Renewables’ Oversupply: Grid's Main Problem, Says CENACE

Director of Mexican grid operator CENACE, Ricardo Mota Palomino, says that Mexico’s biggest energy problem is the excess of unplanned intermittent renewable energy. For this reason, he proposed to move away from the current economically-minded dispatch to an old electricity planning model used prior to the 2014 Energy Reform.

In an interview with Bloomberg, CENACE’s executive highlighted that the development of wind of solar without major planning and coordination can cause grave problems for the grid. “The most serious problem we have is that we are over-equipped in terms of intermittent generation capacity,” Mota said. In only three years, Mexico’s renewable energy capacity grew by 300 percent to 9GW. The intermittency of wind and solar energy is the biggest issue, since these power plants only function 30 percent of the day. As such, they could not support an electricity market without outside help.

Mota blames the 108MW San Carlos wind farm for causing a massive blackout in December 2020, which left 10 million without electricity. According to Mota, the plants originally Spanish owner, Acciona, had certified protection equipment that was not actually integrating in the facility. “How can a company say that there was non-existent equipment present?” said Mota, implying the company knowingly did not comply with regulation.

Earlier this year, an expert from CFE’s Transmission arm told the press that Acciona had installed provisional protection equipment which did not comply with specifications stemming from technical studies. “This caused the opening of the 400-thousand-volt link between the Laja and Güémez substations, since the faults that started the disturbance could not be properly released," he said. Independent experts confirmed that a dumpster fire further added to the problems, as did an unusually high level of intermittent energy in the dispatch at the time.

Acciona has not commented on the situation so far. Nevertheless, CFE and CENACE’s comments cannot be seen outside of the context of the López Obrador administration’s rhetoric, which favors state-owned utility CFE and paints a picture of private renewable energy developers having arrived to Mexico on the back of the 2014 Energy Reform with the sole goal of ransacking the country’s resources. In September 2021, the president sent a constitutional reform initiative to Congress, aiming to undo the previous administration’s liberation of the energy sector to yield control back to CFE and the Ministry of Energy by getting rid of independent regulators and integrating CENACE in the state utility. Previous efforts based on decrees and secondary law proposals were not successful, so the government now works to gather support for its integral constitutional reform.

Transmission and distribution experts agree that intermittency is an issue for Mexico’s grid, but that the clean energy transition is necessary, regardless, to hold off catastrophic climate change in the future. “The penetration of renewable energy might contribute to instability but it is certainly not the only hindering factor,” said Ivette Castillo, Commercial Director North America, GE Grid Solutions, at Mexico Energy Forum. Castillo sees the age and inflexibility of the grid system and a change of fuels to power the energy mix as the main reasons for instability.