By Jessica Frank-Keyes UK and EU energy firms are urging their governments to overhaul the post-Brexit trading set up in a bid to construct a North Sea “green power hub” and unlock investment. Some 20 top power firms and lobby groups have written an open letter to European and British energy ministers to urge them to prioritise a more efficient EU-UK electricity trade. “We are concerned that the EU and the UK will not achieve their objectives of fully developing the potential of the North Seas as long as electricity is traded using sub-optimal market mechanisms,” they wrote. It comes as the UK…