Bulgaria will hold auctions for a total of six shale gas exploration blocks, said Kristalina Stoykova from the Geological Institute at the Bulgarian Academy of Sciences (BAS).

Stoykova heads a scientific group in charge of shale gas research in Bulgaria.

In her words, four of the blocks that will be auctioned off are located in North-East Bulgaria and two other in North-Central Bulgaria.

At this stage, US oil and gas giant Chevron has won a contract to carry out shale gas exploration works near the town of for Novi Pazar in North-East Bulgaria. '

According to the estimates of the bidders, the deposit near Novi Pazar contains between 300 billion and 1 trillion cubic meters of shale gas.

A few days ago, local authorities said they would appeal the government's decision to sign a contract for shale gas exploration and production.

The tender procedures for the other shale gas exploration blocks have not been finalized yet.

According to Stoykova, shale gas exploration does not differ from conventional oil and gas drilling, with Bulgaria already hosting over 2000 such platforms.

Stoykova dismisses the risk of water and soil contamination as a result of shale gas exploration.

Shale gas remains a contentious issue in Bulgaria, with environmentalists and people residing near designated exploration blocks stressing the water, soil and air pollution and the seismic risks, while energy experts put the benefits of energy diversification at the forefront.

According to Bulgarian Energy Minister Traicho Traikov, a strong proponent of shale gas drilling, domestic shale gas deposits should suffice to guarantee the country's natural gas consumption for the next 1000 years.

The Bulgarian Socialist Party (BSP), however, has called for holding local referendums before giving the green light to shale gas exploration and extraction.