The so-called gas neutrality charge will be set at 2.99 euros ($3.16) per megawatt hour from the start of next year, up from 2.50 euros currently, THE said in a statement.

The hike reflects the fact that the volumes will be spread around fewer customers, it said, on the assumption that a law to restrict the surcharge to German customers only will be passed by the end of this year.

A spokesperson said THE processes allowed for factoring in possible delays to the lawmaking process. The Jan. 1 levy would be charged retroactively from end of March 2025, by which time there would be clarity, they added.

Germany said in May it planned to scrap the levy it charges neighbouring countries to buy gas from its reserves after Austria, the Czech Republic, Hungary and Slovakia complained to the European Commission, saying the measure hurt their efforts to quit Russian gas.

THE said it was assuming the legislation to scrap the charge would go through as planned. That has been called into question, given the loss of the Berlin coalition government's majority.

With wholesale front month European gas at around one-year highs of 46 euros per MWh, the charge could add 7%.

According to sources, the Commission had been expected to sue Germany for the charge, seen as flouting the EU's single market rules.

Originally a platform operator to manage Germany's gas market zone, THE has had an additional legal remit to ensure energy security in Europe's top economy since the 2022 energy crisis, when the invasion of Ukraine led to Russia's westwards gas exports being halted.

Its remit includes routinely revising the gas neutrality charge every six months.

It is also in charge of managing volumes and costs from certain parts of the traditionally privately-run gas cavern system, where THE owners include gas grids such as Gascade and Open Grid Europe.

Germany has 23 billion cubic metres of underground gas storage capacity, making it a big player internationally.

($1 = 0.9470 euros)