/ATHENS, GREECE, November 3, 2025, 10:00 CET, RENEWABLE MARKET WATCH™/
Mantasia Energy has received approval from the Greek Ministry of Energy and Mineral Resources to double the green hydrogen production capacity at its flagship hybrid renewable project near Kara Hassan (Mantasia), Domokos. The permitted upgrade increases the electrolyser unit from 50 MW to 100 MW, as confirmed by official sources and sector report information from Newmoney, Greece.
According to the General Directorate of Environmental Policy, the principal change in the environmental permit involves scaling the green hydrogen facility to a nominal capacity of 100 MW. The revised layout comprises 10 individual electrolysis systems, each rated at 10 MW, all co-located within the project’s designated industrial zone.
Environmental impact assessments indicate that this capacity enhancement introduces no significant incremental emissions—air, solid or liquid waste, or noise—during construction or operation, maintaining compliance with national regulatory standards and sustainability criteria.
Project Scope and Technical Details
The overall development encompasses a 251.904 MW photovoltaic (PV) power station integrated with a 100 MW green hydrogen unit, situated at “Kara Hassan” in the Domokos municipality, Fthiotida, covering approximately 4.27 million square metres. The majority of construction will take place within the Local Community of Fyliadonos, with a minor portion extending into the Mantasia area.
Key infrastructure includes:
1. A utility-scale PV plant with 251.904 MWp installed capacity
2. A 400/33 kV High Voltage Center (HVC) with 600 MVA capacity for grid integration—accommodating future projects
3. A 100 MW PEM-electrolysis green hydrogen facility
The buildout involves installation of 475,272 monocrystalline silicon PV modules, 144 photovoltaic cells (530 Wp each), 708 DC combiner boxes, and 48 Sunny Central 4600 UP inverters. Planned supporting infrastructure features medium voltage substation buildings, voltage step-up transformers, grounding, and lightning protection systems.
Hydrogen production will be realised with the new 10 x 10 MW electrolysis units, occupying an 11,025 sq.m. site within the broader PV installation zone. Hydrogen storage is configured as a modular centralised system using seamless steel cylindrical tanks, providing up to 40 tonnes of storage capacity. For export to Greece’s high-voltage grid (E.S.M.I.E.), a new 400/33 kV substation will be constructed at “Kantalio,” Achladia, spanning 73,672 sq.m. beneath an existing 400 kV transmission corridor.
This project exemplifies the rapid evolution of Greece’s renewable energy sector, integrating large-scale solar PV with advanced green hydrogen technologies to support national and European decarbonisation objectives.
The company and the course of the project
The project was initially promoted by the German group Altus AG, which in May 2020 established the company “Ilos New Energy Greece”. At the same time, in December 2020, the company “Mantasia Energy IKE” was also established. It is noted that Altus, a subsidiary of Kraftwerke Mainz-Wiesbaden AG (KMW ), together with Omnes Capital, has created the separate corporate arm of “ILOS GR INVEST GmbH” specifically for the solar energy sector.
The German group, headquartered in Karlsruhe, which covers the entire spectrum of RES, received in 2021, through “Ilos New Energy Greece”, a producer certificate for a photovoltaic power generation plant, with an installed capacity of 251.904 MW and a maximum production capacity of 251.904 MW, at the location of Longos, in the Municipal Unit of Domokos in Fthiotida.
In June 2022, the company submitted to RAEYS an application to amend the producer certificate regarding the reduction of the photovoltaic plant installation site boundaries. Subsequently, there were changes at the shareholder level of “Mantasia Energy IKE” as “ILOS GR INVEST GmbH” retained 50%, with 49% being acquired by the German Yamko Energy and 1% by the manager in our country, Mr. Sp. Koutroubas.
Based on an amendment and rewording of the AEPO issued on March 28, 2022, a 251.904 MW photovoltaic power plant of Mantasia Energy is planned at the Mantasia location in the Municipality of Domokos, and in addition, the installation and operation of a Hydrogen Production Unit with a nominal power of 50 MW, as an accompanying project. The new amendment issued on October 27, 2025, provides for a change in the type of green hydrogen production unit by increasing its nominal power from 50 MW to 100 MW.
For more information and answers to your questions about the Greek and the Western Balkans solar power market and related content, you may read here: Western Balkans Solar Photovoltaic (PV) Market Outlook 2025 ÷ 2034
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