Amber Rudd, U.K. energy secretary, speaks at the BritNed interconnector, a new 1-gigawatt electricity link between Britain and the Netherlands, operated as a joint venture between National Grid Plc and TenneT Holding BV, near Rochester, U.K., on Thursday, March 24, 2016. A U.K. vote to leave the European Union might force gas and power bills up by 500 million pounds ($700 million) a year, Rudd said on Thursday, warning that a "Brexit" would threaten Britain's energy security. Photographer: Chris Ratcliffe/Bloomberg via Getty Images
