Turkish company YEO, active in the renewable energy sector in Romania, will open an energy storage battery factory in Istanbul in September. The announcement was made by Atılay Koyaș, Director of Development and Sales for Storage Systems (BESS) at YEO, at the 11th Energy Strategy Summit, the flagship event of Energynomics.
“Construction is finalised and we will start production in September. It is a strategic project for us, which comes at a time when the demand for storage solutions is growing at an accelerated pace,” explained Atılay Koyaș, adding that YEO aims to become a major provider of BESS solutions for residential and commercial projects as well as for industrial and network-wide applications.
Regional expansion and vertical integration
YEO is already present on the Romanian market through photovoltaic projects developed together with Shanghai Electric Power (SEP), in a partnership that involved investments of €65.8 million in two solar power plants with a total capacity of 129 MW. Subsequently, 75% of the shares in the project vehicles were transferred to SEP, with the approval of the Romanian authorities.
The new battery production facility is part of the company’s expansion strategy, which aims to reach a global capacity of 1 GW in renewable energy and another 1 GW in storage systems by 2030. “This is a natural vertical integration – from EPC to BESS solutions manufacturer – which allows us to offer our partners complete solutions, adapted to the new requirements of the energy transition,” Koyaș said.
Batteries – from household to transport networks
In his speech, Atılay Koyaș gave a detailed technical overview of storage systems, explaining the differences between configurations for residential use, commercial applications and containerised systems for utilities. “It all starts from the cell – the basic unit. Through series and parallel connections, we end up with complete modules, racks and containers, depending on the application,” he explained.
DOWNLOAD THE PRESENTATION OF ATILAY KOYAȘ
BESS solutions can be used together with solar or wind power plants, but also as stand-alone systems connected directly to the transmission grid. Koyas gave the example of a 500 MW project that YEO is developing in Azerbaijan at the 400 kV grid level. In parallel, applications for microgrids, data centres, electric vehicle charging stations or industry are rapidly diversifying.
Arbitration, stability and ancillary services
An important part of his speech focussed on the economic functions of BESS systems. Starting from the data of the Romanian spot market for the years 2023-2025, Koyaș explained how batteries enable smart arbitrage – charging at off-peak hours and discharging at peak consumption. This behaviour is becoming essential in a market characterised by what is known as the “duck curve” – very low prices at midday and very high prices in the evening and morning.
“A solar producer without a storage system will sell at rock-bottom prices during peak production hours. The solution is clear: integrate batteries to make the most efficient use of the energy produced,” Koyas emphasised.
In addition to arbitrage, batteries can also provide ancillary services such as frequency regulation, black start capability or grid balancing support. Depending on the configuration, the same unit can be split between several functions – for example, 50 per cent for arbitrage and 50 per cent for participation in system services.
Key parameters for performance and durability
At the end of the presentation, Koyas reviewed the main technical indicators that define the performance of storage systems: depth of discharge (DOD), state of charge (SOC), state of health (SOH), duty cycles and C-rate (charge/discharge rate). These characteristics are essential for configuring an efficient system tailored to the application requirements.
A topical example is the requirement in Turkey to use 1C rate BESS systems in all new wind and solar projects – a model that Koyaș says could be relevant for other markets in the region, including Romania.
For all inquiries related to the Romanian market, Kazım Erdem Demirel – the executive in charge of YEO’s operations in Romania – can be contacted.
2025 Energy Strategy Summit was organised by Energynomics, with the support of our partners: AJ Brand, Elektra Renewable Support, ABB, Adrem Asset Management, Alive Capital, BCR, DEKRA, Distribuție Energie Electrică Romania, E-Infra, Eaton Electric, Electrica Furnizare, EnergoBit, Enery, Enevo Group, Enexus, European Investment Bank, Evryo, Exim Banca Romaneasca, Delgaz Grid, Genesis Biopartner, Huawei, ING Bank, Jantzen Renewables, Keno Energy, Leader Team, LONGi, Nano Energies, Prime Batteries Technology, Procesio, Procredit Bank, Relians, Renomia, Romgaz, Schneider Electric, script.ai, Sermatec, smartPulse, Solar Today, SolaX, Think Blu Solution, Voltika, Wiren, YEO, AIployees, Aqua Carpatica, Alexandrion, Carbon Tool, Imsol.