Services and its sister company Yorkshire Water are supplying the council with the biogas, which is produced at their sewage treatment works in Sheffield.
Ofwat has in fact been a little softer recently, ahead of its review for 2005-10: last winter it gave both Kelda and Severn Trent permission for interim price rises, and its chief, Philip Fletcher, admits that prices must rise to encourage investment in pipes and pumps.