IN Brief:
- WALDEVAR is delivering 95MWp of solar generation and 220MWh of battery storage for SANY at Dobrești.
- Electrical infrastructure includes a 110/20kV transformer substation and a 110kV underground connection.
- The solar plant is expected to generate around 135GWh annually, with storage providing energy shifting and balancing capability.
WALDEVAR Holding is delivering a combined solar, battery storage, and high-voltage infrastructure project for SANY Group at Dobrești in Romania’s Dolj County.
The development comprises 95MWp of photovoltaic capacity and 220MWh of battery energy storage, together with a 110/20kV transformer substation and a 110kV underground line providing the high-voltage connection infrastructure.
WALDEVAR distributed detailed project information on 25 and 26 August, although the symbolic inauguration at the Dobrești site took place on 14 August. The current disclosure therefore provides new engineering detail around a project whose ceremonial construction milestone predates the normal sourcing window.
The developer estimates annual photovoltaic production of approximately 135GWh. The BESS is intended to shift part of that generation beyond daylight hours and provide grid balancing capability, although its power rating has not been disclosed.
Without an MW specification, the battery’s nominal discharge duration cannot be calculated. A 220MWh energy capacity can support markedly different operating profiles depending on the inverter rating and grid connection allocated to the storage system.
High-voltage infrastructure ties the hybrid plant together
The 110/20kV substation is central to the electrical architecture rather than an ancillary project item. Power collected from the solar and battery systems at medium voltage must pass through transformation, protection, metering, control, and switching equipment before it can enter the 110kV network.
The battery makes those power flows bidirectional. Solar production and battery discharge both send electricity towards the grid, while charging can turn the storage system into a large controllable load. Protection and connection studies therefore need to account for operating conditions on both sides of zero export.
The underground 110kV line adds a further set of design requirements. Cable thermal capacity, reactive behaviour, protection settings, termination equipment, route conditions, and the capability of the receiving network will all influence the maximum power that can be transferred from the site.
Those limits cannot be derived from the 95MWp solar figure or 220MWh storage figure alone. The eventual export and import capability depends on the connection agreement, transformer ratings, inverter configuration, network studies, and any operating restrictions imposed at the point of connection.
Hybrid operation can nevertheless make greater use of fixed electrical infrastructure. Solar output rises and falls through the day, leaving spare transformer and connection capacity outside the strongest generation periods. Storage can move some energy into those periods rather than allowing the connection to remain lightly used.
The same battery can also absorb solar production when export capacity or electricity prices make immediate delivery unattractive. That requires sufficient charging power and available state of charge at the moment the excess generation occurs.
A full battery provides no further absorption capacity, while a battery held partly empty for potential solar charging may have to forgo another market opportunity. Dispatch therefore requires coordination between forecast photovoltaic production, state of charge, grid limits, and balancing commitments.
Round-trip efficiency also means the battery cannot shift energy without loss. Electricity stored during the day must usually gain enough later value to compensate for conversion losses, battery degradation, and the cost of operating the complete storage system.
WALDEVAR’s scope is particularly relevant because the company has expanded beyond photovoltaic EPC into high-voltage infrastructure. Its current business includes substations and grid-related engineering alongside solar construction, allowing more of the plant and connection interfaces to sit within one delivery organisation.
That can reduce contractual fragmentation, although equipment from different manufacturers still has to be coordinated. Solar inverters, battery controls, power conversion systems, transformers, switchgear, protection relays, SCADA, communications, and utility interfaces must exchange consistent information before the hybrid site can be commissioned safely.
SANY enters the development from a wider industrial equipment base that has expanded into renewable energy. The Dobrești project places it on the asset side of a Romanian market where solar pipelines are increasingly being accompanied by storage and dedicated high-voltage works.
Romania’s connection challenge is becoming more pronounced as individual renewable developments increase in scale. A project approaching 100MW of solar and carrying 220MWh of storage is large enough for the grid connection to be a substantial engineering package, rather than an extension designed after the generation plant itself.
No commercial operation date or BESS power rating has been disclosed in the material currently available. Those remain important omissions because they determine both the delivery timetable and the range of storage services the project can provide.
The published specifications are sufficient to define the physical scope: 95MWp of solar, 220MWh of storage, a 110/20kV substation, and a dedicated underground 110kV connection. Delivery will now depend on those elements being commissioned as one electrical system rather than four separate construction packages.
