On the right bank of the Danube River, the rock layers that have been dormant for many years are about to be awakened. Serbia and Romania have joined hands across the river to turn the ancient waterway into an energy link. On this land that has witnessed hydraulic miracles, a new regulating hub is breaking through the water, providing a powerful stabilizer for the green pulse of the Balkan Peninsula.

The two countries signed a contract to launch a new project

On July 16, 2026, the governments of Serbia and Romania signed a memorandum of understanding on cooperation for the Danube Iron Gate 3 large-scale pumped storage power station. Dubravka Jedovi ć Handanovic, Minister of Mining and Energy of Serbia, and Ili Boloyan, Acting Prime Minister and Minister of Energy of Romania, jointly signed this official bilateral document, marking the substantive docking stage of the cross-border energy project, and the cooperation is promoted based on the existing Danube River water cooperation mechanism between the two sides.

The Iron Gate No. 3 pumped storage station planned in the memorandum is located on the right bank of the Danube River, upstream of the existing Iron Gate No. 1 hydropower station. The project's radiation range spans across two countries, and both sides will form a joint working group to regularly exchange engineering technical information and various survey data.

Serbia and Romania have long jointly managed two mature cross-border hydropower stations, Iron Gate 1 and 2, on the Danube River. Romania has set a bottom line for cooperation on new projects. Acting Prime Minister Boloyan stated that the construction of the project must not interfere with the stable operation of the two old power plants, and that ecological protection along the coast of Romania and Bulgaria should be carried out simultaneously, taking into account the needs of navigation and passage on the Danube River. Serbia plans to complete the national spatial planning and complete the technical proposal preparation for the Iron Gate 3 project within 2026.

International framework supports project advancement

In terms of funding and technology, the Iron Gate 3 project has mature international cooperation support and is the first demonstration project to be implemented under the US Serbia bilateral energy government agreement. The US Embassy in Serbia previously issued a notice for soliciting project cooperation intentions globally, and six international companies have submitted their cooperation intentions. The relevant application materials are currently being reviewed and evaluated.

In terms of cross-border power interconnection, the 400 kV cross-border transmission line connecting Ressica, Romania and Panchevo, Serbia has a total length of 131 kilometers, of which 63 kilometers are located within Romania. This line has been officially put into commercial use in early 2025. The two countries plan to rely on existing transmission channels to further open up the bilateral electricity market and deepen energy trading linkage.

The value of regional energy transformation is highlighted

From the perspective of project scale and industry impact, the construction of Tiemen No. 3 pumped storage power station will comprehensively change the development pattern of the energy industry in the Balkans and Eastern Europe. The planned installed capacity of the project is 2400 megawatts, with a supporting capacity of 400 megawatts for wind and solar new energy grid connection. Pumped storage is currently a mature high-capacity physical energy storage solution, which can provide peak shaving and frequency regulation support for the rapid expansion of clean energy in the region after completion, and optimize the local power grid regulation capacity.

The overall estimated investment for the project is 2.63 billion euros, and it is expected to be completed and put into operation by 2038. The construction period of more than ten years, combined with large capital investment, will drive the upstream and downstream procurement of water conservancy projects, reversible hydropower units, and high-voltage transmission and transformation equipment, reshaping the Balkan energy supporting industry chain. Relying on the stable transmission capacity of the Rexhica Panchevo high-voltage line, the joint development of Tiemen No. 3 will force the two countries to unify cross-border transmission quotas, power grid dispatch standards, and electricity spot trading rules, while synchronously improving software and hardware, accelerating the integration of regional cross-border electricity markets. Keywords: Serbia, Romania, pumped storage

From the commissioning of cross-border high-voltage transmission lines to the implementation of the memorandum of cooperation on the Tiemen 3 energy storage power station, Serbia and Romania's energy cooperation along the Danube River has comprehensively moved towards a deep stage of cooperation in the construction of large capacity energy storage and the interconnection of electricity markets. The project construction needs to take into account multiple constraints such as existing water conservancy facilities and river navigation. This cross-border collaborative development model is an important reference for observing the progress of green energy transformation in Eastern Europe and the potential for cross-border infrastructure investment.Editor/Gong Ziwei