Electricity prices in Europe are determined by a complex interaction of fuel costs, renewable generation, transmission constraints, and cross-border market integration. In the Central Europe–South-East Europe corridor, price formation reflects both local generation structures and the broader dynamics of the continental electricity system. The interconnected nature of European power markets means that developments in one region can rapidly influence prices in another. As a result, electricity price formation must be understood not only within national markets but across the wider network of exchanges linking Germany, Austria, Hungary, Slovenia, Croatia, Romania, Bulgaria, Serbia, and Greece.
Wholesale electricity markets in Europe operate according to a marginal pricing mechanism. Power plants submit bids reflecting the cost at which they are willing to generate electricity for each hour of the day. These bids are arranged in ascending order of cost to form the so-called merit order. Low-cost renewable generation such as wind and solar typically enters the market first because its operating costs are minimal. Hydropower and nuclear plants follow due to their relatively low marginal costs and operational constraints. Thermal generation using coal or natural gas generally appears later in the merit order because fuel expenses and carbon costs increase the price required to operate these plants profitably.
The electricity price in each hour is determined by the most expensive power plant required to meet demand at that moment. This plant is known as the marginal unit. Once the marginal generator is identified, all electricity produced during that hour is paid at the price set by that unit, regardless of the cost of the individual generators. This pricing system ensures that electricity markets allocate generation efficiently while providing incentives for investment in new capacity when supply becomes scarce.
The structure of generation across South-East Europe strongly influences how electricity prices emerge within this merit-order framework. Regional electricity supply in 2026 reflects a diversified mix of generation technologies. Hydropower contributes approximately 31 percent of total electricity production across the regional system, making it the single largest generation source. Coal-fired plants account for roughly 19 percent, natural gas generation contributes about 19 percent, nuclear power supplies approximately 14 percent, solar generation produces close to 12 percent, and wind generation represents around 3 percent of the regional electricity mix. Each of these technologies plays a distinct role in shaping price formation under different system conditions.
Hydropower often acts as a flexible balancing resource capable of responding rapidly to price signals. Reservoir-based hydro plants can adjust output quickly by releasing more or less water through their turbines. This ability allows hydro operators to increase production during periods of high electricity demand or elevated prices while conserving water when prices are lower. Because hydroelectric plants can respond so quickly, they frequently help maintain system stability when renewable output fluctuates unexpectedly.
Coal-fired power plants remain an important component of electricity generation in several South-East European countries, particularly Serbia, Bulgaria, and parts of Romania. These plants typically operate as baseload generation because they are designed to run continuously for extended periods. However, rising carbon costs under the European Emissions Trading System have increased the operating costs of coal-fired plants, gradually reducing their competitiveness relative to other generation technologies. Even so, coal plants continue to influence electricity price formation during periods when renewable generation declines or electricity demand rises significantly.
Natural gas generation plays a critical role in determining electricity prices because gas plants often function as the marginal generation technology. Gas-fired power stations are highly flexible and can adjust output quickly to balance fluctuations in renewable generation or demand. However, their operating costs are heavily influenced by natural gas prices. When gas prices rise, the cost of producing electricity from gas plants increases correspondingly, raising the marginal price within electricity markets. The relationship between gas markets and electricity prices therefore remains a central feature of European power price formation.
Solar and wind generation introduce a different dynamic into electricity markets because their output depends on weather conditions rather than fuel costs. When solar or wind generation is abundant, large volumes of low-cost electricity enter the system simultaneously. This additional supply pushes more expensive generators out of the merit order and lowers wholesale electricity prices. In extreme cases, when renewable generation exceeds demand, electricity prices may fall close to zero or even become negative as producers pay to avoid shutting down their facilities.
However, renewable generation also introduces volatility into electricity price formation. Solar output declines rapidly after sunset, while wind generation can fluctuate unpredictably depending on atmospheric conditions. When renewable output falls unexpectedly, other generation technologies must increase production to maintain the balance between supply and demand. Gas-fired plants frequently fill this role because they can respond quickly to changing system conditions. As a result, electricity prices often rise sharply during evening hours when solar generation disappears and demand remains high.
Cross-border electricity trading further influences price formation across Central and South-East Europe. Interconnectors linking national electricity systems allow power to flow from markets where electricity is relatively inexpensive toward those where prices are higher. This process gradually equalizes prices across interconnected regions while ensuring that available generation resources are used efficiently. However, transmission capacity between markets is limited, meaning that price convergence is often incomplete. When interconnectors become congested, electricity flows cannot increase further, causing price differences between neighbouring markets to widen.
Hungary occupies a particularly important role within the regional price formation process because it connects multiple trading corridors simultaneously. Electricity can flow into Hungary from Austria and Slovakia in the north, from Romania in the east, and from Serbia and Croatia in the south. Because of this central position, price movements in Hungary often reflect the balance of supply and demand across several neighbouring markets simultaneously. When prices rise in Western Europe due to high demand or reduced renewable generation, these signals frequently propagate eastward through Austria into Hungary before influencing markets further south.
The relationship between electricity prices in Central Europe and those in South-East Europe can therefore be understood as a cascading system of price signals moving through interconnected markets. Germany and Austria often act as primary price anchors because of their large market size and high liquidity. Hungary serves as an intermediary hub that transmits these price signals into the Balkan region, where electricity markets such as those in Slovenia, Croatia, Romania, and Serbia respond according to their local generation structures and demand patterns.
Seasonal factors also play an important role in shaping electricity price formation. Electricity demand tends to increase during winter months when heating requirements rise, while summer heatwaves can also push demand higher due to increased air-conditioning usage. At the same time, hydrological conditions influence hydroelectric generation, while weather patterns determine solar and wind output. These seasonal variations can significantly alter the balance between supply and demand, producing corresponding changes in electricity prices.
The electricity price data observed in 2026 illustrates how these various factors combine to shape price formation across the Central Europe–South-East Europe corridor. Day-ahead electricity prices in the Hungarian market reached approximately €142.6 per megawatt-hour, while neighbouring markets traded at slightly lower levels, including around €137.9 per megawatt-hour in Slovenia, €134.6 per megawatt-hour in Croatia, and approximately €126.6 per megawatt-hour in Romania and Bulgaria. These values reflect the close integration of regional electricity markets as well as the influence of cross-border electricity flows in maintaining price convergence.
At the same time, lower prices in markets such as Serbia, where day-ahead prices approached €99.6 per megawatt-hour, demonstrate how local generation conditions and market liquidity can still produce deviations from regional price averages. When domestic generation is sufficient to meet demand, or when cross-border interconnection capacity is constrained, national electricity prices may diverge temporarily from neighbouring markets.
In the evolving European electricity system, price formation is therefore the result of multiple interacting forces. Fuel costs, renewable generation, hydrological conditions, and transmission infrastructure all contribute to determining which power plants become the marginal generators that set market prices. As renewable energy continues to expand and electricity markets become more integrated across national borders, the complexity of these interactions will increase further.
The electricity trading data observed in 2026 demonstrates that the Central Europe–South-East Europe corridor has already developed into a highly interconnected regional market in which price signals travel rapidly across borders. Understanding how electricity prices form within this system requires not only an analysis of individual national markets but also a broader perspective on the network of exchanges, transmission corridors, and generation technologies that collectively define the European power market.
