Aqueduct
plants

One important sector for the development and application of renewable energy involves the placement of hydroelectric turbines along networks of aqueducts and irrigation systems. These installations can exploit differences in heads and flow rates occurring in existing infrastructure, such as pipelines and canals. In addition to the production of electricity using potential energy that would otherwise be lost, this system also has a lower environmental impact because it exploits existing infrastructure.

As specialists in this sector, LUMIEI Impianti has delivered numerous aqueduct installations and has now designed and fitted out a test laboratory at its Sauris premises, where plants are built to scale to simulate the future installation and to study the behaviour of the turbine under different working conditions.

Potable water is normally sourced from high attitudes and conveyed to users through a network of pipelines. Often the geodetic head produces a supply pressure that is too high for some uses. In such cases, special devices are used to dissipate the excess pressure. The potential energy from the dissipation process is usually lost, unless a hydraulic turbine can be installed to exploit it. By using a deviation from the aqueduct or installing a turbine generator directly at the point of dissipation, electricity can be produced. To ensure a continuous supply of potable water an automatic bypass is installed in the plant (see figure below). All the organoleptic properties of the water is preserved, since the parts of the turbine that come into contact with it are made from certified food-grade materials. Moreover, mechanical parts are driven solely by electric and/or pneumatic actuators, and rotating parts are not lubricated. Several hydroelectric plants with similar characteristics can also be installed where the overflow from reservoirs in the aqueduct system can be redirected to harness flows which would otherwise be dissipated.

The main advantages of this type of installation can be summarised as follows:

• Recovery of potential energy which would otherwise be dissipated
• Streamlining of aqueduct water supply systems
• Additional revenues from electricity production to those from supplying of household water
• Diversification of business for water companies
• Possible cost containment for lifting and/or purification plants, thanks to self-produced electricity
• Environmental mitigation and containment of construction costs, thanks to exploitation of existing facilities
• Environmental awareness-raising around renewable energy and the exploitation of existing resources, with a focus on environmental mitigation in electricity production