Poland faces heavy fines for breaking EU laws on renewable energy use, officials said Wednesday, dealing a blow to an eastern European member almost entirely reliant on coal.

The senior legal advisor to the European Union's top court, advocate general Melchior Wathelet, said Poland should be fined 61,380 euros ($76,081) a day.

Warsaw had failed to fulfil its obligations under an EU energy and climate change deal aimed at cutting greenhouse gas emissions by 20 percent from 1990 levels by the year 2020, he said.

It failed to put EU rules on promoting renewable energy into Polish law, or to tell Brussels how it intended to do so, he said.

The case was originally brought by the European Commission, the executive body of the 28-nation EU which drafts and enforces laws for the bloc.

"Since it persisted in failing to fulfil its obligations... Poland should be ordered to pay a daily penalty payment of 61,380 euros effective from the date of the delivery of the Court's judgment," the advocate general said.

Legal opinions issued by the EU advocate general are not final but the European Court of Justice usually follows the recommendations when giving its judgement.

No date for the judgement was immediately available.

A country of 38 million that has seen steady economic expansion since it shed communism a quarter century ago, Poland is almost entirely reliant on coal for electricity.

Poland had threatened to veto a deal on new EU climate change targets for 2030 at a summit in October, arguing that it would be too expensive for it to meet the benchmarks.

It backed down after the deal included a compensation package for the countries that would be hardest hit.