In the conferences he offers every morning from the National Palace, in his travels across the country, in his meeting with the United States envoy for climate change. The president of Mexico, Andrés Manuel López Obrador, has not tired of repeating in recent months that the great bet of his Government to comply with its environmental commitments is hydroelectric energy, “the cheapest and cleanest.” Since then, experts have come forward to contradict that claim: It is three times more expensive than solar and wind, and is increasingly considered less clean due to its methane emissions, its impact on ecosystems and its dependence on a scarce resource: water.

But, above all, what they question is the idea that hydroelectric plants can increase their generation enough to reach the goal of 35% clean energy by 2024 that Mexico has proposed. Last year, these plants produced less than 9% of the total. Rosanety Barrios, an independent industry analyst, explains that the vast majority of Mexico’s hydroelectric plants are controlled by the state-run Federal Electricity Commission (CFE) and were built between the 1960s and 1980s, making them quite outdated.

“The president’s approach is to modernize what can be done, which is essentially the turbines. But the improvement that you can obtain does not go beyond 10% in efficiency ”, says the expert. So far, the CFE plan does not contemplate building new dams, due to the strong social opposition that has been encountered in recent decades. Paso de la Reina, Las Cruces, Chicoasén II … the list of new hydroelectric plants that have been held back by the rejection of the population is long.

Therefore, what the state company has announced is an investment plan of 20,000 million pesos (1,000 million dollars) to rehabilitate nine plants and build another three on existing dams, mainly in Sonora and Sinaloa. But the CFE itself has recognized that these plans will contribute, at most, an increase of 1,860 gigawatts per hour per year, which represents 0.6% of the total electricity generation in Mexico. Far from what the country needs to reach its goal of 35% clean energy, which currently stands at 25%.

Truly green?

The limits that these types of plants face are not solely technological. Climate change is making droughts more frequent and prolonged in the country and, when water is scarce, human and agricultural consumption are priorities. “If we have a year with little rain, the water stored there has to be taken care of for human beings. If there is an attempt to violate these rules, you have to be very concerned about what may happen to human consumption, ”Barrios warns.

On the other hand, just as droughts are longer, torrential rains are more common as a result of global warming, which can lead to the overflow of dams, as happened in Tula last September. That month, hydroelectric generation reached a peak of 16% of the country’s total. “But to think that you can maintain that same level throughout the year or even double it, as the president has said, is one hundred percent impossible.” In fact, in January, one of the months when it rains the least, hydroelectric plants generate around 4%.

Like a whiting that bites its tail, hydroelectric plants are not only affected by climate change, but also contribute to worsening that crisis, says Astrid Puentes, former director of the Inter-American Association for the Defense of the Environment (AIDA). At the time of its construction, large areas of territory are deforested to create reservoirs -which releases CO2 into the atmosphere- and ecosystems and the way of life of the population are affected by diverting the riverbed.

In addition, the organic matter that is flooded in the dams enters a state of decomposition and emits methane, one of the most powerful greenhouse gases. “Before deciding to rehabilitate existing hydroelectric plants, Mexico should make a good evaluation of what alternatives there are today, not in the 70s. Today, in the 21st century, hydroelectric power loses to solar and wind power in terms of social, climatic and environmental impacts ”, says the lawyer.

The background: the electrical reform

Víctor Ramírez, doctor of science from UNAM and spokesperson for the Mexico, Climate and Energy Platform, believes that the government’s push for hydroelectric plants is nothing more than political rhetoric. Because the underlying issue is, from his point of view, the electricity reform that the president is pushing against all odds. The proposal seeks to modify the Constitution to return the lost power to the CFE, giving it control of 54% of the generation, well above the current 38%, and leaving the remaining 46% to private parties.

“If you want to reach that 54%, they will not be able to do it only with hydroelectric plants. They are going to have to do it with their thermoelectric and coal plants, ”says Ramírez. Under the proposal, the hydroelectric plants would be the first in line to dispatch their energy, limited by the availability of water, and the next in line would be the CFE’s conventional plants, which operate with fossil fuels such as fuel oil, gas and coal. Therefore, says the expert, it seems difficult that this reform does not imply a considerable increase in the country’s greenhouse gas emissions.

Another myth that he wants to dismantle is that hydroelectric power is the cheapest. According to data from the Energy Regulatory Commission, it costs 1,211 pesos per megawatt / hour, almost three times more than the 377 pesos for solar and wind power, in the hands of private companies. Why is it so much more expensive? “Because, among other things, water is a limited good that has a price, unlike the sun or the wind.” For this reason, currently the first energies that are dispatched are solar and wind: because they are the cheapest.

But for Mario Morales, CFE planning coordinator, the current situation “is not competition but dispossession,” because it relegates the state-owned plants, which are more expensive and polluting, to the background. In an interview with EL PAÍS, the official defends the hydroelectric rehabilitation plan, although he acknowledges its limited nature, and emphasizes that “the most important thing is that it will increase the useful life of the plants for another 50 years.”

Asked about the possibility of reactivating the construction of the controversial Chiacoasén II hydroelectric project in Chiapas, Morales confirms that it is in his plans and assures that the details will be announced in the coming weeks. The idea worries Sandra Moguel, an environmental lawyer who has accompanied the struggle of residents against several hydroelectric plants in Mexico, such as the one proposed in 2014 for Nayarit, known as Las Cruces.

The dam would have been installed on the San Pedro Mezquital river, considered sacred by the Cora indigenous people of the region. The impacts had endless ramifications: thousands of families displaced to flood the land, fishing communities affected by the river dam, one of the main wetlands in Mexico without essential food for its mangroves. The movement to fight against Las Cruces and a flood of appeals stopped the project, but the lawyer recalls that the CFE continues to have construction and operation permits.

“The communities are quite fearful of this plan to reactivate hydroelectric plants as a fundamental activity of power generation. They have approached us to ask, what is going to happen to us? ”, He says. He has only been able to answer them that, if the reform promoted by the president is approved, the possibility that these projects will be reactivated cannot be ruled out.

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