ATHENS (Reuters) – Greece will impose supplementary tax bills on energy firms, its energy minister said on Thursday, after a regulator identified windfall profits stemming from elevated energy prices. European gas prices have soared since Russia, Europe’s top supplier, invaded Ukraine in February, raising fears of supply disruptions. With Greek households under pressure from inflation at a near 30-year high, the government had tasked the country’s energy regulator RAE with identifying windfall profits based on firms’ gross profit margins stemming from the higher gas prices. The government plan…