ISTANBUL

Investigation into the cause of electricity outage across the country is still in progress, Turkish energy minister said Thursday. 

Taner Yildiz spoke on the country's power blackout which hit the whole country earlier Tuesday, including capital Ankara and the country's biggest city, Istanbul, during the opening ceremony of an oil conference in Istanbul.

Yildiz said the location of the start of electricity outage is known but research is still underway as to its cause. 

Yildiz confirmed the Ataturk Hydroelectric Dam; the biggest dam in the country, overloaded the electricity transmission system which triggered the Cukurova region's distribution system to power down. This in turn caused electricity plants in Izmir province in western Turkey to trigger the power outage.

Turkey's electricity transmission system is the second biggest system among European countries, Yildiz underlined. He added that Turkey's system is on par with those of EU member states.

Turkey's 1.2 million kilometer-long transmission system and the system equipment used are up to western standards, Yildiz said, adding the U.S. experienced a 36-hour-long power cut in 2003. 

Turkey currently relies heavily on foreign natural gas for its electricity production, but is actively attempting to diversify its electricity production through plans to build two nuclear power plants in the future.

In a late night session Tuesday, the Turkish parliament approved an intergovernmental agreement to build a nuclear power plant in the Black Sea province of Sinop with Japan.

"In the construction of the nuclear power plant a project firm will be establish with $3 billion and will reach to $22 billion over the years," Yildiz said. He added that the nuclear power plant will increase the country's energy supply security.

The plant to be built in Sinop is expected to begin in 2017 and to produce 40 billion kilowatt-hours of electricity every year with its four reactors. 

The nuclear project will be constructed by a French-Japanese consortium with a share from Turkey’s state-owned energy company EUAS. The agreement between the Turkish and Japanese governments to build the plant was signed in 2013.