The merger will create the biggest electricity trader in the country, which will control 40% of the market.

The two companies, which launched the merger late last year, have made the commitment that they will not raise electricity prices for households for five years.

"We have been the cheapest for six years in a row, and nothing will change, we will continue to be the cheapest," Gen-I chairman Robert Golob told the press in Ljubljana.

Gen-I will enter Elektro energija, which is currently fully owned by Ljubljana-based distributor Elektro Ljubljana, with a capital injection to become the owner of a 50% stake.

This is expected to take place in 2016, but it is not known yet how much fresh capital the electricity trader and emerging gas supplier will provide as appraisals are still under way.

Elektro Ljubljana chairman Andrej Ribič added that Elektro energija was entering the merger "pretty healthy", as it operated positively and much better than last year.

The procedure is expected to be carried out throughout the entire 2016 and completed in 2017. There will be no changes for consumers as the Gen-I and Elektro energija brands will remain separated.

While the capital injection is the first phase of the merger, further steps will be set depending on the developments and are not envisaged before 2017, according to Golob.

He added that the two companies had actually been "afraid" of the merger as the green light by the market regulator had not been expected.

In addition to the commitment not to increase prices for five years, the merging companies have also committed to set up a firewall in relation to fuel retailer Petrol, which owns half of Gen-I.

The Competition Protection Agency will also be allowed to monitor the operation and price policy of the merged company for five years. "We have nothing to hide," Golob said, adding that the merger was about creating more added value for Slovenian companies and consumers.