Like other power producers, Acciona is weighing the costs of government plans to reform Spain's power market and address its so-called "tariff deficit".

Presenting the group's annual results, CEO José Manuel Entrecanales Domecq said: "We believe it is a major breach of investor confidence which will have a massive impact on [our profitability]."

Acciona claims renewables have suffered worst from the various measures announced by Spain, including a generation tax and tariff changes.

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