Hydroelectricity, the perfect partner for integrated water use

Fresh water is a precious and indispensable resource for human life and for carrying out some of our main activities. Although 70% of the Planet is covered by water, only 2.5% of this water is fresh and much of it is found within ice caps and glaciers: the amount of water actually available is therefore far less. Considering the different uses, each inhabitant in Italy consumes 220 liters of water per day, which is well above the European average (165 liters). Agriculture in Italy absorbs about 60% of water resources, the industrial and energy sectors account for 25%, while the remaining 15% is the amount used for civilian purposes, which include personal hygiene and food. Furthermore, future water availability is not a foregone conclusion: climate change may result in scarcity or the irregularity of rainfall, especially in certain parts of the country, leading to difficulties in supplies. What is multiple use? It’s therefore easy to see that the careful and responsible use of the water resource will be increasingly strategic for a sustainable future. The concept of the multiple use of water, an issue increasingly on the agenda especially in hydropower, is a step in this direction. "With this definition," says Michele Verzillo, Global Management Support Manager for Hydroelectric Technology, "we mean the use of the same water resource for multiple purposes: drinking, irrigation and industrial. The reference legislation is the so-called Consolidated Environmental Act contained in Legislative Decree No. 152/2006, which determines the general principles of multiple use. The main concept is that the first and most important use of water is human consumption: in the case of a dispute, this use always prevails. This is immediately followed by irrigation use. In third place is industrial use, of which power generation through hydroelectric plants is a part." At a local level, there are also water management plans, managed by so-called Reservoir or River Basin Authorities, which aim to coordinate the various activities that use water with these priorities in mind and with a system of concessions. The same water, but more value and less pollution Under the regulations, then, hydropower plants never take water away from human or irrigation use: rather, they often further enhance this resource and provide useful community services. Unlike other industrial plants, hydropower plants do not have a significant impact on the quality of the water they use. This means that, when a drinking water treatment plant is installed downstream from a power plant, the same water that produced clean electricity can become a resource for that area by being fed into the aqueduct. Not only that, because of its characteristics, hydropower easily fits into the multiple use of water, in tune with the needs of agriculture. “Let’s take the case of a hydroelectric plant that’s positioned downstream from a reservoir which has been built for irrigation use: here, agriculture dictates the timing because the water drawn from the reservoir will be used primarily for this purpose, leaving the hydroelectric canal and power plant without water," Verzillo goes on to say. "Therefore the hydroelectric plant only works when the canal is active, but in that case the water that would normally end up downstream from the restitution is first used to produce clean energy, with a clear advantage in terms of sustainability." At Enel Green Power we use periods of plant downtime to carry out maintenance by flexibly managing the scheduling of activities in consultation with the authorities concerned. We also work side by side with the managing authorities when very long canals depart from a reservoir and cross cultivated areas. In these cases, depending on agricultural needs, all or part of the water can be diverted to the irrigation canal, prior to returning to feed the hydropower plant when possible. "This aspect is managed through continuous dialogue between our operations staff and the reclamation consortia. The water that isn’t used for hydropower generates refunds for the concession portion, but priority is always given to agricultural and, before that, civil use," Verzillo adds. In some cases, the presence of hydropower plants helps clean up reservoirs and streams. For example, reservoir water often contains waste that is caught through intake work and subsequently disposed of. Drought, extreme weather events: putting communities first "Activities like these are part of Enel's mission to support the communities where it operates," Michele Verzillo points out. "Unlike other industrial activities, our plants can be found all over the country, and we always try to put ourselves at the service of local communities. Just think, for example, of the canals that sometimes cross several municipalities before reaching a hydroelectric plant: in these cases, we reduce maintenance time to a minimum in order to give water back to farmers when they need it. Other cases involve the management of natural disasters such as drought and flooding. In the first case, we prioritize the use of all reserves, to provide water for citizens and for agricultural activity. In the second, in consultation with civil defense, we try to "laminate" the flood; in other words, to store as much water as possible at the most critical times in order to reduce the potentially catastrophic effect of a flood on the course of the rivers." Multiple-use policies are in fact already being applied at most of EGP's hydropower plants in Italy; however, we are also engaged in a continuous path of evolution in this field. This could also lead, in the future, to the use of wastewater – i.e., the water used in activities downstream from the purification process – to feed some hydropower plants, thereby further optimizing water resource management.

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Hydroelectricity, the perfect partner for integrated water use

Hydroelectricity, the perfect partner for integrated water use