Ed Miliband has reaffirmed the UK’s ambitious 2030 clean power goal with the biggest ever expansion of offshore wind farms that could add as much as £1.8bn a year onto households’ energy bills. The government unveiled an auction of offshore energy sites with a total capacity of 8.4 gigawatts, far outstripping analyst estimates and enough to power roughly 12m homes. Miliband, the secretary of state for energy security and net zero, hailed the new wind farms as a “monumental step towards clean power by 2030” that will…