Russia’s plans to drop Ukraine as a route for pumping natural gas to Europe will leave Gazprom facing about 1 billion dollars in annual transit fees to Slovakia and Bulgaria, industry sources say, quoted by Euractiv.com.

Moscow wants to circumnavigate Ukraine to pipe its gas to Europe because of pricing disagreements, which at times have led to disruptions in supplies to the European Union, but doing so will come at a cost which some analysts say is too high.

Billions of euros will be needed to build and expand alternative routes, and the route of the existing pipeline means transit fees to Slovakia and Bulgaria will have to be paid by Gazprom, even if Russia manages to bypass Ukraine by 2020.

Under the contracts with the two countries, which ship gas on to Western and Southern Europe respectively, Gazprom will have to pay Slovakia until 2028 and Bulgaria until 2030 regardless of whether they actually ship any gas through them.

The route through Slovakia is the key for gas flows to some of Gazprom’s biggest clients, Italy and Germany. “This is the biggest issue – no-one knows what to do with this [Slovakia] contract,” a Gazprom source said.

Slovakia’s Eustream had revenues of 630 million euros last year, down from 697 million euros in 2013, and most of this came from Gazprom, the company’s accounts and Reuters calculations show.

Another 90 million euros were charged by Bulgaria, according to Bulgarian state company Bulgartransgaz. The combined transit fees of both countries were about the same as a quarter of Gazprom’s net income last year.

Ukraine’s state gas firm, Naftogaz, earned about 2 billion dollars in transit fees from Gazprom last year, according to its reports, equal to about 6% of Ukraine’s budget revenues.