Spain’s energy regulator, the National Commission for Markets and Competition (CNMC), has launched a short public hearing on an urgent resolution to temporarily adjust four grid operating procedures. The move aims to stabilise voltage on the peninsular power system, following a request from the system operator on 7 October. The operator reported rapid voltage swings over the previous two weeks, which, although within limits, posed risks of demand or generation trips and threatened security of supply. This urgency has led to a condensed five-day consultation period.
The proposed changes come in the wake of an ENTSO-E expert panel investigation that identified overvoltage as a contributing factor in the April blackout of the Spanish grid. During that incident, voltages in southern Spain surged sharply and spread into Portugal, triggering a cascade of generator trips and a rapid frequency decline.
The CNMC’s proposed modifications include a flexible publication time for the provisional viable day-ahead schedule, allowing upward-reserve management within the day-ahead technical constraints process, and other adjustments. The regulator attributes the voltage volatility to several factors: rapid programme changes, the growth of power-electronics-based generation concentrated in specific grid areas, limited continuous voltage regulation by some technologies, slow responses from units with continuous control, and rising self-consumption. The latter reduces observed transmission demand during high solar periods, heightening voltage sensitivity.
CNMC frames the package as “exceptional and temporary,” noting that it will conduct deeper analysis while the new dynamic voltage-control service under PO7.4 is rolled out. The changes are designed to mitigate potential impacts on balancing, constraints, and market competitiveness.
This development underscores the challenges of integrating renewable energy sources into existing grids and the need for adaptive regulatory frameworks. As Spain grapples with these issues, the sector may see broader implications for grid stability, market design, and the pace of renewable energy adoption. The temporary nature of the measures suggests a recognition of the need for more permanent solutions, potentially spurring innovation in voltage control technologies and grid management strategies.