A Cenepred risk assessment has flagged 116 hydroelectric plants operating across Peru as sitting at high or very high danger from huaicos, landslides, and floods during the upcoming 2027 summer season — a scenario that, if it unfolds, threatens plants whose reservoir supply comes from the same Andean highland terrain where El Niño historically concentrates drought, according to the national mining and energy society and projections cited by Gestión.
That threat is not theoretical. Peru's 191 hydroelectric plants supply more than half of all electricity fed into the national grid, and every major El Niño event on record has sent spot-market energy prices soaring, squeezing businesses that have no rate protection.
A Double-Edged Threat to Peru's Grid
Most headlines focus on flooding. The electric sector faces something harder to visualize: a simultaneous infrastructure and hydrology crisis.
Peru's sierra is where the double danger converges. Excessive rainfall triggers huaicos and sediment flows that can force immediate plant shutdowns, while drought conditions further south reduce the river flows that keep turbines spinning. Both can happen within the same season under a strong El Niño, as the coastal north floods while the southern highlands dry out.
Peru's Cenepred published its Summer 2027 risk scenario in August 2026, estimating that nationwide 18,453 populated areas face very high risk from landslides and debris flows, and that 1,109 additional communities are at very high risk from flooding. The hydroelectric plants located within or adjacent to these critical zones represent the energy dimension of the same catastrophe.
The severity of the current outlook is without recent precedent. ENFEN's September 2026 alert placed the probability of an extraordinary-magnitude coastal event at 62%, with temperature anomalies along the northern coast running more than five degrees above normal and ENFEN scientists drawing direct comparisons with 1997 and 1998. The Peruvian government has already responded with a formal Emergency Decree published in El Peruano, authorizing 60 days of emergency interventions specifically to address imminent risks from El Niño 2026-2027 precipitation.
The Mantaro Basin: Ground Zero for Peruvian Power
The single most consequential zone is Peru's central region. 71% of installed hydroelectric capacity is concentrated there, including the Mantaro River basin, which alone hosts 25 generating plants.
History provides a precise preview. During a previous huaico season in Huancavelica, the Mantaro complex closed its water intakes as a precaution against sediment, cutting output by 300 MW in a single day and causing rolling blackouts that affected roughly 10% of national supply for several hours. With an extraordinary El Niño now projected — one that scientists say may exceed 1997 levels — that scenario could play out repeatedly across an extended summer.
The pattern has precedent: during earlier huaico events, Enel Generación Perú was forced to suspend operations at the Huampaní, Callahuanca, Moyopampa, and Matucana plants simultaneously, while Huinco reduced to a single generating unit. For 2027, the number of plants in comparable situations could be far larger.
Who Pays When Hydroelectric Output Falls?
The answer depends entirely on which side of the market you sit on.
Peru's regulated electricity market, which covers over 8 million residential and small-commercial users, has tariffs set by Osinergmin — making those consumers structurally insulated from short-term wholesale price spikes.
The exposure falls squarely on the free market. Peru's roughly 3,000 large industrial clients — mining companies, shopping centers, manufacturers — contract their supply directly with generators, which means spot-market price movements feed straight into their energy costs. These free-market clients represent approximately 60% of total electricity consumption in Peru, even though they are few in number.
The energy sector has already been identified by risk management firm Gallagher as one of the five sectors most exposed to El Niño impacts, alongside agriculture, fishing, transport, and construction. The firm warned specifically about higher water flows damaging hydroelectric infrastructure, compounded by rising demand for air conditioning during heatwaves — a combination that can push the grid toward overload and service interruptions.
International Ratings Agencies Are Watching
The exposure is not limited to Peru's borders. Moody's Ratings issued a study warning that a severe 2026–2027 El Niño will disrupt precipitation patterns across Latin America and directly reduce water availability in countries that depend heavily on hydropower — listing Peru alongside Colombia and Brazil as the most exposed markets. The agency flagged that weaker hydroelectric generation would increase reliance on gas-fired power and even diesel in stressed conditions, raising spot-price volatility while testing fuel-supply and transmission infrastructure.
The Banco Central de Reserva del Perú already incorporated a strong El Niño Costero into its June 2026 macroeconomic assumptions, estimating the climate event could subtract between 0.7 and 0.8 percentage points from GDP growth in 2026 and between 0.8 and 0.9 points in 2027. Since those projections were published, ENFEN has upgraded the expected magnitude to extraordinary — the highest classification — suggesting the economic impact factored by the central bank may itself be an underestimate.
The Cost of Inaction
Peru generates more than 50% of its electricity from hydroelectric sources, which means even a partial disruption to the network of plants feeding the Sistema Eléctrico Interconectado Nacional forces a costly shift toward thermal and diesel generation. Those substitutes burn fuel; fuel has a price; and that price lands on someone.
The lesson from 2022–2023 is concrete. When hydroelectric generation fell to roughly 32% of total output during the drought that year, diesel generation climbed to nearly 8%, and spot market prices reached close to US$180 per MWh — more than five times the historical average. Midsize and small companies with contracts indexed to spot prices absorbed the shock directly. Energy analysts tracking the current El Niño cycle now project that a repeat event of extraordinary magnitude could push spot prices toward US$250 per MWh — 40% above what the market experienced in 2023.
For the 2027 summer, the question is no longer whether El Niño will affect Peru's grid. With close to eight million Peruvians in Cenepred's very-high-risk flood zones — concentrated in Lima, Piura, La Libertad, and Lambayeque — and dozens of generating plants sitting inside the same risk corridors, the answer is structural preparation or an expensive bill that may set records.
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