The minimum investment in maintaining the stable operation of Ukraine's gas transportation system (GTS) is $200-300 million annually with the existing volumes of transit work, Chairman of Naftogaz Ukrainy Andriy Kobolev has said.

"The Ukrainian GTS has been audited by Mott MacDonald, which clearly defined the minimum amount of investment needed to maintain the system in case of transit at the existing level. This is approximately $200-300 million per year," he said on the air of the Priamy TV Channel.

Kobolev noted that revenues received from gas transit in 2017 will amount to about $3 billion.

"It is mathematically absolutely possible to find $300 million from $3 billion. Therefore from the point of view of payback, from the point of view of self-sufficiency, this is a self-sufficient and financially stable business at the current level of income," he said.

According to him, statements about the cost of modernization of the Ukrainian GTS from the Russian side are overstated.

"I think that if to give the contract to upgrade Ukraine's GTS to Mr. Rotenberg, the figure could be $30 billion, it could even $50 billion," he added.