Greek industrial and energy group Metlen has acquired local energy software developer Joule to enhance its management and commercial optimization of renewable energy portfolios.
Financial terms of the transaction were not disclosed by the companies. At the heart of the agreement is jHub, a platform developed by Joule that functions as a Virtual Power Plant to provide remote supervision, control, and optimization of renewable energy projects and storage facilities.
The jHub system integrates solar and wind power installations, electric vehicle charging stations, and energy demand loads, while also supporting energy storage systems. Metlen's Cumulative Representation Entity currently manages about 1,450 renewable energy stations with a total installed capacity of 3 gigawatts across all main renewable technologies.
Metlen recently added its first two energy storage stations, with a total capacity of 378 megawatts, to its portfolio. Outside Greece, Metlen provides producer representation services in Italy and Romania, and is in the process of expanding into Bulgaria.
Metlen told Capital.gr that Joule's existing team remains a key pillar of the investment and will be retained to support product development, engineering, and commercial expansion. Metlen added that the team will be reinforced through access to Metlen's resources, international network, and industry experience.
The acquisition aims to further develop jHub into an integrated energy management platform with new features for energy storage, hybrid renewable and storage portfolios, and advanced energy flexibility services. The integration will also support Metlen's international energy operations.
Strategic rationale and market challenges
Metlen stated to Capital.gr that the acquisition represents a strategic step in its broader digital transformation. The company noted that jHub brings real-time monitoring, forecasting, and control capabilities for renewable and storage assets to improve operational efficiency.
Virtual Power Plants aggregate decentralized energy sources into a single network to operate like a traditional power station. Demand for such continuous management is growing in Greece as renewable energy producers face increasingly complex market conditions, including frequent generation curtailments and periods of negative electricity prices.
Metlen highlighted that integrating jHub gives the group technological autonomy in a critical operational area. Joule's technology will also serve as a foundation for new digital services covering energy storage systems, dispatchable renewable units, and hybrid power plants.
Joule founding team and corporate history
Joule was established in June 2020 with 60,000 euros of self-funded equity capital. The company was co-founded by Giorgos Papatheodorou, an electrical and computer engineer from the National Technical University of Athens, Christoforos Karadimas, a sociologist from the American College of Greece, and Spyros Michas, a developer and economist from the Athens University of Economics and Business.
All three co-founders were named to the Forbes 30 Under 30 Greece list in 2024 for their work in energy and technology. Joule specializes in software and services for energy and electric mobility, centered on its flagship jHub platform.
The jHub platform links technical management with energy market participation to maximize operational availability and financial returns. It handles revenue optimization through optimal buying, selling, and storage of energy based on market conditions, while performing remote monitoring and technical control for individual and aggregated units.
Joule also develops artificial intelligence and business intelligence tools to assist renewable energy producers in energy markets. In electric mobility, the company offers the jCharge application for drivers to locate and charge vehicles, alongside the jPanel platform for station owners to manage charging networks. Additionally, Joule designs strategies and automated software for residential and utility-scale energy storage systems.
According to Joule's 2024 financial statements, the company generated revenue of 86,800 euros in 2024, up from 11,300 euros in 2023. The company recorded an after-tax loss of 231,400 euros in 2024, compared to a net loss of 193,400 euros in 2023.
Technical operations and market integration
In practical applications, jHub records and analyzes more than 50 distinct signals from each inverter, combining them with data from relays, weather conditions, and the Hellenic Electricity Distribution Network Operator, known as DEDDIE. This multi-source analysis allows the platform to detect systematic equipment faults and real-time operational failures.
Producers receive live alerts and reports with customizable thresholds for fault detection. Maintenance crews can utilize live visual maps of generation stations to locate specific problematic strings or inverters, monitor repair activities, and track resolution times and spare parts usage.
Joule developed specialized software for aggregators that incorporates neural networks to refine production forecasting and provide updates on station availability. The software connects directly to the Hellenic Energy Exchange for automated bid submission and live market data retrieval. According to Joule, jHub is currently utilized by more than 100 companies across the Greek renewable energy market.
