Water

Water

The responsible use of water resources and their protection is vital to safeguarding natural ecosystems and enhancing the wellbeing of people that live in them, as well as to the success of our activities. That is why this issue is one of the strategic goals of our environmental policy, which pursues an integrated approach to optimize water management.

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0.20
l/kWh specific water extraction
22.9%
water withdrawn in areas of water stress
51.5
Mm3 total withdrawal of process and closed-cycle cooling water

In order to ensure that water resources are used and managed sustainably, Enel has identified three key guidelines:

 Efficient use of water resources, reducing water needs in all its production processes and, where possible, promoting internal reuse, especially in areas where water is scarce (areas of water stress).

Wastewater treatment optimization and water quality conservation of the destination environment, by adopting state-of-the-art technology and management practices, in full compliance with the limits set by applicable national regulations and operating permits.

Responsible and integrated management of hydro-geological basins to preserve multiple land uses and water quality.

Enel has launched a number of projects with regard to the responsible management of water resources. The aim is to map the needs and the sources of water withdrawal at all its production sites, whether thermoelectric or renewable,in order to set new targets for reducing the water footprint by planning a series of innovative improvement measures, with particular reference to water-stressed areas.

Enel has also implemented a number of projects at its hydroelectric power plants. These support a responsible and integrated management approach towards the hydrogeological basins in order to preserve multiple land uses and water quality.

 

Innovative HYDRO projects

Water as an economic and social driver

Noguera Pallaresa is a river in north-eastern Spain that runs from the Pyrenees Mountains into the Segre, a tributary of the Ebro. The river flows through Pallars Sobirà county in the province of Lleida (Catalonia), a region with a strong vocation for tourism, particularly in active tourism, water sports and adventure activities. These

sports have developed successfully, thanks to the optimized regulation of water flow from basins at the hydroelectric plants managed by Enel-Endesa on these rivers (Torrassa and Llavorsí, 10 MW and 52 MW, respectively). This ensures that these sports can be practiced safely and continuously throughout the tourist season, and that the region can host sports competitions and events, including at national level. 

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Regulating water for recreational and social use requires continuous monitoring of hydroelectric plants and their hydraulic infrastructure, together with a reliable communication system between installations along the Noguera Pallaresa and the Control Center, which is located in Lleida. The Control Center is continuously developing models to assess the required water flow rate, taking into account the orography (the study of the topographic relief of mountains), the river’s current flow conditions, reservoir storage levels depending on seasonal weather conditions, electricity generation needs and additional services provided, such as irrigation and water supply to the population. This complex assessment determines, in a fully automated and remotely controlled process, the volume of water released through the hydroelectric turbines, making the recreational and social use of the river compatible with the simultaneous generation of 100% renewable electricity.

WaVE Project

“Waterless” washing of photovoltaic panels in Peru and Chile

The Rubí solar power plant (145 MW) is located in the Moquegua district of Peru, in an area classified as high water stress and at an altitude of 1,481 meters. Efforts were made to reduce the withdrawals of water used to clean the panels by implementing software that measures the loss of efficiency of each panel in order to estimate dust deposition and programs washing priorities.

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A form of dry technology was selected for the periodic cleaning of the panels, whichuses mechanized brush systems, thus reducing water washing to once a year. In order to meet these water needs, a device was installed that condenses air moisture to produce the required amounts of water. By implementing these solutions, with five dry cleaning cycles and only one air-condensed water cleaning cycle planned over the year, the system is energy-efficient and completely independent of scarce water resources, which can be left to meet the priority needs of the local population. Enel has undertaken an equally important challenge at the solar plants in Pampa Norte, Lalackama, Finis Terrae and Chañares (totaling 358 MW), which are located on the Atacama plateau in Chile, a desert area at an altitude of between 2,400 and 4,200 meters. An innovation project was launched in the region in 2020 to capture water from the region’s typical night fog. This involved identifying the most suitable areas for recovering moisture and testing the performance of various capture technology solutions. The goal is to reduce to zero the use of natural water sources to clean solar panels and to produce surplus water that can be used by the local community. Another simple but brilliant technological solution implemented at all solar facilities in Chile was to change the positioning of solar panels at night: this is known as “solar night parking.” Having changed their inclination during the day to maximize exposure to the sun, the solar tracking plants are normally made park in a horizontal position during the night. International solar panel manufacturers integrate this configuration to reduce exposure to wind, which is considered the main risk factor for the system. But in the Atacama Desert, the greatest threat is the dust that collects on the panels, reducing their performance. Now, they are positioned at 45° for the night. This simple solution has significantly reduced material deposits and promotes self-cleaning that makes the most of the high humidity at night.

“Reuse water” is the watchword in thermal plants

The WaVE project requires all thermoelectric plants to commit to reducing their water use. This is in line with the continuous quest for new solutions for reusing more process water internally. The Santa Barbara power plant (392 MW) in Italy mainly uses water to operate its evaporative cooling towers. However, water can be reduced depending on levels at the San Cipriano dam, and the return of water to the body of water downstream can be limited by the need to contain rises in temperature, especially during low flow periods. The power plant adjusted the operation of its cooling towers by implementing a new treatment process for evaporative cycle water and an advanced control and regulation system to monitor and control the chemical and physical properties of reinjected water in real time. These measures have increased the number of cycles of concentration in the evaporative towers, reducing the need to add water by 15%, as well as in the flow of water discharged. 

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Similar initiatives are planned at the Pietrafitta (Italy) and Ventanilla (Peru) plants. The Mahón plant operates on the island of Minorca in the Balearic Islands, which are classified as a high water stress area on account of the scarce availability of natural resources combined with high population. The recent installation of nitrogen oxide (NOx) abatement systems at the plant, which require water to operate, could have increased its impact. The solution adopted was to reuse effluents from the nearby municipal wastewater treatment plant to inject into the emission abatement system, thus preventing withdrawal from scarce water sources and recovering effluents that would otherwise have been discharged into the sea.