However, even as Cristobal Montoro downplayed the possibility that such a tax would be imposed – saying that doing so would breach European law – he came under scrutiny for his ties to a Madrid-based lobbying firm that represents some of the country’s largest owners of renewables plants, such as Abengoa.

Last month Spain’s energy sector was rocked by leaked reports indicating that the government plans to impose a tax on generation at wind, solar and nuclear plants – all of which had been spared a similar tax placed on thermal generation in 2010.

Spain’s