The main issues that Bulgaria needs to stress on in its energy policy are diversification and transparency, stated US Energy Envoy for Eurasia Richard Morningstar, who is on an official visit to Sofia.

Thursday Morningstar met Bulgarian President Rosen Plevneliev, to discuss Bulgarian-American partnership in the field of energy.

Morningstar was sent to Bulgaria by his superior, US Secretary of State Hillary Clinton, whose Sunday visit in Sofia included an important energy component.

Clinton argued that the US and Bulgaria could and need to cooperate in the fields of nuclear energy and natural gas.

The Bulgarian Parliament has recently imposed a ban on the exploration and production of shale gas in the country via the environmentally hazardous technique known as hydraulic fracturing.

But US energy giant Chevron has expressed a strong interest in Bulgarian shale gas, and had already obtained an exploration permit by the Bulgarian government before the ban.

At the same time, over 90% of Bulgaria's gas needs are satisfied by Russian state giant Gazprom, which has led commentators to see the US diplomatic visits as geared towards wresting Bulgaria from Russia's sphere.

"Energy diversification was a top priority in our talks with President Plevneliev. Diversification includes nuclear energy, natural gas deliveries and hydro power," said Morningstar.

Bulgaria relies on Russia for nuclear energy too, with the Kozloduy NPP receiving Russian supplies, and a fresh new Belene NPP planned with Russian company Atomstroyexport.

But US company Westinghouse has expressed an interest in building additional units at Kozloduy NPP.

"The main message from this meeting was the need for Bulgaria to be energy-independent, as well as the ways this can be achieved," commented Tihomir Stoychev, Bulgarian President Plevneliev's foreign policy secretary.

"In today's world energy is part of national security. Bulgaria's strategic relations with the USA include the energy sector," added Stoychev.

He recalled Bulgarian President Rosen Plevneliev principles of energy diversification, energy liberalization and energy effectiveness.

Monday-Wednesday Bulgarian Minister of Finance Simeon Djankov and Minister of Economy and Energy Traicho Traikov visited Moscow to discuss joint energy projects with Russia.

Next week Gazprom CEO Alexei Miller is expected for talks in Sofia.