Brais Lorenzo / EPA
REN has left notices about the risks of blackout in its last investment plan. Solutions were investing in equipment to give stability to the power grid; and prevent deviations between production and consumption can lead to a blackout.
On April 28, a widespread cut in electric supply left.
Closed airports, traffic congestion and traffic in large cities and lack of fuels were some of the consequences of blackout.
In December 2024, in its last investment plan, the REN – National energy networks already had warned of the possibility of such an event.
In the document, the company referred three times the expression blackout (blackout).
It was not a lack of warning
According to, in the proposal of Development and Investment Plan of the National Electricity Transport Network (PDIRT), REN proposed invest in equipment to give stability to the power grid.
It would be almost 1.7 billion euros Throughout the 1920s to 2034 – an amount that, according to the weekly, more than doubles the decenal investment of the previous proposal of PDIRT. Ren believed that this value could be accommodated without weighing in the pockets of consumers.
The plan was in public consultation between January and February this year; and need state approval for investments. But, as the Expresso, before the government pronounces, the Essential – Regulatory entity of energy services You have to issue an opinion – which has not yet happened.
REN remembers in the PDIRT that when there are imbalances between production and consumption there are variations in the frequency of the power grid. Therefore, the company proposed, in the PDIRT, the Installation of two synchronous compensators in southern Portugal.
The idea is to “prevent more serious situations of inertia deficit in the system that, due to severe imbalances between generation and consumption, can lead to higher frequency deviations, which may lead to the performance of minimal or maximum frequency of consumption and generation, and ultimately lead to a blackout” – Quotes the Express.
However, REN clarified that a final decision on this investment in synchronous compensators depended on a monitoring network behavior and evaluation of hours when the network operates below a threshold that was still (at the end of 2024) for defining Por Uma Metodology da made.
For the past two weeks, several experts have argued that there are technical solutions to make the network more resilient in a context of greater penetration of photovoltaic and wind sources.
An example is, writes the Express, for example, to provide the solar centers of type inverters grid forming – capable of fixing their own frequency, rather than limiting themselves to follow the network.
Last week the INESC TEC Institute An analysis of blackout of April 28, noting that there is already in the market information and monitoring systems that allow us to preserve the integrity of the networks and avoid cascade fall of the electrical system.
The adoption of probabilistic methodologies, the installation of power stabilizers and the deepening of the reserve markets will also be options below. In addition, it will also be important to adjust the protective parameters of wind parks and solar centrals so that they are a little more tolerant of frequency oscillations rather than immediately turning off with small deviations – concludes the study, cited by the weekly.
