In 2011 it signed a new maintenance and emergency response contract covering its gas pipelines with Scotia Gas Networks (SGN). However, the Moyle Interconnector – which links the electricity grids of Scotland and Northern Ireland but operates only at 50% capacity due to a long-running fault – is not part of the arrangement. Mutual Energy is a company limited by guarantee which holds energy infrastructure assets for the benefit of the energy consumers. SGN is the second largest gas distribution network in the UK serving around 5.8 million homes in Scotland and the south and south-east of England. It delivers gas to cities such as London, Glasgow and Edinburgh as well as more remote areas in Scotland, such as Stornoway and Oban. It was formed in 2005 and is owned by three shareholders – SSE plc (50%), Borealis Infrastructure Europe (UK) Limited (25%) and Ontario Teachers' Pension Plan Board (25%).