Serbia’s 2029 Renewable Connection Delay Highlights Need for Major Grid Expansion

Serbia’s decision to postpone connection-study procedures for new variable renewable-energy projects until late 2029 has exposed the growing gap between renewable generation ambitions and the country’s electricity network capacity.

The measure does not represent a complete ban on new electricity connections. It mainly affects large wind and solar projects classified as variable renewable-energy facilities. Projects already covered by connection agreements, qualifying active customers, storage facilities and developments able to secure required balancing reserves may continue through alternative procedures.

Elektromreža Srbije (EMS) has continued processing categories allowed under the updated framework, including applications for standalone battery-storage facilities. For a significant portion of Serbia’s planned wind and solar pipeline, the decision effectively creates a temporary freeze. Applications already submitted under the affected procedure are expected to enter the connection-study phase between 1 September and 31 December 2029, while study agreements are generally not expected before August 2029. Previous plans had anticipated processing during 2026.

Renewable projects face longer development timelines

A connection study is only the initial technical stage of grid access. It defines the connection location, required network upgrades, voltage level, operating conditions, protection requirements and allocation of connection costs. Following completion of the study, developers must still secure connection agreements, complete spatial planning, obtain land rights, prepare designs, receive environmental and construction permits, arrange financing, procure equipment, build facilities, complete testing and begin commercial operation.

A renewable project receiving its connection study at the end of 2029 may therefore remain several years away from operation. Projects requiring new 400 kV or 110 kV transmission lines, additional transformer capacity or new substations could realistically reach energisation between 2033 and 2036, even if generation facilities themselves can be constructed within 18 to 30 months.

The challenge reflects different construction cycles. Utility-scale solar plants can be developed relatively quickly once permits, land and equipment are secured. Wind projects require longer civil works and turbine delivery schedules but remain significantly faster to complete than major transmission infrastructure. A new overhead line crossing multiple municipalities, hundreds of land parcels and environmentally sensitive areas requires a much longer preparation and construction process.

EMS transmission projects form backbone of grid upgrade

Serbia’s response requires more than delaying applications. The country must use the period before 2029 to complete physical network investments needed when the connection process resumes. A connection-study window without completed or contractually secured grid reinforcements would simply move the bottleneck from administrative procedures to construction schedules.

One of the key projects is BeoGrid 2025, valued at approximately €205 million, which is designed to strengthen electricity supply around Belgrade, improve connections with northern Serbia and enable evacuation of renewable generation from the South Banat region. The project includes the new 400/110 kV Beograd 50 substation, planned with two 300 MVA transformers, as well as a new double-circuit 400 kV connection towards the Čibuk 1 switching station.

Additional elements include integration of the existing 400 kV Mladost–Novi Sad 3 line into Beograd 50, new 110 kV connections, and a double-circuit cable connection towards the airport-area Beograd 49 substation. Two single-circuit 400 kV line sections with a combined length of approximately 25.5 kilometres entered construction in 2025. Investment in the Beograd 50 substation is expected at around €50 million. The project is intended to reduce loading at TS Beograd 5, improve supply reliability for New Belgrade, Zemun and the airport corridor, and create transmission capacity for renewable generation from South Banat. Earlier EMS system assessments indicated that the broader North Continental South-East corridor could support evacuation of up to 3 GW of generation from South Banat while increasing cross-border capacity with Romania.

High-voltage corridors expand national transmission capacity

Another strategic investment is the Trans-Balkan Electricity Corridor, which is upgrading Serbia’s western and central transmission backbone from 220 kV to 400 kV. The corridor strengthens electricity flows from Romania through Serbia towards Bosnia and Herzegovina and Montenegro while connecting with the subsea Montenegro–Italy interconnector. The third section includes a new approximately 109-kilometre 400 kV overhead line between Obrenovac and Bajina Bašta, expansion of the Bajina Bašta substation from 220/35 kV to 400/220/35 kV, and new 400 kV bays at Obrenovac.

In 2026, EMS signed a contract worth around €36 million for substation-related elements of this section. The planned Central Balkan Corridor represents another major investment programme. Designed for development through the next decade, it aims to improve east-west and north-south electricity transfers across Serbia. The concept includes approximately 310 kilometres of new high-voltage lines, two new 400 kV substations and estimated investment of around €195 million.

The first section includes a new 400 kV node near Požarevac and a double-circuit connection towards TS Jagodina 4, with completion targeted around 2030. Later phases would strengthen links from Niš through Kruševac and Kraljevo, extend towards Požega and the Bosnian border, and connect further with the Trans-Balkan system. Full completion is expected closer to 2034.

Northern Serbia requires additional grid reinforcement

The planned Pannonian Corridor is focused on northern Serbia and includes reinforcements involving Subotica, Sombor, Novi Sad, Sremska Mitrovica and Hungary. The project is intended to improve transport capacity for wind and solar generation from Vojvodina while increasing cross-border exchange capability. EMS modelling has linked future renewable developments, including the approximately 300 MW Torak wind project, with completion of this corridor. Together, these investments demonstrate that Serbia’s challenge is not limited to one missing transmission line. The country requires coordinated development across South Banat, Bačka, Srem, the Belgrade area, the Drina corridor, western Serbia, the Kostolac–Požarevac region and central and southern Serbia.

Grid stability requires digital systems and reactive power investment

The transmission challenge extends beyond physical congestion. EMS’s 2025–2034 transmission development plan identifies voltage-management issues, particularly during periods of low demand when lightly loaded 400 kV lines generate reactive power and increase voltage levels. Planned solutions include variable shunt reactors at locations such as Beograd 20, Kraljevo 3 and Novi Sad 3, with commissioning indicated around 2029.

The expansion programme must therefore include not only additional lines but also power transformers, voltage-control equipment, reactive compensation systems, digital substations, monitoring systems, protection upgrades, telecommunications infrastructure and cyber-secure SCADA platforms. A new 400 kV line cannot eliminate constraints if substations lack sufficient transformer capacity, protection systems or downstream evacuation routes.

EMS and EDS face parallel investment requirements

The distinction between transmission and distribution infrastructure remains critical. EMS operates Serbia’s transmission network, mainly at 400 kV, 220 kV and 110 kV levels, while Elektrodistribucija Srbije (EDS) manages medium- and low-voltage distribution networks serving households, businesses, industry, distributed generation and smaller renewable facilities.

Serbia therefore requires two parallel programmes: an EMS-led expansion of high-voltage corridors and a nationwide modernisation of distribution networks, including 35 kV, 20 kV and 10 kV systems, transformer substations, automation, metering and voltage management. The distribution system was originally designed around one-directional electricity flows from large power plants to passive consumers. It now must integrate rooftop solar, industrial generation, batteries, electric vehicles, heat pumps and electricity-intensive factories.

Distributed solar can overload local transformers and feeders even when national transmission capacity remains available. At the same time, local renewable generation may exceed the capacity of the 110 kV connection feeding a distribution area.

EDS modernisation programme targets digital distribution

Serbia has started upgrading distribution infrastructure through a €140 million medium-voltage modernisation programme involving EDS and Schneider Electric. The programme combines medium-voltage equipment with advanced distribution-management systems and distributed-energy-resource technologies. It aims to reduce outages, lower losses and improve operational control of a more decentralised electricity network.

The Agency for Energy of the Republic of Serbia (AERS) approved the EDS development plan for 2025–2034 and the investment plan for 2025–2027 in April 2026. Digital systems cannot replace physical infrastructure. Network software can identify constraints and optimise operations, but it cannot eliminate limits caused by insufficient conductors, transformers or switchgear.

Industrial expansion increases electricity infrastructure demands

Grid development is becoming increasingly important for Serbia’s industrial strategy, which includes ambitions in electric-vehicle manufacturing, batteries, data centres, mining, metals processing and other electricity-intensive sectors. Large industrial investors require reliable connections, predictable expansion capacity and access to low-carbon electricity. New renewable generation, storage and industrial demand must therefore be planned together. Flexible industrial loads, batteries, thermal storage and electrolysers can help absorb local renewable production and reduce export peaks when coordinated properly.

Standalone batteries, however, cannot automatically solve congestion problems. A battery located on the wrong side of a network constraint could increase pressure on an already limited grid connection. EMS and EDS will need connection requirements covering charging restrictions, dispatch signals, reactive-power capability, fault-ride-through performance and availability for balancing services.

Renewable growth requires flexibility beyond transmission lines

EMS modelling estimates peak electricity demand at approximately 6.79 GW in 2029. Under high-renewable scenarios, Serbia’s net load could shift from around positive 6 GW to negative 4 GW, meaning wind and solar production could exceed domestic consumption by several gigawatts at certain times.

Managing these conditions will require more than transmission expansion. Serbia will need flexible hydropower production, faster balancing mechanisms, battery storage, demand response, regional electricity-market integration and the planned Bistrica pumped-storage project. Cross-border capacity provides additional flexibility, but neighbouring countries may experience similar renewable surpluses at the same time.

Grid investment requirement reaches billions of euros

The connection delay is also linked to system balancing and operational security. Serbian regulations allow some variable renewable projects to avoid postponement if they secure additional secondary reserve capacity or allocate qualifying reserve from existing assets. This does not remove location-specific network limitations. Officially identified Serbian transmission projects are moving towards a programme of approximately €1 billion, with around €500 million of priority investments targeted by the end of the decade.

A broader 2026–2035 transmission investment programme could require between €1.5 billion and €2.5 billion, depending on new transmission routes, substations, transformers, cross-border components and reactive compensation requirements. A parallel distribution modernisation programme could require another €1.5 billion to €2.5 billion over the same period. The combined Serbian grid investment requirement could therefore reach approximately €3 billion to €5 billion over a decade, covering high-voltage corridors, substations, transformer replacement, distribution reconstruction, automation, smart metering and system reserves. A greenfield double-circuit 400 kV overhead line typically costs around €0.8 million to €1.5 million per kilometre, while major 400/110 kV substations can require €40 million to €80 million depending on configuration and transformer capacity.

Large 110 kV substation reconstructions may range from €10 million to €30 million, while major power transformers can cost several million euros before additional equipment and civil works. Long procurement periods create additional risks. Large power transformers can require 18 to 36 months from specification and contract signing to delivery, while high-voltage breakers, reactors, protection equipment and specialised conductors face manufacturing constraints.

Renewable developers face financial impact from delays

A prolonged grid-access delay directly affects renewable project economics. Developers must continue maintaining land rights, environmental studies, guarantees and project teams while facing uncertainty over equipment costs, construction prices and power-purchase agreements. For a representative wind project, a 12-to-18-month grid delay can reduce equity internal rates of return by approximately 1.5 to 3 percentage points, depending on financing structure and development costs. Solar projects may experience a reduction of approximately 1 to 2.5 percentage points, with larger impacts if delays result in loss of auction awards, power-purchase deadlines or equipment reservations.