Romania’s state-owned Hidroelectrica is preparing a major step into floating solar power, and this one is not just about putting panels on water. The company is testing the market for a Lower Olt River project that would pair floating photovoltaic parks with large battery systems on the banks, turning existing hydropower reservoirs into a cleaner and more flexible energy hub.
The key number is hard to ignore. The plan centers on about 90 MW of floating solar tied to five hydropower reservoirs, while Hidroelectrica’s own filings describe the wider Lower Olt development as 100 MWp of floating solar capacity with 200 MW and 800 MWh of battery storage.
In everyday terms, this is not a small add-on. It is a test of whether old hydropower infrastructure can become the backbone of a more modern renewable grid.
Solar panels on water
The project would use reservoirs linked to hydropower plants at Ipotești, Drăgănești, Frunzaru, Rusănești, and Izbiceni. Most of the planned floating parks would be sized at 20 MW, while Ipotești is treated differently because the 10 MW Nufărul pilot project is already moving forward there.
Why place solar panels on water in the first place? For the most part, it lets an energy company use space it already controls, without taking farmland or industrial land out of other uses. It also keeps the panels close to substations, grid connections, and hydropower staff who already know the site.
That last point matters. A floating solar park is not just a field of panels dropped onto a lake. It needs anchoring, electrical connections, monitoring, and a design that can handle changing water levels, wind, humidity, and day-to-day maintenance.
The Nufărul test
The pilot project, called “Nufărul,” is the starting point. Hidroelectrica signed with WALDEVAR Energy for a 10-MW floating photovoltaic system on the reservoir serving the Ipotești Hydroelectric Power Plant in Olt County. The contract was valued at about $8.7 million, excluding VAT, using current exchange rates.
The company says the pilot will use 620-W panels, 100-kW inverters, and four transformer stations to connect to the existing Ipotești hydropower substation. Estimated annual generation is about 13.4 GWh, which is modest on a national scale but important as a working model.
Think of it as a rehearsal before opening night. If the pilot works as expected, Hidroelectrica can repeat the concept across other hydropower reservoirs, learning how floating solar behaves in real conditions instead of only on paper.
The batteries are the real twist
The most interesting part may not be the panels, it is the storage. The Lower Olt plan includes battery systems with 200 MW of power and 800 MWh of capacity, enough for four hours of discharge at full output.
That storage is meant to help deal with one of renewable energy’s most familiar headaches. Solar and wind power do not always arrive when people need electricity most, so grids need flexible tools that can absorb power, release it later, and smooth sudden changes.
Hidroelectrica says the project is designed to help compensate for imbalances created by the rising share of renewable generation, provide technological services to the national power system, and reduce wear on hydropower plants that are currently used to balance those swings.
That sounds technical, but the idea is simple: use batteries for fast grid support, and avoid asking turbines to do every job.
Why hydropower companies are changing
For decades, Hidroelectrica’s strength has been water. It remains Romania’s largest green electricity producer, operating 188 hydropower plants and the Crucea wind farm, with about 6.4 GW of hydropower capacity plus 108 MW of wind capacity.
Climate change is making water less predictable, however. Dry years can squeeze hydropower output, while market volatility and solar peaks can make balancing the system more complicated. That is why floating solar and batteries are becoming more than a nice experiment.
By the company’s own explanation, the 2026 investment plan sets aside about $36.7 million for photovoltaic and storage projects, part of a broader move toward hybrid, flexible infrastructure. In practical terms, Hidroelectrica wants to keep the value of its dams and reservoirs while adding technologies that can work beside them.
A business move with environmental stakes
There is a business angle here, of course. Hidroelectrica is listed on the Bucharest Stock Exchange, majority-owned by the Romanian state, and under pressure to show that it can invest in the assets Romania’s grid will need over the next decade. Storage has become especially sensitive as more renewable power enters the system.
There is also an environmental angle. Floating solar can reduce pressure on land, use existing energy corridors, and make better use of reservoirs that are already part of the electricity system. Still, experts and regulators will have to watch local impacts carefully, including biodiversity, water quality, navigation, and maintenance activity around the lakes.
That is where the project becomes more than another clean-energy headline. If done well, it could show how countries with large hydropower fleets can add solar and storage without building everything from scratch. If done poorly, it could become another example of green infrastructure moving faster than environmental oversight.
What happens next
For now, the large Lower Olt project is still in preparation. The company is testing the contractor market and would later prepare the tender documents for the works needed, according to the project information reported in Romania.
That means there is still a difference between the Nufărul pilot, which has a signed execution contract, and the broader Lower Olt rollout, which is not yet fully contracted–a key detail. Big renewable announcements can sound final long before construction crews arrive.
Even so, the direction is clear. Hidroelectrica is trying to turn reservoirs into multi-use clean energy sites, where water, sunlight, and batteries work together. The trouble is, the grid needs that flexibility sooner rather than later.
The official market consultation was published on e-Licitatie.
