Limnology and Water quality

Around 90% of the energy generated by FURNAS comes from hydroelectric plants, supplied by large reservoirs distributed along several hydrographic basins that extend over an area of 5560 km². The total volume is 127 km³.

In each of these reservoirs, the quantity and quality of water are systematically assessed by hydrological and limnological monitoring programs (relative to the scientific study of freshwater bodies), which provide fundamental data, such as: storage level, wastewater flow, nutrient contents and its biological productivity, concentrations of pollutants and bathing capacity. FURNAS monitors water quality and whether it is safe to use, both for supply and irrigation, fishing, navigation and leisure.


The company is currently developing the Research and Development (R&D) project "Water and Sediment Quality in Response to the Installation of Aquaculture Parks in the Furnas Hydroelectric Power Plant Reservoir", in partnership with the Support Foundation of the Federal University of São João Del Rei (FAUF).

Water use, reuse and collection

At the FURNAS operational units, the company seeks solutions to reuse water and also collect rainwater.

Santa Cruz TPP (RJ)

The water from the monovalve filters in the Santa Cruz Thermoelectric Plant (RJ) water treatment station is being reused, as pipes are being deployed to recover the water used in the Evaporative Coolers of Generator Units 11 and 21. With both projects underway, it will be possible to reuse approximately 180m³ of water per day, considerably reducing water loss in production processes.

SE Ibiúna (SP)

The water in this substation is reused for washing the vehicle fleet and maintaining the garden.

SE Jacarepaguá (RJ)

In 2017, FURNAS began a pilot project to reuse the water spewed by the air conditioners in the control room of the Jacarepaguá Substation by storing it in two 500-litre water tanks installed on site. The water is pumped into a 1000-litre box at the top of the building and distributed for use in toilet flushing, external cleaning and maintaining the garden. SE Jacarepaguá also has a laboratory studying reduced models, using water captured from the rain in its analyses. The reservoir has the capacity to collect up to 8,600 liters per year.

SE Tijuco Preto (SP)

At the end of 2016, two reservoirs were built using recycled deactivated hydro-pneumatic tanks and other materials that capture rainwater, totaling a 60,000 liters storage capacity. FURNAS now saves energy from submerged pump motors and decreases potable water extraction from artesian wells. The water is used to wash vehicles, roads, sidewalks and equipment.