Brazil loses the equivalent of the energy generated by the Belo Monte dam in renewable sources

Brazil lives an energy paradox: while solar and wind capacity grows, a significant part of this electricity is discarded. Understanding why this happens and how to turn waste into value is vital for those interested in clean energy and efficient housing.

Brazil loses the equivalent of the energy generated by the Belo Monte plant in renewable sources: the extent of waste and its impact on everyday life

In 2025, the operational cuts applied by the National Electric System Operator resulted in the disposal of approximately 20% of solar and wind energy that could have been produced. In average terms, this meant around 4,021 MW over the year, a magnitude comparable to shutting down Belo Monte for 10 months. For those evaluating a solar roof, a condominium with photovoltaics, or a small wind generator, it is a clear warning: there is energy, but the system struggles to absorb it when it all arrives at the same time.

Data compiled by Volt Robotics show that on at least 16 days the system operated close to the safety limit due to excess supply during daytime — a scenario much more critical than in 2024, when there was only one day at this level. The risk increases on weekends when industry and commerce reduce consumption, but solar production remains high. On Mondays, the curtailment due to excess hovers around 1,040 MW average; on Sundays, it spikes to about 5,135 MW average. The picture is paradoxical: there is excess energy during the day and a shortfall in the early evening, forcing the activation of thermal plants.

To gauge what is being lost, the consultancy estimated concrete equivalents. The curtailed electricity could have supplied, for a year, the entire fleet of electric vehicles in the country (around 600 thousand units) or kept 40 large data centers operating for the same period. In terms of households, we are talking about a monthly consumption of approximately 16 million homes. This is not an abstract number — it is the difference between light and blackout, between stable rates and rising costs, between efficiency and waste.

From the perspective of architecture and environmental comfort, this mismatch affects project and operation decisions. A building with high thermal inertia and automation allows for “charging” cold (or heat) when energy is abundant and cheap and releasing this reserve at peak times. On the other hand, a condominium without a demand management strategy inadvertently contributes to the “mountain” of consumption at 6 PM, when the sun sets and the system calls for help. Do you see how the way electricity is used weighs just as much as the generation technology?

There is also the systemic cost of curtailment: estimated losses of R$ 6.5 billion in 2025 for generators that were forced to stop even with signed contracts. This imbalance stifles investments and generates regulatory disputes because someone has to pay the bill — and, in the end, it tends to spill over into the tariff. The lesson is clear: renewable energy is excellent, but it needs flexibility, storage, and smart price signals to turn into real comfort, lower bills, and fewer emissions.

If the above photograph shows the extent of the problem, the next step is to understand the causes in depth to act precisely at home, in condominiums, and in cities.

Why Brazil wastes energy equivalent to Belo Monte: curtailment, daytime oversupply, and grid bottlenecks

The heart of the problem lies in curtailment, the controlled reduction of generation to prevent supply from exceeding demand at dangerous levels. The ONS applies this practice to preserve system stability, as imbalances can lead to widespread outages. In a country that has added solar and wind capacity at an accelerated pace, especially in the Northeast and Central-West, the daytime production curve has turned into an “uppercut” of energy that doesn’t always find consumers — or a way to flow to load centers.

Distributed generation (GD) currently has more than 42 GW of installed capacity and is expected to reach nearly 50 GW by 2028. This energy, mostly coming from rooftops and small parks close to consumption, injects electricity “outside” of ONS’s direct control. Since there is no way to limit GD in real-time on a large scale, the cuts fall on the plants of the centralized system. Not surprisingly, the Ministry of Mines and Energy acknowledged that the issue has ceased to be incidental and has become structural, requiring new rules and coordinated solutions.

It is important to note a point of debate: entities in the GD sector argue that the installations off the centralized grid do not solely account for curtailment, as they represent less than half of the country’s wind and solar capacity. They argue that the problem lies in the disorganized growth of centralized generation in areas without robust grid and the slow expansion of transmission. The two perspectives are not mutually exclusive. If the grid does not keep up with the speed of new generation — whether centralized or distributed — electric “congestion” sets in.

Besides the grid, there is the demand dynamics. On weekends, the closure of factories and shops decreases consumption while solar production continues at full steam. The result is surpluses at noon and steep ramps in the late afternoon when the system needs to ramp up firm generation. This daily “valley” and “peak” impose costs, including the activation of thermal plants to maintain voltage and frequency as the sun goes down.

The ONS and Aneel are discussing relevant regulatory adjustments: greater controllability of GD, storage auctions, more dynamic tariffs, and incentives for new energy-intensive loads (like data centers) to consume the daytime surplus. The Operator reminds that the effects are gradual and depend on structural and behavioral factors. In other words, engineering and regulation go hand in hand — and consumer behavior closes the equation.

For those designing or operating buildings, the synthesis is practical: if the grid struggles with peaks and valleys, buildings and neighborhoods can act as “buffers,” consuming more when there is surplus and less at peak times. This is the guiding thread for the solutions in the next section.

Solutions to capture wasted energy: storage, time-of-use tariffs, and consumption flexibility

When there is excess energy in the middle of the day, the ideal is to store and defer some use to the early evening. This can be done with grid-scale and building batteries, with hydroelectric plants acting as batteries through pumped storage, and with demand management that shifts consumption timings.

Battery storage and “hydroelectric plants as batteries” 🔋

Battery auctions being studied in the country are likely to stimulate utility-scale and hybrid (solar + battery) projects. In condominiums, lithium-ion or lithium iron phosphate banks can shift loads for air conditioning and elevators. In regions with reservoirs, using daytime energy to pump water back increases nighttime flexibility, transforming hydroelectric plants into large accumulators. These are investments with significant CAPEX, but with systemic benefits: less curtailment, fewer thermal plants, and more stability.

Time-of-use tariffs and load automation ⏱️

The expansion of time-of-use tariffs sends a simple price signal: cheap energy during the day, expensive at peak. With automation, you can schedule boilers, chillers, irrigation, and vehicle chargers to operate during advantageous windows. Even where flat tariffs are limited, special contracts and demand response programs already signal economic efficiency for those adapting the consumption profile.

Smart charging for electric vehicles 🚗

If the entire fleet connects at 7 PM, the problem worsens. The solution is to adopt “solar-friendly” charging: prioritize 10 AM–4 PM, offer discounts in business garages, and use software that distributes power among parking spaces. For fleets, “opportunity charging” throughout the day and stationary batteries can avoid nighttime peaks.

• 🌞 Anticipate thermal consumption: cool/heat spaces before peak and utilize the building’s inertia.
• 🔋 Install modular batteries: start small (20–100 kWh) and expand as savings prove themselves.
• ⏱️ Schedule loads: laundries, pools, pumps, and EV charging during high solar hours.
• 🧠 Automation: use controllers that respond to price, irradiance, and building demand.
• 🛰️ Monitoring: measure generation, consumption, and load factor to correct paths monthly.

To assist in planning, the table below summarizes measures, impacts, and technological maturity.

When these pieces combine — storage, pricing, automation, and new loads — waste transforms into useful energy. Want a first step? Schedule today the “shiftable” loads of the condominium for solar hours and measure the results for a month.

Costs and opportunities: billion-dollar losses, system security, and the chance for a new electric economy

Curtailed energy is not just a technical inconvenience; it has cost and influences investments. It is estimated that losses for generators reached R$ 6.5 billion in 2025, as plants with firm contracts were forced to reduce production. As the delivery commitment remains, the generator may have to buy energy from third parties, turning “undelivered” renewable energy into a financial liability. This generates insecurity and can delay plants, lines, and component factories.

There are advances under discussion: a recent law provides compensation in certain situations, and the Ministry of Mines and Energy has opened public consultations to structure mechanisms for reimbursement and specific flexibility auctions. Sector entities, such as Abeeólica and Absolar, argue that a clear framework will “unlock” investments. Without predictability, projects remain on hold. With rules and a revenue signal for flexibility, niches such as hybrid plants (solar + wind + battery) and contracts based on capacity, not just energy, emerge.

Another focus is the attraction of new energy-intensive loads. Data centers, for example, can anchor daytime consumption — and the country is already seeing movements in this direction. In regions with solar surplus, green hydrogen and desalination factories can also act as energy “sponges,” consuming when there is excess and reducing when the system peaks. This creates jobs, stabilizes tariffs, and gives productive purpose to the energy that is currently scarce.

For consumers and building managers, the opportunity is to reduce operational costs with contracts that value off-peak consumption and adopt demand response. Corporate buildings have been signing agreements with aggregators to decrease load between 6 PM and 9 PM in exchange for remuneration. In multi-family housing, cold storage facilities, pool pumps, elevators, and common area lighting can compose a portfolio of flexible loads managed by software — with alerts and monthly targets.

An illustrative case: the “Residencial Aurora,” an 18-story building in the Northeast, installed 80 kWp of solar, 60 kWh of batteries, and simple automation. The strategy was to cool common areas between 11 AM and 4 PM, charge the battery during that period, and schedule elevators in energy-saving mode at peak times. Result after six months: 23% reduction in peak demand and 12% drop in the bill, with no loss of comfort. The added gain? Less stress on the local grid, helping the system absorb the neighborhood’s solar energy.

At the national level, the message is pragmatic: the waste equivalent to Belo Monte can turn into industrial competitiveness, lower bills, and cleaner air, provided that flexibility is compensated for and the grid is planned alongside generation. The next step is to bring this into your homes.

How to adapt residences and condominiums: practical steps to use the energy that is already available

Transforming waste into benefit begins at home. Below is a practical roadmap designed for residential buildings, horizontal condominiums, and small businesses that wish to align consumption with the solar curve and relieve the nighttime peak.

30-day plan to reduce peak and enhance solar energy use 🌞

Week 1: conduct a load diagnosis. List what is “deferable” (laundry, pumps, climate control for common areas), what is “critical” (elevators, security lighting), and what is “flexible” (EV garage). Implement basic circuit measurement and establish simple targets, such as shifting 20% of consumption from 6 PM–9 PM to 10 AM–4 PM.

Week 2: program automation. Timers and Wi-Fi controllers can solve much of the issue: water heating, pool filtration, and cold storage should operate more during the solar period. Introduce comfort rules: cool lounges and receptions before the peak using thermal inertia.

Week 3: adjust EV charging policy. Establish differentiated internal rates by hour and incentives for those charging between 10 AM and 4 PM. If possible, implement dynamic balancing: divide power among active parking spaces, prioritizing windows with higher photovoltaic generation.

Week 4: evaluate modular batteries and a PPA (power purchase agreement) with time-based pricing, if available. Batteries of 20–100 kWh can significantly change the game for mid-sized buildings. With a contract that reduces daytime energy costs, automation can start “pursuing” price, irradiance, and local demand.

1. 🔍 Quick audit of loads and weekly targets.
2. 🕹️ Automation of non-critical equipment.
3. 🔌 Smart charging policy for EVs.
4. 🔋 Initial battery and expansion based on returns.
5. 📈 Monthly monitoring with fine adjustments.

For inspiration, seek practical and technical references. The following curation helps dive into storage and consumption management.

At the end of 30 days, repeat the measurements and consolidate a “before and after.” The goal is clear and measurable: reduce evening demand, increase the use of local solar energy, and prove that comfort and efficiency go hand in hand. If you’re going to take a single step today, conduct the load inventory and determine which three devices you can shift to midday.

Source: www1.folha.uol.com.br