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Renalfa IPP starts operating Bulgaria’s largest BESS project with Hithium/Kehua tech


A 25MW/55MWh battery energy storage system (BESS) has been commissioned in Bulgaria, Eastern Europe, by operator Renalfa IPP, using technology provided by Chinese firms Hithium and Kehua.

The project is co-located with a 33MWp PV plant in southwestern Bulgarian city of Razlog and is connected to the transmission system operator (TSO) grid.

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The BESS will shift the renewable generation to the evening hours and trade energy on the market, and the trading and optimisation service will be provided by utility KER Toki Power. Its stored energy will be played into the capacity and balancing markets, and participate in pan-European ancillary services markets including aFFR and mFFR frequency response grid services.

Austria-headquartered Renalfa IPP is a joint venture between a subsidiary of engineering procurement and construction (EPC) and operation and maintenance (O&M) firm Solarpro Holding and French infrastructure investor RGreen Invest.

The BESS technology was provided by energy storage-focused lithium-ion OEM and BESS firm Hithium and power solutions firm Kehua Tech, both based in China. Hithium won the contract back in November last year, as reported by at the time.

Nick Antonov, spokesperson for Renalfa IPP, said: “This co-located utility scale battery marks the start of hybridisation of our over 1GW portfolio of renewable assets in operation and in construction. We are about to introduce similar solutions in the other wind and PV assets in the region, including Hungary and Romania.”

“The main goal is to fully mitigate the PV profile risk of the generators. In the wider context of the energy transition, this facility demonstrates how advancements in technology are making renewable generation far more useful, dispatchable and flexible to supply and demand,” Antonov said.

It comes after local news outlets reported that another independent power producer (IPP) Vinali Re submitted plans for a hybrid wind, solar and storage project near Dobrich in northeastern Bulgaria.

In March, the country’s Ministry of Energy launched tenders for around 1,425MW of renewable generation projects along with 350MW of BESS.

The Renalfa IPP project in Razlog has been claimed as the biggest project of its type in Bulgaria. It is also larger than the biggest project to come online so far in neighbouring Romania, a 6MW/24MWh BESS in that country’s Constanta County, co-located with solar PV and wind generation plants. That project, by developer Monsson Group and system integrator Prime Batteries Technology was notable in that battery equipment and system integration was provided by Prime Batteries.

Marcin Wasilewski, CEO of the European Institute of Innovation & Technology (EIT) InnoEnergy in Central and Eastern Europe claimed the Constanta project was proof European ESS and battery companies could “successfully challenge their Asian and global competitors,” while Prime Batteries CEO Vicentiu Ciobanu said the project would be expanded to 215MWh capacity next year.

Monsson’s head of M&A, Sebastian Enache, and energy storage project manager, Mihaela Popescu spoke to Premium about the Romania project for an interview published in May.

Meanwhile, Renalfa IPP’s portfolio and pipeline of wind, solar and BESS projects in development, construction and operation in Bulgaria, Romania,, Hungary, and North Macedonia totals roughly 2GW, with 455MW in operation and over 550MW in construction.’ publisher Solar Media will host the 2nd Energy Storage Summit Central Eastern Europe on 24-25 September this year in Warsaw, Poland. This event will bring together the region’s leading investors, policymakers, developers, utilities, energy buyers and service providers all in one place, as the region readies itself for storage to take off. Visit the official site for more info.

24 September 2024
Warsaw, Poland
If your goal is to meet other industry professionals and create valuable business partnerships to better understand the region, then the Energy Storage Summit Central Eastern Europe 2024 is the right place for you. We provide the perfect platform to make high-level connections and fuel enriching and beneficial conversations in a relaxed yet professional environment. Our networking opportunities have been described as second to none by industry professionals.
8 October 2024
San Francisco Bay Area, USA
PV Tech has been running an annual PV CellTech Conference since 2016. PV CellTech USA, on 8-9 October 2024 is our second PV CellTech conference dedicated to the U.S. manufacturing sector. The event in 2023 was a sell out success and 2024 will once again gather the key stakeholders from PV manufacturing, equipment/materials, policy-making and strategy, capital equipment investment and all interested downstream channels and third-party entities. The goal is simple: to map out PV manufacturing in the U.S. out to 2030 and beyond.
12 November 2024
San Diego, USA
As we see more storage projects become operational, the big question is “how to maximize your assets?” This event will prepare the industry for the road ahead, looking at the core fundamentals of asset management, understanding operational challenges, along with the latest optimization and software development. You can expect to meet and network with all the key industry players from major US asset owners, operators, RTOs and ISOs, optimizers, software and analytics providers, technical consultancies, O&M technology providers and more.
17 June 2025
Napa, USA
PV Tech has been running PV ModuleTech Conferences since 2017. PV ModuleTech USA, on 17-18 June 2025, will be our fourth PV ModulelTech conference dedicated to the U.S. utility scale solar sector. The event will gather the key stakeholders from solar developers, solar asset owners and investors, PV manufacturing, policy-making and and all interested downstream channels and third-party entities. The goal is simple: to map out the PV module supply channels to the U.S. out to 2026 and beyond.

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