That the El Nino phenomenon will arrive in Colombia is practically confirmed. The probability that it will materialize from the May-July period rose to 61%, compared to just 25% projected in March. The chances are increasingly higher. But to that panorama, problematic in itself, another serious threat has been added: that of an energy blackout due to reservoir levels.
In addition, for authorities, the 2026 El Nino in Colombia would not be common. It could be a “super Nino”, the most intense in at least a decade, with anomalies in the temperature of the tropical Pacific Ocean that could exceed 2 °C above the historical average.
The equation is simple: the absence of rainfall would have a direct impact on reservoirs and hydroelectric plants, from which approximately 70% of the country’s electricity is generated. It is already practically a common fact that, with the El Nino phenomenon, reservoirs fall below 30% of their capacity.
Reservoirs in Colombia are at 60% filling
Last year, the El Nino phenomenon brought reservoirs to a historic minimum of 27% filling. And in April of that year, the country was one week away from a blackout, according to Natalia Gutierrez, president of Acolgen and of the National Business Council, quoted by El Colombiano.
That same outlet recalls that thermoelectric generation, at that critical moment, was the one that had to cover 55% of the total consumed in one day in Colombia, then 37% with gas and 18% with coal, while the price of energy on the market shot up more than 200%, transferring pressure to the entire economy.
Currently, the reservoirs of the National Interconnected System (SIN) are averaging 60% filling. Still far from the desirable level, according to XM, administrator of the wholesale energy market, which is 80% for when the period of lower rainfall begins, which is estimated to be in August.
That implies an increase of 17.19 percentage points in just 16 weeks, to return to the level recorded in January, when the first cold front arrived.
For the summer, reservoirs must be above 80%
“Prior to the 2026-2027 summer season and in scenarios of deficient hydrology such as those analyzed, the aggregated reservoir level of the SIN at the beginning of summer should be above 80%, with maximum values that should be reached from August, in order to guarantee the supply of demand and comply with reliability indices,” XM explained in a bulletin.
Along the same lines, Sergio Cabrales, professor and consultant in the mining-energy sector, agreed that 2026 began with reservoirs at 80%, but currently they stand at 60%. “It is required to begin the next summer with reservoirs above 80% to cope with the energy summer of 2026-2027,” he said, quoted by the Antioquian newspaper.
For her part, Sandra Fonseca, former director of Asoenergia, stated in the economic newspaper La Republica that the management of hydroelectric plants should increase the pace of water storage and carry out a detailed and constant review of water inflows. Even so, she warned that the system will continue under pressure in terms of prices, availability and reliability.
The main alternative to meet energy requirements in the dry period is thermal generation, either with natural gas or coal, which, in the words of former Minister of Mines and Energy Amylkar Acosta, quoted by the same outlet, acts as a backup to the hydraulic source. But, due to the way in which electricity generation capacity is distributed (62% hydraulic, 29.2% thermal and 8.8% solar), the specter of a blackout is becoming increasingly larger.