Hellenic Telecommunications Organisation S.A. is the largest technology company in Greece. It is one of the three largest companies listed in the Athens Stock Exchange, according to market capitalization.
Fluxys is a Belgium-based company, mainly acting as a natural gas transmission system operator. In 2004, it employed around 850 people and its infrastructure comprised about 3,700 km (2,300 mi) of pipelines and a terminal in Zeebrugge, Belgium. The company is listed on Euronext Brussels market.
National Grid plc is a British multinational electricity and gas utility company headquartered in London, England. Its principal activities are in the United Kingdom, where it owns and operates electricity and natural gas transmission networks, and in the Northeastern United States, where as well as operating transmission networks, the company produces and supplies electricity and gas, providing both to customers in New York and Massachusetts.
The State Oil Company of the Republic of Azerbaijan, largely known by its abbreviation SOCAR, is a fully state-owned national oil and gas company headquartered in Baku, Azerbaijan. The company produces oil and natural gas from onshore and offshore fields in the Azerbaijani segment of the Caspian Sea. It operates the country's only oil refinery, one gas processing plant and runs several oil and gas export pipelines throughout the country. It owns fuel filling station networks under the SOCAR brand in Azerbaijan, Turkey, Georgia, Ukraine, Romania, Switzerland, and Austria.
Shah Deniz gas field is the largest natural gas field in Azerbaijan. It is situated in the South Caspian Sea, off the coast of Azerbaijan, approximately 70 kilometres (43 mi) southeast of Baku, at a depth of 600 metres (2,000 ft). The field covers approximately 860 square kilometres (330 sq mi). Stretching out over 140 square kilometres, the reservoir is similar in size and shape to Manhattan Island.
Azeri–Chirag–Gunashli or Azeri–Chirag–Deepwater Gunashli is a complex of oil fields in the Caspian Sea, about 120 kilometres (75 mi) off the coast of Azerbaijan. It consists of the Azeri and Chirag oil fields, and the deepwater portion of the Gunashli oil field. An overall estimate of the area of the development is 432.4 square kilometres (167.0 sq mi). It is developed by the Azerbaijan International Operating Company, a consortium of international oil companies, and operated by BP on behalf of the consortium. The ACG fields have estimated recoverable reserves of about 5 to 6 billion barrels of petroleum. Peak oil production of 835,000 barrels per day (132,800 m3/d) was reached in 2010, however by the first quarter of 2022 production had declined to 434,000 barrels per day (69,000 m3/d), or about one-half of peak value. As of 2021, ACG oil accounted for 95% of all Azerbaijani oil exports.
Enagás, S.A. is a Spanish energy company and European transmission system operator (TSO), which owns and operates the nation's gas grid. The firm also owns four liquefied natural gas regasification terminals in the country, at Huelva, Barcelona, Cartagena and Gijon. In addition, it owns 50% of the plant BBG (Bilbao) and 72.5% of the Saggas terminal in Sagunto. The chairman of Enagás is Antonio Llardén Carratalá and his chief executive officer is Arturo Gonzalo Aizpiri. The firm's headquarters are located in Madrid. Apart from Spain, Enagás has presence in Mexico, Perú, Chile, Sweden and in the Trans Adriatic Pipeline (TAP) European project.
Public Gas Corporation of Greece A.E. commonly known for its Greek abbreviation DEPA is the natural gas supply company of Greece. The registered office of the company is based in Irakleio, Athens. It operates within the jurisdiction of the Ministry of Development. The current chairman is Ioannis Papadopoulos while Konstantinos Xifaras serves as CEO. In 2005, in order to liberalise the natural gas market, DESFA was created as a fully owned subsidiary to transport natural gas within Greece. Since then, DEPA sells gas to large consumers and to the gas supply companies. Natural gas is imported by pipelines from Bulgaria and Turkey and by liquefied natural gas at the Revithoussa LNG Terminal.
Trans Adriatic Pipeline is a natural gas pipeline proposed in 2003, constructed in 2016, and operational since 2020, from Azerbaijan at the Caspian Sea to Europe from Greece through Albania and the Adriatic Sea to Italy. It is a European section of the Southern Gas Corridor. As of 2022 capacity is 10 bcm per year.
Snam S.p.A. is an Italian energy infrastructure company. As of 31 December 2022, it had a market capitalization of €15.2 billion. Snam was originally a subsidiary of Italian energy company Eni. It has since become an independent company, whose largest shareholder is CDP Reti, a holding company controlled by the Italian state. The utility operates in Italy and, through associated companies, in Albania (AGSCo), Austria, China, France (Terēga), Greece (DESFA), the UAE and the United Kingdom. It is one of the main shareholders of the Trans Adriatic Pipeline (TAP). Snam is the main Italian operator for the transport and dispatching of natural gas in Italy, having almost all the transport infrastructures in Italy, with 32,727 km of gas pipelines in operation in high and medium pressure and over 41,000 km including international activities. First in Europe for natural gas storage capacity, the company is also one of the main continental operators in regasification for a total pro quota capacity of approximately 8.5 billion cubic meters per year. Snam is one of Europe's main regulated gas companies - leading Italy in gas transport and storage, while ranking third in regasification. Snam also aims to invest in new energy transition businesses to reduce environmental impact and decarbonisation: sustainable mobility, energy efficiency, renewable gases such as biomethane and hydrogen. The company is listed on the FTSE MIB index of the Borsa Italiana since 6 December 2001.
OPAP – Greek Organisation of Football Prognostics S.A. is a Greek company organizing and conducting games of chance. It is headquartered in Athens and for many years OPAP was a state-owned gambling monopoly. The company holds the exclusive rights to organize and manage numerical lotteries and sports betting in Greece. In 2013 the privatization of the company was completed through the sale of the State's remaining 33% stake to the Emma Delta investment scheme.
Dan Ulduzu field is an oil and gas field located 105 km (65 mi) northeast of Baku, Azerbaijan, west of Karabakh field, in the northern section of Absheron archipelago. In Azerbaijani, Dan Ulduzu means Pole Star.
Ashrafi field is an oil and gas field located 105 km (65 mi) northeast of Baku, Azerbaijan, west of Karabakh field, in the northern section of Absheron archipelago.
The Absheron gas field is an offshore natural gas field in the Caspian Sea. The field is located 100 kilometres (62 mi) southeast of Baku and 25 kilometres (16 mi) northeast of the Shah Deniz gas field. It covers approximately 270 square kilometres (100 sq mi).
The Trans-Anatolian Natural Gas Pipeline is a natural gas pipeline in Turkey. It is the central part of the Southern Gas Corridor, which connects the giant Shah Deniz gas field in Azerbaijan to Europe through the South Caucasus Pipeline and the Trans Adriatic Pipeline. The pipeline has a strategic importance for both Azerbaijan and Turkey. It allows the first Azerbaijani gas exports to Europe, beyond Turkey. It also strengthens the role of Turkey as a regional energy hub.
The EuroAsia Interconnector is a planned HVDC interconnector between the Greek, Cypriot, and Israeli power grids via the world's longest submarine power cable, with a length of 310 kilometres (190 mi) from Israel to Cyprus and 898 kilometres (558 mi) from Cyprus to Greece for a total of 1,208 kilometres (751 mi). Connecting Kofinou, Cyprus to Hadera, Israel and Korakias, Crete, Greece, the EuroAsia Interconnector is a major Project of Common Interest (PCI) of the European Union and a priority Electricity Highway Interconnector Project as an energy highway bridging Asia and Europe. Regulatory approval of electricity interconnection between Cyprus and Greece was completed on October 10, 2017.
Independent Power Transmission Operator S.A. is the Transmission System Operator for the Hellenic Electricity Transmission System. The mission of the company is the operation, control, maintenance and development of the national transmission system of Greece to ensure the reliable and efficient electricity supply, as well as the operation of the electricity market following the principles of transparency and equality.
The Hellenic Republic Asset Development Fund S.A. or TAIPED is a direct subsidiary of the Hellenic Corporation of Assets and Participations. HRADF exploits the assets of Greece that have been assigned to it and manages the implementation of the privatization program in Greece, and in specific, the implementation of the Asset Development Plan "ADP."
Athens International Airport S.A. or AIA is the airport authority that owns and manages Athens International Airport.
Enemalta plc is the only Maltese energy company. It provides energy services in the Maltese Islands and is entrusted with the distribution of electricity, and the development of the national electricity distribution network. It employs approximately 600 people.
€268.69 million (2017) [1] 
