Sostanj power station

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Sostanj power station is an operating power station of at least 684-megawatts (MW) in Šoštanj, Slovenia with multiple units, some of which are not currently operating. It is also known as Šoštanj power station.

Location

Table 1: Project-level location details

Plant name	Location	Coordinates (WGS 84)
Sostanj power station	Šoštanj, Šoštanj, Slovenia	46.3723, 15.0534 (exact)

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Unit-level coordinates (WGS 84):

• PT 51, PT 52, PT 53, Unit 1, Unit 2, Unit 3, Unit 4, Unit 5, Unit 6: 46.3723, 15.0534

Project Details

Table 2: Unit-level details

Unit name	Status	Fuel(s)	Capacity (MW)	Technology	CHP	Start year	Retired year	Emergency/Backup
PT 51	Operating	fossil gas: natural gas	42	gas turbine	yes	2008	–	no
PT 52	Operating	fossil gas: natural gas	42	gas turbine	yes	2008	–	no
PT 53	Cancelled - inferred 4 y	fossil gas: natural gas	0	unknown	yes	–	–	no
Unit 1	Retired	coal: lignite	30	subcritical	–	1956	2010	no
Unit 2	Retired	coal: lignite	30	subcritical	–	1956	2008	no
Unit 3	Retired	coal: lignite	75	subcritical	–	1960	2014	no
Unit 4	Retired	coal: lignite	275	subcritical	–	1972	2018	no
Unit 5	Mothballed	coal: lignite	345	subcritical	yes	1977	2026 (planned)	no
Unit 6	Operating	coal: lignite	600	ultra-supercritical	yes	2015	2027 (planned)	no

CHP is an abbreviation for Combined Heat and Power. It is a technology that produces electricity and thermal energy at high efficiencies. Coal units track this information in the Captive Use section when known.

Table 3: Unit-level ownership and operator details

Unit name	Owner	Parent
PT 51	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
PT 52	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
PT 53	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
Unit 1	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
Unit 2	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
Unit 3	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
Unit 4	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
Unit 5	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]
Unit 6	Termoelektrarna Šoštanj doo [100%]	Holding Slovenske elektrarne doo [100.0%]

Project-level coal details

• Coal source(s): domestic

Ownership Tree

This ownership tree is part of the Global Energy Ownership Tracker, a project of Global Energy Monitor.

Background

Sostanj is the largest thermal power plant in Slovenia and produces electricity and heat using coal from the Velenje mine.

The power station comprises the following operating and retired generating units, which are referred to as:

• Unit 1 and Unit 2, both 25 MW, closed in 2010 and 2008 respectively;
• Unit 3, a 75 MW commissioned in 1960, closed in 2014;
• Unit 4, a 275 MW commissioned in 1972, and closed in July 2018;
• Unit 5, a 345 MW unit commissioned in 1977; it was reopened in August 2018 after almost three years of ecological rehabilitation works Unit 5 was subsequently placed in cold reserve in accordance with the Act on Transitional Financing of Accelerated and Fair Coal Phase-out (ZPFPPIP).
• Unit 6, a 600 MW unit commissioned in 2015
• PT 51, a 42 megawatt gas-fired unit commissioned in 2008 and nominally scheduled to run until 2027; and
• PT 52, a 42 megawatt gas-fired unit commissioned in 2008 and nominally scheduled to run until 2027.

In their 2020 'Integrated National Energy and Climate Plan of the Republic of Slovenia' submitted to the European Commission, Slovenia's government confirmed the closure of Unit 5 by 2030 and its replacement with a gas unit. At that time it appeared that Unit 6 would be much later, source referred to 2038 or 2042, another source mentioned 2054.

In January 2022, the Government of Slovenia adopted the National Strategy for a Coal Exit, defining 2033 as the year by which the coal phase-out would be completed.

In an October 2022 statement, the UN Special Rapporteur on Human Rights and the Environment stated: "the coal-fired power plant that provides approximately one-third of [Slovenia]’s electricity is not scheduled to be closed until 2033". As of September 2023, however, there were reportedly discussions of retiring the remaining coal units by 2029.

According to reporting from May 2024, Slovenia's Prime Minister had said that financial losses were likely to force the early closure of the remaining coal units at Sostanj. An ongoing analysis by Holding Slovenske Elektrarne (HSE), the state-owned utility, reportedly included options for closing or significantly reducing coal generation at the plant within the next three years. However, in June 2024, Slovenia’s latest draft of its 2030 energy and climate plan proposed an emissions reduction target of 55% by 2033, in line with a 2033 retirement date at Sostanj power station.

Under the emergency law adopted in December 2024, TEŠ was to primarily provide district heating for the Šalek valley (the municipalities of Velenje and Šoštanj) through April 2027, after which operations were expected to cease. Approximately €324 million was allocated to support heat production during this transitional period, with a further €79 million set aside to repay the plant's outstanding loans.

As of September 2024, HSE's Sostanj operations were projected to face bankruptcy in January 2025. The coal-fired power station and nearby Velenje Coal Mine would reportedly generate 150 to 200 million euros of losses in the next year. According to reporting from December 2024, the Slovenian government had agreed to pay €403 million (US$424 million) to take over the Sostanj power station and associated Velenje Coal Mine from HSE. The coal plant was primarily slated to provide district heating for the Salek Valley until April 2027 at a cost of €327 million (US$344 million).

In early 2025, TEŠ began selling its electricity independently on the market, as HSE ceased to act as its electricity sales agent. The first four months of 2025 proved commercially successful: the plant sold 1,045 GWh of electricity, generating revenues of €138 million, €29 million above plan.

In January 2025, Unit 5 was transferred to cold reserve under Slovenia's Act on Transitional Financing of Accelerated and Fair Coal Phase-out (ZPFPPIP), with permanent shutdown planned for June 2026.

Ownership

The power station is owned by Termoelektrarna Sostanj (TEŠ).

On 28 March 2025, a new act establishing TEŠ as an independent company entered into force, transferring it from HSE to the Slovenian Sovereign Holding (SSH).

Coal supply

The power station consumes "between 3.5 and 4.2 million tonnes" of lignite a year, approximately 90% of all the coal produced in the country. Coal for the power station is sourced from the nearby Velenje mine.

Gas Units

Two gas units PT 51 and PT 52 have been in operation since 2008.

In their 2020 'Integrated National Energy and Climate Plan of the Republic of Slovenia' submitted to the European Commission, Slovenia's government confirmed the closure of coal unit 5 by 2030 and its replacement with gas units.

Unit 6

A new 600 megawatt (MW) coal-fired power station (Unit 6) was proposed to "replace obsolete facilities" at the existing plant. The project would replace the power plant’s existing units 3-4 and possibly unit 5.

Unit 6 was synchronized in 2014, and planned for operation in April 2015. Unit 6 was planned to replace Unit 3. The 275MW Unit 4 was planned to be decommissioned in December 2015.

A planned overhaul of Unit 6 commenced on 22 April 2025 and was expected to be completed by 20 June, but was extended until early July due to delays in the delivery of components. A restart was planned for the end of September 2025, when demand for district heating was expected to rise.You said: Unit 1 and Unit 2, both 25 MW, closed in 2010 and 2008 respectively;

Cost and Funding for Unit 6

Since initial project proposal, costs have risen from EUR 700-900 million to EUR 1.2 billion. Permits were also need to be purchased by Slovenia as part of the EU Emissions Trading Scheme. The project received permissions from the Slovenian authorities.

In January 2011, a financing agreement for the project was closed. US$971.25 million in loans was provided by European Bank for Reconstruction and Development, Helaba, Societe Generale, Bankia, UniCredit, and Kommunalkredit Austria. The project also received a US$667,401,143 loan from the European Investment Bank.

Corruption allegations

In July 2012, the European Anti-Fraud Office (OLAF) decided to start an official investigation into the Sostanj plant due to charges of corruption (bribery and money laundering) and conflicts of interests in the granting of the contract to the company Alstom.

In October 2014, Slovenian police charged 10 people associated with the project of defrauding electricity consumers of an estimated €284 million (US$333 million).

In May 2018, leaked details of a Slovenian police investigation into Alstom’s €1.4 billion (US$1.6 billion) 600 MW expansion of the Sostanj plant found that it was €500 million (US$586 million) more expensive than equivalent plants the company built elsewhere (the expansion was originally estimated to cost €700 million, or US$820 million). A Slovenian TV station alleges that documents obtained as part of the investigation indicate Alstom allocated €3 million (US$3.5 million) for kickbacks associated with the project.

In May 2020, after several years of uncertainty over the status of the investigation, Slovene prosecutors filed charges including money laundering against 12 people and two companies. Unofficial information reported by the media suggests that the two companies are Slovenia’s Sol Intercontinental and France’s Alstom Power.

In October 2022, the Celje District Court ordered General Electric to pay a €23 million (US$22.7 million) fine over the alleged bribery scheme associated with the construction of the power station's Unit 6.

Opposition

On January 17, 2012, representatives from the Focus Association for Sustainable Development, Environmental Legal Service, and CEE Bankwatch Network filed a complaint regarding the Sostanj Thermal Power Plant in Slovenia. Addressed to Anoush Begoyan of the European Bank for Reconstruction and Development, the complaint emphasized how the power plant threatened to perpetuate CO2 emissions and contribute to dangerous global climate change.

In April 2014, the CEE Bankwatch Network released an article on how the Sostanj power plant will significantly increase EU’s global carbon emissions. They also questioned the economic viability of the project, in conjunction with Slovene ministers and other experts, along with corruption issues in the production of the power plant.

Carbon Emissions

In 2012, it was estimated that operating Unit 6 would result in emissions of 3.4 mega tonnes of CO2 per year, which is equivalent to almost all of Slovenia’s allowable emissions in 2050.

2025-2027

In 2025, TEŠ shifted its primary focus to heat supply, with electricity sold as a byproduct. Unit 6, the plant's 600 MW main coal-fired unit, underwent an overhaul beginning in April 2025; although the overhaul was expected to be completed in July, the unit was not planned to restart until late September, when heat demand was expected to rise.

On April 10, 2026, Unit 6 went offline after a generator disturbance caused increased turbine vibrations and triggered an automatic shutdown, one day before the unit’s scheduled seasonal shutdown. TEŠ said Unit 6 was expected to remain offline until around mid-September 2026, while heat supply would be maintained using gas turbines.

Financing

• Source of financing: Unit 6 - US$971.25 million in debt from European Bank for Reconstruction and Development, Helaba, Societe Generale, Bankia, UniCredit, and Kommunalkredit Austria; US$667,401,143 in debt from the European Investment Bank.

Groups campaigning against the proposed expansion

• Bankwatch (Czech Republic)
• Focus Association for Sustainable Development (Slovenia)

Articles and Resources

Additional data

To access additional data, including interactive maps of the power stations, downloadable datasets, and summary data, please visit the Global Coal Plant Tracker and the Global Oil and Gas Plant Tracker on the Global Energy Monitor website.