The decision to switch energy companies may not protect consumers from higher prices as the cost of grid expansion plans could amount to £4.7 billion.
Around 1,000 kilometres of additional cabling will be needed to link the UK's new nuclear infrastructure to the grid, as well as connecting the growing number of renewable energy projects.
Figures from the Electricity Networks Strategy Group suggest the investment could allow the UK to produce 30 per cent of its energy demand from renewable means within 20 years, but energy companies may have to increase consumer prices to pay for it.
Mike O'Brien, the energy and climate change minister, said: "This is a massive long-term investment opportunity and this upgrade work will help support jobs across the low-carbon economy."
The price of establishing new renewable energy projects such as offshore wind farms is growing steadily higher and the costs may filter down to the consumer as energy companies put together the necessary capital.
All the UK's major energy suppliers raised their prices in 2008.
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