The market determines who supplies the electricity being purchased. The system operator then checks whether the resulting generation and consumption schedule can be carried out safely. If a power line lacks sufficient capacity, or the operating arrangement cannot maintain acceptable voltage, that schedule needs to change.
These circumstances are known as technical constraints. To resolve them, the operator can adjust generation, demand or storage schedules. It might, for example, increase production where it is needed to operate the grid safely, even though the initial market clearing did not select that volume. Such actions are paid for through established mechanisms.
According to Red Eléctrica, the cost depends on the amount of adjustment required and the offers made by participants, mainly generators. It is not revenue earned by the operator for every megawatt-hour dispatched. A low initial purchase price for energy therefore does not mean that every subsequent system action is inexpensive.
Red Eléctrica reports that resolving technical constraints cost €3.614 billion between January and September 2026. This is not the cost of all “grid stability”, nor does it relate only to reinforced operation following the 2025 blackout. The operator attributes less than €275 million over the same period to the narrower category known as reinforced scheduling.
CNMC, Spain’s markets and competition regulator, is examining how these costs are allocated. Its report dated 8 October states that on 27 July it asked the operator to analyse the existing mechanism for financing technical constraints. The aim is to assess how accurately it reflects costs and what incentives it gives consumers, including when they choose to use electricity.
The report describes work in progress, involving discussion with participants and preparation of a proposed regulatory change. Requesting an analysis does not introduce a new tariff or establish a future surcharge or discount for a Costa Blanca home.
The way current costs affect a bill depends on supply terms. Under the regulated PVPC tariff, they are incorporated through an established methodology. In the free market, consumers should check whether they are included in the advertised price, passed through separately and subject to review.
Consider a hypothetical business in Alicante comparing a fixed tariff with an offer showing the wholesale price and a small supplier fee. A meaningful comparison requires knowing where adjustment costs are included in each option. A low supplier fee alone does not reveal the full contract cost.
Similarly, technical-constraint costs cannot simply be subtracted from UNEF’s estimate of solar savings: the periods, cost categories and calculation scenarios differ.
For consumers, CNMC’s discussion matters primarily because future rules could change how payments are shared. Redistribution itself does not remove the physical need to regulate the grid. Reducing the necessary costs and deciding who pays them require separate decisions.