Hooking up the UK’s electricity system to neighbouring countries through a European “supergrid” could bring a host of economic and environmental benefits, but there are “tremendous uncertainties” about the overall value because of the very high costs involved, MPs have reported. The idea of a supergrid, long espoused by renewable energy supporters, is that an international network of electricity cables would link clean power sources, such as wind or solar farms, into the transmission system, and allow electricity to be traded across national borders. Some proponents envisage a future in which warm, southern Europe, and possibly the deserts of northern Africa, supply the continent with solar power, while wind power is produced in chillier northern parts and the North Sea. Though estimated to cost tens of billions of pounds, the notion has particular appeal in Britain because, as a new report by the energy and climate change select committee says, “at the moment, the UK is virtually an electricity island”, even though it is a world leader in offshore wind power. “We potentially have enough wind, wave and tidal energy to more than match our North Sea oil and gas production, and transform the country from a net energy importer to a net energy exporter,” said Tim Yeo, committee chairman. “If we continue to develop these renewable resources site-by-site it could be prohibitively expensive with large individual connections for each power plant.” The committee’s report was welcomed by Friends of the Supergrid, a group of companies and organisations that lobby for the regulatory framework needed for such a network. It estimates first-phase costs alone could be about €28bn (£24.5bn), the report says. The MPs said that, “while the economic opportunities associated with a supergrid may be large, there are also tremendous uncertainties about the balance of costs and benefits, especially for UK consumers who may have to bear the cost of investment. “Centrica in particular warned us that ‘the total costs of a supergrid may outweigh the benefits’,” the report said. “Others were more confident about the overall benefits. RWE npower suggested that, although costs would be high, ‘the benefits of providing energy stability, price control, capital cost savings from integrated infrastructure and realising long term renewable energy targets whilst ensuring security of supply outweigh these costs’.” The Department of Energy and Climate Change has estimated that the cost of connecting renewables resources in the North Sea could be in the region of £15bn-£20bn during the next decade, but the select committee said it had not made any assessment of the costs of a more integrated grid including interconnection. European Union officials, meanwhile, have estimated offshore grid development in the North and Baltic Seas would cost €32bn by 2020, leading to a total of €90bn by 2030. The committee said there are also problems when it comes to dividing up the costs of shared transmission assets between different countries. While some say this can be overcome, the committee said: “To us, this seems over-optimistic and completely ignores the fact that the substantial extra costs involved will eventually be borne by consumers. As our recommendations indicate, we believe that there will be some need for government to provide a framework and some funding if a supergrid is to get started.”