Bulgaria and fossil gas

From Global Energy Monitor
This article is part of the Global Energy Monitor coverage of fossil gas
Sub-articles:

Nuclear and hydro play a significant role in Bulgaria's electricity generation. As of 2020, the two sources combined made up almost 50 percent of the energy generated in Bulgaria. However, in terms of Total Energy Supply (TES), Bulgaria remains heavily reliant on fossil fuels.[1] The National Energy and Climate Plan (NECP) calls for increasing the the share of renewable energy in the fuel mix and the integration of hydrogen into its energy and mobility systems.[2][3]

Bulgaria was not a significant producer of fossil gas in 2020, nor did it have large reserves.[4] It imports much of its gas supply from Russia.[2][5] Shale gas was proposed as an energy source in the late 2000s and early 2010s, but fracking was banned in Bulgaria in 2012.[6]

As of 2019, Bulgaria had seen a reduction in total GHG emissions since 1990 of 44 percent. According to the country's NECP, this is due to a reduction in energy-intensive enterprises, an increase of the aforementioned use of hydro and nuclear energy, increased efficiencies in housing, a shift from coal to fossil gas and "structural changes in industry."[7] However, as of 2020[8] was still the most GHG intensive economy in the European Union -- a fact credited to Bulgaria's continued reliance on coal.[7][1] Bulgaria, as the poorest country in the EU, does not have the same emissions reduction targets as its wealthier counterparts.[9]

As of 2022, Bulgaria had the eighth highest estimated cost of future EU gas pipelines and terminal: 2,574 million euros.[10]

Fuel mix (fossil fuels vs renewables)

Bulgaria's total energy supply by source
Bulgaria's total energy supply by source, 1990-2019. Per the IEA.[11]

In 2019, Bulgaria derived about 64% of its total energy supply (TES) from fossil fuels (27.15% from coal, 23.91% from oil, and 13.00% from fossil gas). 10.02% of the TES came from biofuels and waste, 1.59% from wind and solar, and 1.34% from hydro.[1]

The 2010 National Renewable Energy Action Plan set a overall target of 16% of share of energy generated from renewable sources in gross final energy consumptions (GFEC) - 24% of heating and cooling consumption, 21% of electricity, and 8% of transportation.[12]

Bulgaria's National Energy and Climate Plan (NECP) for 2021-2030 set a goal of increasing shares of renewables from a 2020 level of 21.4% to a 27.9% share of GFEC by 2030.[2]

Greenhouse gas emissions targets

Annual Co2 emissions from gas oil and coal in Bulgaria from 1965-2019. Data from the Global Carbon Project via the Fossil Fuel Policy Tracker[13]

As of 2020, Bulgaria's per capita CO2 emissions from fuel combustion (4.8 tCO2) were 19th in Europe.[14] In total, Bulgaria produced 49.61 million tons of GHG emissions -- about 71% of which came from the energy sector.[15][16]

In 2019, Bulgaria's total CO2 emissions were down 46.80% compared to 1990 levels.[1] In 2020, total GHG emissions 50.1% of what they were in 1990.[16] CO2 emission from gas stood at 5 million tons (MT), compared to 13 MT from oil and 20 from coal.[13]

Bulgaria set a 2030 target for greenhouse gas (GHG) emissions of -0% compared to 2005, as set in the Effort Sharing Regulation.[17][7] While wealthier countries in the European Union have higher reduction targets, poorer ones, such as Bulgaria are required simply not to increase emissions.[9]

Government energy agencies & other key players

National energy agencies

The Ministry of Energy is responsible for economic and energy policy in Bulgaria.[18]

Sustainable Energy Development Agency is an executive agency within the Ministry of Energy, it deals with "energy efficiency and renewable energy sources."[19]

Permitting agencies

Energy and Water Regulatory Commission grants licenses for the production of fuels and generation of energy.[20]

Regulatory agencies

Energy and Water Regulatory Commission regulates activities in the energy sector.[20]

Nuclear Regulatory Agency performs state regulation of nuclear energy and ionizing radiation.[21]

Electric utilities

Elektroenergien Sistemen Operator (ESO) holds a certification for transmission of electric power.[22][23] It is the independent transmission system operator of the Republic of Bulgaria.[24] ESO manages 15 thousand km of power lines and 297 electrical substations.[24] ESO is a subsidiary of Bulgarian Energy Holding.[25]

Gas Utilities

Bulgargaz EAD is the public supplier of natural gas.[26] As of 2022, Bulgargaz "owns the only license for the activity of ‘public supply of natural gas on the territory of the Republic of Bulgaria’ for a period of 35 years."[27]

Bulgartransgaz operates Bulgaria's fossil gas transmission and transit networks as well as a gas storage facility in the country.[26]

Both Bulgargaz and Bulgartransgaz are subsidiaries of Bulgarian Energy Holding.[26]

Leading energy companies

Bulgarian Energy Holding EAD (BEH) is a state-owned holding company comprised of electricity generation, supply and transmission, natural gas transmission, supply and storage, and coal mining companies. Its companies have 6.2 GW of power generation capacity, and its gas transmission network has a technical capacity of 7.4 bcm/y.[28] National Electric Company EAD is one of BEH's subsidiaries.[22]

Electricity usage

Installed capacity

As of 2021, Bulgaria's installed capacity was about 12.7 GW[2], with 600 MW (.05%) coming from gas-fired power plants.[2] 4.5 GW comes from coal, 3.2 GW from hydro, 2 GW from nuclear, 1.1 GW from solar, and 700 MW from wind.[2]

The countries national energy plan proposes building a new gas-fired power plant as well as 1.7 GW of renewables capacity.[8]

The installed generation capacities by generation type from 2018-2020 can be seen below:

Installed generation capacities connected to the Bulgarian power grid, according to ESO' Statistical pocketbook 2018,[29] 2019,[30] 2020[31] and 2021.[32]
2018[29] 2019[30] 2020[31] 2021[32]
Generation Type Installed Capacity (MW) Share (%) Installed Capacity (MW) Share (%) Installed Capacity (MW) Share (%) Installed Capacity (MW) Share (%)
Nuclear 2,000 16.0 2,000 15.7 2,000 15.6 2,000 15.4
Coal 4,481 33.0 4,475 35.1 4,365 34.0 4,475 31.7
Fossil gas 983 7.9 1,235 9.7 1,360 10.6 1,269 9.8
Hydro 3,208 25.7 3,211 25.2 3,213 25.0 3,213 24.7
Wind 700 5.6 701 5.5 701 5.5 705 5.4
Photovoltaic 1,052 8.4 1,059 8.3 1,121 8.7 1,246 9.6
Biomass 77 0.6 77 0.6 79 0.6 79 0.6
Total 12,501 100% 12,758 100% 12,758 100% 12,986 100%

In 2016, Bulgaria's installed capacity totaled 10.75 GW, ranking it 57th in the world.[33] 39% of that capacity came from fossil fuels, 20% from nuclear, 23% from hydro, and 19% from other renewable sources.[4]

In 2019, 13.6% of the country's combined heat and power (CHP) generation (1.2 GW electricity, 4.4 GW heat[34]) was fueled by fossil gas.[15]

The Sofia Iztok power station, with 186 MW of capacity as of 2022, is the largest operational gas-fired power plant in Bulgaria.[35][36]

Gas plants in Bulgaria, according to the Global Gas Plant Tracker as of 2021.
Gas plants in Bulgaria, according to the Global Gas Plant Tracker as of 2022. Pre-construction plants are shown in pink, operating in brown. For more information see the full dataset.[37][38]

Production

Bulgaria generated 40.7 TWh of electricity in 2020, sourced 5.60% from fossil gas.[1] The breakdown of Bulgaria's electricity generation by source, according to the Our World in Data, between 1990 and 2021 is shown below.[39]

2020[1] 2021[39]
Source GWh Share (%) GWh Share (%)
Coal 13,530 33.20 17,730 38.1
Oil 304 0.75 400 0.86
Fossil gas 2,284 5.60 2,740 5.89
Nuclear 16,626 40.80 16,480 35.42
Hydro 3,320 8.15 4,560 9.81
Waste 5 0.01 -- --
Wind 1,477 3.62 1,430 3.08
Biofuels 1,697 4.16
Solar PV 1,473 3.61 1,490 3.2
Other sources 36 0.09 1,690 3.64
Total 40,752 100% 46,520 100%
Source: Our World in Data based on BP Statistical Review of World Energy (2022); Our World in Data based on Ember's Global Electricity Review (2022); Our World in Data based on Ember's European [39]Note: 'Other renewables' includes biomass and waste, geothermal, wave and tidal.

Between 2020 and 2021, power generation increase by 9%, "mainly due to the coal-based thermal plants based and the hydropower plants in the country."[23]

With 42.29 TWh of electricity produced, Bulgaria ranked 57th in the world in 2016.[4]

With 2.15 TWh of electricity from fossil gas, Bulgaria ranked 19th in Europe in 2019.[15]

Consumption

Bulgaria's gross domestic electricity consumption was 38.4 TWh in 2019, a decrease of 1.1% compared to 2018.[2]

Bulgaria consumed 32.34 TWh of electricity in 2016, 60th in the world.[4]

Fossil Gas Production, Consumption, Sources and Projects in Bulgaria

Domestic Production

In 2020, Bulgaria's 0.05 Mtoe of fossil gas represented approximately zero percent of the nation's 10.83 Million Tonnes of Oil Equivalent (Mtoe) of energy produced.[16]

Bulgaria's 79.28 million cubic meters of fossil gas production in 2017 made it the 83rd largest producer in the world.[4]

The domestic production of fossil gas in Bulgaria between 2009 and 2019 is shown below (in Mtoe):

Bulgaria production of fossil gas in Mtoe, per the EU Commission.[15][16]
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
0.01 0.06 0.35 0.31 0.23 0.16 0.08 0.08 0.07 0.03 0.03 0.05
Production of fossil gas in Bulgaria between 1990 and 2020, per the EU Commission[16]

Gas exploration and production in Bulgaria occurs mostly in the northern part of the country and the Black Sea.[40] According to Wood Mackenzie, the two key onshore producing regions in Bulgaria are the Moesian platform and the Varna sub-basin.[41]

According to a 2014 paper, "Bulgaria’s conventional oil and gas production used to be significant before the 1990s but has declined significantly since then."[42]

Reserves

As of 2021, Bulgaria held an estimate 5.663 billion cubic meters of proven fossil gas reserves.[4][43]

As of 2014, Bulgaria's own reserves could only satisfy four percent of total consumption.[42] The Atlantic Council called Bulgaria "almost devoid of proved indigenous resources."[44]

According to KPMG, Bulgaria has prospects for new discoveries located offshore, which have triggered the interest of development companies. Additionally, "Bulgaria seems to have relatively large shale gas reserves" but fracking has been banned in the country since 2012.[45][42]

Consumption

In 2020, Bulgaria consumed 2.5 Mtoe of fossil gas, ranking it 13th in Europe.[46]

In 2017, Bulgaria consumed 2.95 billion cubic meters of fossil gas, the 70th most in the world.[4]

Imports & exports

Bulgaria's fossil gas imports and exports from 2006-2019 are shown below:

Bulgaria imports and exports of fossil gas in Mtoe, per the EU Commission.[16]
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
Imports 2.13 2.13 2.26 2.04 2.23 2.22 2.52 2.59 2.72 2.59 2.46 2.43
Exports 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.01 0.01 0.01

Bulgaria imported 2.4 Mtoe of fossil gas in 2020, ranking 15 in the European Union.[15][46]

Bulgaria exported 0.01 Mtoe of fossil gas in 2019, ranking 14 in the European Union.[15]

As of 2020, Bulgaria was 96.4% dependent on imports for its fossil gas supply.[16] Under a long-term contract with Russia (as of 2021, valid through 2022)[47], over 95 percent of Bulgaria's natural gas imports are delivered through a pipeline crossing Ukraine, Moldova and Romania.[2] In April 2022, Bulgaria halted gas deliveries from Russia's Gazprom which was supplying 90% of the the countries gas supply. In August 2022, Bulgaria's energy minister stated "talks with Gazprom to renew supplies are inevitable."[47]

According to the US International Trade Administration, "Bulgaria will import some 1 bcm of natural gas per year from the Shah Deniz II field in Azerbaijan for a period of 25 years under a contract between public gas supplier Bulgargaz and Azerbaijan’s state-owned oil and gas company SOCAR."[23]

Transport

Map of Gas Infrastructure in Bulgaria
Map of Gas Infrastructure in Bulgaria, created by Ikonact based on Bulgartransgaz TYNDP [48]

As of 2022, Bulgaria's network of natural gas pipelines spans 3,276 km.[49] A detailed map of the pipelines that make up the network can be found on Bulgartransgaz's website[50] and in the sidebar.

With 1,755.6 km of pipeline projects in development, Bulgaria ranked 19th in the world in terms of planned expansion by length in 2022.[51][52] With 139,179 BOE/d of pipeline projects in development, Bulgaria ranked 31st in the world in terms of planned expansion by capacity in 2020.[53]

The estimated total cost of new gas transport infrastructure (pipelines and LNG terminals) was 4,375 million euros in 2021.[54]

As of October 2022, there was at least 810 km of domestic gas transport pipeline projects in development.[55]

As of October 2022, the main gas international pipeline transport projects in development were:

Pipelines running internationally through Bulgaria, in-development as of October 2022, according to the Global Gas Infrastructure Tracker.[55][56]
Pipeline name Countries Status as of November 2022 Expected Start Year Length (KM) FID Status
Eastring Pipeline Slovakia, Hungary, Romania, Bulgaria, Turkey Proposed 2025 1,030-1,241 (route TBD) Pre-FID
Bulgaria-Serbia Interconnector Gas Pipeline Bulgaria, Serbia Construction 2023 170.00 FID
North Macedonia–Bulgaria Gas Pipeline North Macedonia, Bulgaria Proposed -- 110 Pre-FID

Bulgarian pipelines in-development, as of 2022 according to GGIT, can be seen on the map below:[55]

Proposed and under construction pipelines in Bulgaria as of November 2022, according to the Global Fossil Infrastructure Tracker. Proposed pipelines are shown in yellow and under-construction pipelines are shown in red. See the Global Gas Infrastructure Tracker Interactive Map for more information


Hydrogen

Bulgaria's NECP calls for the integration of hydrogen into its energy and mobility systems gradually by 2030. Fuel Cells and Hydrogen Joint Undertaking commissioned a study on the Role of Hydrogen in the National Energy and Climate Plans for Bulgaria. The study suggests that between 0.6 and 1.1 GW of dedicated renewable electricity capacity would be installed to produce green hydrogen via electrolysis. That energy then would be predominantly used in the transport and industry sectors.[3] To reach its renewable hydrogen target, Bulgaria expects total investments of around 3,45 million EUR.[3]

The Energy and Climate Integrated Plan of the Republic of Bulgaria for the period of 2021 – 2030 highlights significant potential for the development of hydrogen projects in transport and power generation.[57]

Bulgartransgaz plans in its 2022-2031 TYNDP for Hydrogen include: the "construction of infrastructure for transport of hydrogen and low-carbon gaseous fuels for supply of power plants and other consumers in Maritsa East Coal Basin; retrofitting of the existing gas transmission infrastructure for operation with up to 10% hydrogen; new hydrogen infrastructure between the Sofia region and the Bulgarian-Greek border in Kulata region."[58]

Renewable Potential

According to an OECD report, Bulgaria's shares for wind and solar power production are, as of 2021, "still far below the 2030 benchmarks." Wind and solar power potentials are shown below:

Global horizontal irradiation (kWh/m2). Map produced by The Global Solar Atlas, via OECD.org[59]
Mean wind power density (W/m2). Map produced by The Global Wind Atlas, via OECD.org[59]

Suspensions of Oil and Gas Exploration in Bulgaria

Beyond Oil and Gas Alliance

Bulgaria did not join the Beyond Oil and Gas Alliance (BOGA) at COP26 in 2021.[60][61]

Fracking Ban

In 2012, following "big street protests by environmentalists" Bulgarian parliament voted to ban exploratory drilling for shale gas.[6] This "protest-induced total ban" went into effect immediately and indefinitely. It forced companies that currently held license to prove no fracking was involved in their plans, further exploration tenders were cancelled.[42] The ban is still in effect as of 2022,[13] and no shale gas companies remain in the country.[62]

Socio-Economic Impact of the Fossil Gas Industry

Workforce

According to estimates cited by the European Commission, in 2019 there were four enterprises in the "Extraction of Crude Petroleum & Natural Gas" sector, nine in "Support Activities for Petroleum & Natural Gas Extraction" and 2,027 in "Electricity, Gas, Steam & Air Conditioning Supply." 12 people were employed in support activities for oil and gas extraction. 31,368 people were employed in the electricity, gas, steam, and air conditioning supply sector.[34][46]

Opposition to Fossil Infrastructure

In 2020, thousands took to the streets in a protest to "stop the amendments to the Biodiversity Act", reportedly due to potential harm to protected zones.[63]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 "bulgaria - Countries & Regions". IEA. Retrieved 2022-01-07.
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 75. "Bulgaria - Energy". www.trade.gov. Retrieved 2022-01-11.
  3. 3.0 3.1 3.2 Fuel Cells and Hydrogen Joint Undertaking (2020). "Opportunities for Hydrogen Energy Technologies Considering the National Energy & Climate Plans-Bulgaria" (PDF). European Commission- DG Energy. Retrieved January 12, 2022.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 "Bulgaria - The World Factbook". www.cia.gov. Retrieved 2022-01-06.
  5. 75. "Bulgaria - Energy". International Trade Administration | Trade.gov. Retrieved 2022-10-07.
  6. 6.0 6.1 "Bulgaria bans shale gas drilling with 'fracking' method". 2012-01-19. Retrieved 2022-01-12.
  7. 7.0 7.1 7.2 Yougova, Dessislava (February 2021). "Climate action in Bulgaria" (PDF). European Parliamentary Research Service. Retrieved January 11, 2022.
  8. 8.0 8.1 @NatGeoUK (2021-11-09). "As the EU targets steep emissions cuts, this country has a coal problem". National Geographic. Retrieved 2022-01-13.
  9. 9.0 9.1 "EU countries want emissions targets to stay linked to wealth -document". Reuters. 2021-05-11. Retrieved 2022-01-13.
  10. Aitken, Greig (April 2022). "Europe Gas Tracker 2022". Global Energy Monitor. Retrieved November 10, 2022.
  11. "Bulgaria - Countries & Regions - IEA". IEA. Retrieved 2022-10-04.
  12. "National Renewable Energy Action Plan (NREAP) – Policies - IEA". IEA. Retrieved 2022-10-04.
  13. 13.0 13.1 13.2 "Bulgaria: Policy Details". Fossil Fuel Policy Tracker. Retrieved November 3, 2022.
  14. "IEA Energy Atlas". International Energy Agency. Retrieved 2021-06-20.
  15. 15.0 15.1 15.2 15.3 15.4 15.5 EU Commission, DG Energy, Unit A4 (June 4, 2021). "Energy datasheets: EU countries". European Commission. Retrieved January 5, 2022.CS1 maint: multiple names: authors list (link)
  16. 16.0 16.1 16.2 16.3 16.4 16.5 16.6 EU Commission, DG Energy, Unit A4 (April 29, 2022). "Energy datasheets: EU countries". energy.ec.europa.eu. Retrieved October 4, 2022.CS1 maint: multiple names: authors list (link)
  17. European Commission. "Summary of the Commission assessment of the draft National Energy and Climate Plan 2021-2030" (PDF). European Commission. Retrieved January 11, 2021.
  18. "About us". www.me.government.bg. Retrieved 2022-01-12.
  19. "Sustainable Energy Development Agency - Stakeholders - ETIP-B-SABS 2". www.etipbioenergy.eu. Retrieved 2022-01-12.
  20. 20.0 20.1 "About EWRC". Republic of Bulgaria Energy and Water Regulatory Commission. Retrieved January 12, 2022.
  21. European Nuclear Safety Regulators Group (September 2020). "Bulgaria: Nuclear regulatory authority". ESREG. Retrieved January 12, 2022.
  22. 22.0 22.1 "Bulletin on the state and development of the Energy sector in the Republic of Bulgaria" (PDF). Ministry of Energy. 2015. Retrieved January 11, 2022.
  23. 23.0 23.1 23.2 75. "Bulgaria - Energy". International Trade Administration | Trade.gov. Retrieved 2022-10-04.
  24. 24.0 24.1 "ESO.BG - Електроенергиен Системен Оператор". eso.bg. Retrieved 2022-01-12.
  25. "Electricity System Operator EAD". bgenh.com. Retrieved 2022-01-12.
  26. 26.0 26.1 26.2 "Natural gas". bgenh.com. Retrieved 2022-01-12.
  27. "Bulgargaz EAD". bgenh.com. Retrieved 2022-01-12.
  28. "Bulgarian Energy Holding EAD". bgenh.com. Retrieved 2022-01-11.
  29. 29.0 29.1 Electricity System Operator (2018). "Statistical pocketbook 2018". ESO. Retrieved January 12, 2022
  30. 30.0 30.1 Electricity System Operator (2019). "Statistical pocketbook 2019". ESO. Retrieved January 12, 2022.
  31. 31.0 31.1 ЕСО ЕАД. "СТАТИСТИЧЕСКА КНИЖКА 2020". ESO. Retrieved January 12, 2022.
  32. 32.0 32.1 "STATISTICAL POCKETBOOK 2021". ESO EAD. 2021. Retrieved October 7, 2022.
  33. "Electricity – installed generating capacity - The World Factbook". www.cia.gov. Retrieved 2022-01-03.
  34. 34.0 34.1 Directorate-General for Energy (European Commission) (2021). "EU energy in figures: Statistical pocketbook 2021". Publication Office of the European Union. Retrieved December 5, 2021.
  35. "Global Gas Plant Tracker". Global Energy Monitor. 2021. Retrieved January 11, 2022.
  36. "Global Gas Plant Tracker". Global Energy Monitor. Retrieved October 26, 2022.
  37. "Global Gas Plant Tracker". Global Energy Monitor. 2021. Retrieved January 12, 2022.
  38. "Global Gas Plant Tracker". Global Energy Monitor. Retrieved October 26, 2022.
  39. 39.0 39.1 39.2 "Electricity production by source, Bulgaria". Our World in Data. 2022. Retrieved October 7, 2022.
  40. "Petroleum and Natural Gas Industry of Romania, Bulgaria and Moldova". www.see-industry.com. Retrieved 2022-01-12.
  41. Mackenzie, Wood (2020-10-21). "Energy Research & Consultancy". www.woodmac.com. Retrieved 2022-01-12.
  42. 42.0 42.1 42.2 42.3 Devey, Simon (2014). "Shale Gas U-Turns in Bulgaria and Romania: The Turbulent Politics of Energy and Protest". Journal of European Management & Public Affairs Studies – via Technische Hochschule Wildau.
  43. "Bulgaria - The World Factbook". www.cia.gov. Retrieved 2022-10-26.
  44. Nitzov, Boyko. "The Energy Sector of Bulgaria" (PDF). Atlantic Council. Retrieved January 12, 2022.
  45. "Oil & Gas - KPMG Bulgaria". KPMG. 2021-05-05. Retrieved 2022-01-12.
  46. 46.0 46.1 46.2 "EU energy in figures : statistical pocketbook 2022". op.europa.eu. corporate-body.ENER:Directorate-General for Energy. 2022-09-22. Retrieved 2022-10-26.CS1 maint: others (link)
  47. 47.0 47.1 "Bulgaria says talks to resume Russian gas supplies are 'inevitable'". Reuters. Retrieved 2022-10-26.
  48. Ikonact (November 14, 2020). "Map of Gas Infrastructure in Bulgaria". Wikimedia Commons. Retrieved January 12, 2022.
  49. "Gas infrastructure description". www.bulgartransgaz.bg. Retrieved 2022-01-12.
  50. "Gas Infrastructure of the Republic of Bulgaria". Bulgartransgaz. 2021. Retrieved January 12, 2022.
  51. "Kilometers of Gas Pipeline by Country and Project Status". Global Energy Monitor. November 15, 2021. Retrieved January 4, 2021.
  52. "Summary tables - GGIT (pipelines Jan 2022, terminals July 2022)". Google Docs. Retrieved 2022-10-26.
  53. "Gas Pipeline Capacity by Country and Project Status". Global Energy Monitor. December 21, 2020. Retrieved January 4, 2021.
  54. Inman, Mason (April 2021). "EUROPE GAS TRACKER REPORT 2021" (PDF). GLOBAL ENERGY MONITOR. Retrieved January 5, 2021.
  55. 55.0 55.1 55.2 "Global Fossil Infrastructure Tracker". Global Energy Monitor. January 6, 2022. Retrieved January 6, 2022.
  56. "Global Gas Infrastructure Tracker". Global Energy Monitor. Retrieved October 26, 2022.
  57. "HYDROGEN LAW AND REGULATION IN BULGARIA". CMS Law, Tax, Future. Retrieved January 12, 2022.
  58. "2022-2031 TEN-YEAR NETWORK DEVELOPMENT PLAN OF BULGARTRANSGAZ EAD" (PDF). Bulgartransgaz EAD. April 2022. Retrieved October 28, 2022.
  59. 59.0 59.1 "Bulgaria: Progress in the net zero transition" (PDF). OECD. 2021. Retrieved October 4, 2022.
  60. "At COP26, 11 National and Subnational Governments Launch The Beyond Oil & Gas Alliance" (PDF). Beyond oil and gas alliance. November 10, 2021. Retrieved January 4, 2021.
  61. "Who We Are". Beyond Oil and Gas Alliance. Retrieved January 4, 2022.
  62. Maierean, Andreea (August 16, 2021). "What went wrong? Fracking in Eastern Europe". Discover Energy – via SpringerLink.
  63. "Bulgaria Protesters Take to Streets Over New Environment Threat". Balkan Insight. 2020-06-26. Retrieved 2022-01-12.