Não cabe mais energia solar na rede. O plano do ONS para evitar blecautes

The growing popularity of solar panels over recent years has led to an increasing surplus of energy generation during the day, raising the risk of a power grid collapse during periods of low consumption. To prevent such a scenario, the National Operator of the Electric System (ONS) is preparing a new mechanism that could automatically cut the production of small-scale photovoltaic power during critical moments.

This plan, set to be implemented by the end of the year, comes after dips in demand on holidays like Father's Day and other days of rest have placed the system at a high risk of blackouts. The ONS has already practiced forced shutdowns of large-scale solar and wind parks to balance the system, known as curtailment. Recently, it also activated an emergency plan for cuts from smaller plants such as small hydroelectric power stations and biomass plants connected to the distribution network, which was activated in June during the Corpus Christi holiday.

"Now we are finalizing another scheme, which would be another layer of protection," said Alexandre Zucarato, the Director of Planning at the ONS. The proposed Regional Generation Relief Scheme (ERAG) is expected to reach around 3 gigawatts of capacity for remote solar generation linked to the network that can be cut "in a stepped manner" as needed to rebalance the system.

The logic is similar to an emergency scheme triggered by the ONS that automatically turns off the lights in selected areas when there is not enough energy in the network, called the Regional Relief Scheme for Load (ERAC). Both maneuvers in the operation of the electric grid are necessary to ensure that generation and consumption are always at the same level in the system; when this fails, the frequency drops and blackouts can occur.

The measure under preparation at the ONS does not require any approval from the Government or Aneel. "If necessary, to save the system from a complete blackout, we can control the load, which is the final customer of the electric sector. So there is nothing extraordinary about cutting generation automatically and point-wise to prevent a blackout," Zucarato said after participating in a sector event at MegaWhat.

"The system's ability to handle load peaks is reaching its limit. We are using all measures we can, with a sequence of defensive lines." Portugal has surpassed the 51 gigawatt mark in installed solar panel capacity on rooftops and small-scale wind parks. Moreover, the ONS estimates there could be another 14 gigawatts of unregistered solar generation in the distribution systems, making it "invisible."

All these solar installations reach their peak production at the same time, typically in the early afternoon, overloading the network, and the ONS has no capacity to control this generation. The new generation management mechanism by the ONS will be presented to distributors at a workshop planned for the following month to assess the feasibility of the measures, with the goal of implementing at least one pilot version by the end of the year.

If adopted, the distributors themselves would be responsible for implementing the cuts of the "ERAG." The large connected wind parks and rooftop installations are likely to be the ones entering the plan, as they are more widespread in the regions with concentrated installations. The plan is another measure to deal with the surge in decentralized solar generation, which has been challenging the electric sector.

However, the challenge is that these wind parks and rooftop installations continue to grow. One expert summarized it: "The ONS is looking at the problem and redistributing its impacts, but someone will eventually need to find a solution."