Source: pv magazine

The battery energy storage system is the first phase of a 315 MW/760 MWh system that is being developed alongside 238 MW of solar under Bulgaria’s largest hybrid power project to date, due for completion next year.

By Patrick Jowett

Oct 14, 2025

Vienna-based independent power producer Renalfa IPP has commissioned the first phase of a large-scale battery energy storage system (BESS) in Bulgaria.

The company has brought online 65 MW/260 MWh of a planned 315 MW/760 MWh battery energy storage system (BESS) as part of the Tenevo Hybrid Renewable Project.

Located in southeastern Bulgaria, the hybrid project is being developed by Tenevo Solar Technology, a joint venture company between Renalfa IPP and Danish developer Eurowind Energy. Chinese energy storage company Hithium and Chinese power solutions provider Kehua are supplying the BESS technology, while Bulgarian developer Solarpro is acting as project manager.

Once completed, the Tenevo project will encompass a 238 MW solar site alongside the 315 MW/760 MWh BESS and 250 MW of wind turbines, making it Bulgaria’s largest and most complex hybrid energy storage project to date. It is due for completion early next year.

The project is financed by The European Bank for Reconstruction and Development and Raiffeisen Bank International AG.

In August, Eurowind Energy announced the first 69 MW of the 238 MW solar farm had come online.

According to a statement from Renalfa, the first phase of the BESS is already one of the largest co-located battery storage systems in Europe and takes its energy storage capacity in operation to in excess of 1 GWh.

The company, which is active in Bulgaria, Hungary, North Macedonia and Romania, also claims to have over 1 GW of projects in the late stages of development, as well as a wider project pipeline in excess of 4 GW.

Bulgaria inaugurated a 124 MW/496.2 MWh BESS in May, billed as the largest in the European Union to date. The country’s Ministry of Energy has since launched a public consultation on a new subsidy program targeting 1.9 GWh of standalone storage capacity.

CENSA Upcoming Events:

1. Dec.4-5 | 2025 China Energy Storage CEO Summit | Xiamen, Fujian

2. Apr. 1-3, 2026 | The 14th Energy Storage International Conference & Expo

On 8 September, the world's first 400MWh energy storage power station based on 628Ah large energy storage batteries achieved successful one-time power delivery.

Located in Lingxiu County, Shijiazhuang, east of the Taihang Mountains, the 200MW/400MWh stand-alone energy storage station has officially begun operation. This marks the world's first large-scale deployment of a 600Ah+ large energy storage battery in a 100MWh project, signifying that the energy storage industry has entered the era of “2 kWh per battery cell”.

Storage project at Hebei, with EVE 628Ah+ Cell

Large batteries are widely regarded as the key pathway to reducing the levelized cost of storage (LCOS). By increasing single-cell capacity and reducing system integration complexity, these batteries can significantly lower the total lifecycle cost of energy storage systems. In 2024, global energy storage shipments surpassed 300 GWh, marking the final sprint before the industry enters the TWh era. As policy subsidies gradually phase out, market competition now increasingly depends on technological strength and product performance.

EVE Energy has achieved three major technological leaps in the large energy storage battery sector - from concept unveiling to mass production and pioneering engineering applications - driving the industry into a new phase of high-quality development fueled by innovation. In October 2022, the company introduced the LF560K concept large energy storage battery, ushering in the “500Ah+” era. In January 2024, it globally premiered the 628Ah “Mr. Big” large energy storage battery, achieving a single-cell energy capacity exceeding 2 kWh. By September 2025, EVE commissioned the world’s first 400MWh-scale power station using these batteries, transitioning from lab to grid in just 20 months.

The value of large energy storage batteries is backed by solid data. Operational data from the Jingmen demonstration project in Hubei Province showed system energy efficiency consistently above 95.5%, while maintenance components were reduced by 50% and operational costs lowered by 30%. In July 2025, EVE’s 600Ah+ battery became the world’s first to be fully certified under China's new national standards. The following month, the company secured a 154MWh order from China Electrical Equipment Group - the world’s first commercial order for 600Ah+ large energy storage batteries.

Behind this technological leadership lies EVE’s philosophy of “long-termism”. Chairman Liu Jincheng emphasizes, “A battery is a living entity. We approach each one with reverence, ensuring every cell is crafted to perfection.” This reverence for technology is reflected in the company's sustained R&D investment: the company’s sustained R&D commitment is reflected in its team of over 6,000 researchers, cumulative R&D investment exceeding RMB 10 billion since 2020, more than 10,000 patents, and involvement in 25 national-level projects. At its 60GWh super factory in Jingmen, extreme manufacturing principles enable production of 1.5 batteries per second with defect rates controlled at the PPB level, ensuring exceptional consistency and reliability.

With production bases advancing in Malaysia and Hungary, EVE Energy continues to optimize its global capacity layout. The company aims to reach 328GWh production capacity by 2027, supporting the worldwide energy transition. It has established deep partnerships with leading enterprises such as State Grid, China Southern Power Grid, Huaneng, Huawei, and Sungrow, while also making breakthroughs in overseas markets including Australia.

Industry analysis indicates that the first half of 2026 will witness a concentrated release of 500Ah+ batteries. Through its Lingshou project, EVE Energy demonstrates that large batteries are not a future concept but an ongoing reality. The deployment of this world-first 600Ah+ energy storage power station is not only a technological milestone but also an industry signal: the era of large batteries for energy storage has arrived.

CENSA Upcoming Events:

1. Dec.4-5 | 2025 China Energy Storage CEO Summit | Xiamen, Fujian

2. Apr. 1-3, 2026 | The 14th Energy Storage International Conference & Expo

Renalfa switches on 260 MWh battery storage system in Bulgaria

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The World’s First 600Ah+ Large Energy Storage Battery Project Successfully Delivers Power

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