1. The Context of Renewable Generation Development in Romania

In Romania distribution networks are organized into eight geographical zones. Until 2021 there were eight major DSOs, each owning the distribution network in one of these zones and holding the distribution service concession for their respective zones. Currently, there are four DSOs: two smaller operators managing one distribution zone each and two larger operators managing three distribution zones each, following mergers of previous companies.

Between 2010 and 2015, Romania experienced significant development of wind power generation, primarily located in the southeastern part of the country, close to the Black Sea and the Danube. In a short period of time, wind generators with a total capacity of almost 3 000 MW were installed in Romania. In addition to these renewable energy sources, photovoltaic installations reached an installed capacity of almost 1 500 MW in 2023, excluding prosumer photovoltaic installations, and rapidly increased to 2 300 MW in 2025. Most of these new production capacities are connected to electricity distribution networks; one of the reasons was the lower connection costs.

The energy transition is a commitment for Romania: the 2030 objective of the National Integrated Energy and Climate Change Plan 2021-2030 is 7 300 MW of wind generation capacity, including offshore, and 8 200 MW for solar installations. These ambitious targets require substantial changes in grid infrastructures, including extensive of digitalization. In this context, solutions are needed to fairly allocate the network costs to be recovered through regulated tariffs.

2. The Locational Challenge of Generation: Excessive Distance Between Generation Units and Consumption Centres Leading to Cross-Zones Energy Transits and Consequent Energy Losses

The Romanian Energy Regulatory Authority (ANRE) noticed significant electricity losses in high voltage distribution networks (110 kV) in two distribution zones, where there are many large generation units resulting in high injection surplus. One distribution zone faced with a substantial number of new renewable generation units, predominant wind, due to favorable natural conditions. The other distribution zone has a lot of important hydroelectric power plants.

In Romania, distribution costs were traditionally recovered only through withdrawal charges, so all costs of losses had to be recovered solely from consumers in each area, via these charges. But this rule needed to be changed for the costs of losses due to electricity produced in one zone and transited to other zones.

In addition to that, ANRE faced the problem of raising the network tariffs due to the increased price of electricity since 2021, which significantly impacted the cost of network losses.

All these facts determined ANRE to conduct a study, elaborated by an external consultant, to develop a methodology for quantifying losses due to electricity transit in HV distribution networks (110 kV) resulting from the injection surplus in specific zones.

The study defines the concepts of useful transit (Tu) and additional transit (Ts) of electricity for HV distribution network (110 kV) within a distribution zone and, related to them, useful and additional losses associated with these transits (CPTu, CPTs). The useful transit (Tu) corresponds to the flow from HV distribution network related to the consumption in the zone at all voltage levels. The additional transit (Ts) is obtained by difference of the energy entering the 110kV grid and the useful transit. The study uses data for intervals of 15 minutes over one year. The methodology establishes a regression function using intervals where additional transit is under 20% of useful transit. After that, it applies this function to intervals with bigger transit and determines for these intervals the useful losses (CPTu). Additional losses (CPTs) will be calculated as the difference, for each interval with bigger transit, between total losses and useful losses.

3. The Proposal for an Injection Charge for Generators

The study revealed that in the two distribution zones where losses in high-voltage distribution networks are substantially larger than in other zones, there are additional transit and additional losses due to generation. The methodology described above allowed operators to quantify the level of these additional losses.

Given the findings of the study, ANRE introduced the requirement for all DSOs to apply the methodology every year, to verify if there is additional transit and to calculate additional transit and additional losses if there is the case. The cost of additional losses due to generation calculated for one distribution zone is recovered from producers connected to the distribution network in that zone, with capacity of 5 MW or more.

4. The Consultation and Explication Process to Generation Stakeholders

During the duration of the study that was 6 months, ANRE published the study two times, first with partial results and then complete. 

During these public consultations there were a few meetings with the consultant and the stakeholders: DSOs, producers and professional organisations of producers. These discussions were very useful because at first producers were reluctant, but they were convinced in the final due to explications and the data that showed without doubt the additional transit.

There were some technical suggestions from stakeholders that improved the method, but nothing notable.

5. Entry Into Force and Expected Results of the New Regulatory Measure

For 2025, ANRE approved the injection charge for producers with a capacity bigger than 5MW, connected to distribution networks in two of the eight geographical zones. The injection charge covers only losses in HV distribution network due to electricity generation surplus relative to the local consumption; the charge amounts in one zone to 6% and in the other to 17% of the withdrawal charge approved for the same voltage level. 

The immediate result of the measure is the correct allocation of the cost. ANRE also expects this to be a serious signal for new producers to locate in other geographical zones with withdrawal surplus.