By Sergio Goncalves and Isla Binnie LISBON (Reuters) – The European Commission has agreed to allow Spain and Portugal to place a temporary cap on reference prices for natural gas and coal used by power plants of 40 euros per megawatt-hour, their ministries in charge of energy and the environment said on Tuesday. European countries are struggling to manage surging gas and power prices, pushed higher by Russia’s invasion of Ukraine, and to cushion their effect on voters’ spending power. “The (political) agreement allows (us) to protect consumers exposed to the market,” Portugal’s Environment Min…