Russian businessman Konstantin Grigorishin, with 95% of his assets in Ukraine, supports the return of some assets of DTEK energy holding in heating generation to the state.

"You needn't look hard with DTEK. The company's assets in heating generation were privatized arguably and non-transparently, so they are to be returned to the legal owner – the state," he said in an interview with Ukrainska Pravda publication.

He said that this business is not interesting for him.

"I don’t think that Ukrainian heating generation is a promising investment and I've never thought it was. I had a lot of opportunities to participate in its privatization since 1990s. Maybe, if I did not take part, I have my vision. It is strange to invest in Ukrainian generation now," Grigorishin said.

He said that coal-fueled heating generation from 2010 to 2014 enjoyed the preferences of the state regulator when the tariffs for transmission of heating for thermal power plants grew non-proportionally high compared to other electricity generators, such as national energy company Ukrenergo.

"As of early 2010, when [Viktor] Yanukovych became president, DTEK was a dynamically developing profit-making company, and the heating tariff was around 40-45 kopecks. In the first year it grew by 25%, in the second year – by another 25% and by 2013 it reached 80 kopecks. I remind [you] that inflation in the country was almost a zero, and the hryvnia exchange rate only strengthened," he said.

"We calculated that the unjustifiable increase was around 30 kopecks on average. If we multiply this unjustifiable increase of the tariffs from 2010 to 2013 by the number of kilowatt-hours generated by DTEK over the period and divide by the hryvnia exchange rate, it occurs that [businessman Rinat] Akhmetov's company received super profit of around $6 billion. With the arrival of the new government the situation did not change, and according to our estimates, DTEK received another $1 billion," he added.

Grigorishin also said that he helped in talks when Ukrinterenergo and Russia's Inter RAO signed a contract on supplies of Russian electricity to Ukraine. He said that the signing of the contract suspending the pressure of DTEK on the National Commission for Energy, Housing and Utilities Services Regulation (NCER) and the Energy and Coal Industry Ministry with demands to increase the tariff.

"As soon as the contract was signed, despite the huge resistance of the DTEK manager and the prime minister [Arseniy Yatseniuk], Akhmetov's company at once turned on its units and the problem disappeared. Thank God, there were no rotating blackouts after this," he said.

As reported, Grigorishin, along with assets in energy engineering (Sumy NPO, Zaporizhtransformator, minority holding in Turboatom), also controls Luhansk Energy Association and Vinnytsiaoblenergo. Jointly with Ihor Kolomoisky he also owns Chernihivoblenergo, Sumyoblenergo and Poltavaoblenergo. In addition, he has 30% of shares in Cherkasyoblenergo.

Three out of five heating generation companies are under the control of Akhmetov's DTEK – Skhidenergo (100%), Dniproenergo (72.9%) and Zakhidenergo (72.2%).

Donbasenergo (60.8%) is under the control of private joint-stock company Energoinvest Holding of Ihor Humeniuik and Centrenergo (78.3%) is owned by the state.