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The world of photovoltaic energy is experiencing an unprecedented boom that is being driven by changes in legislation and the rising cost of energy. Companies specialising in this sector are tackling projects with enthusiasm, working intensively and participating in innovative projects. Water drainage is a particularly complex issue, especially during the autumn when rainfall is abundant. This, coupled with fluctuations in the sea level, means that a series of pumping stations are required to facilitate water extraction from the fields. The Comunitat de Regants-Sindicat Agrícola de l’Ebre, which is responsible for managing the water from the left channel of the Ebro for agriculture, was in need of a more efficient and environmentally sustainable management system.

One of its critical initiatives was the installation of an autonomous pumping station in the municipality of Deltebre to reduce the burden on the existing station at Pal and redistribute water to improve local habitats. The key to this installation was decentralisation and energy independence. This was achieved by designing a solar-powered photovoltaic system that involved the installation of 126 540 Wp solar panels close to the pump to maximise efficiency. The solar system’s peak power of 68.04 kWp feeds a 37 kW Controlvit variable frequency drive that supplies power to the 25 kW pump motor. This connects to an Archimedes’ screw, a pumping system suitable for liquids with suspended particles and known for its long service life, low maintenance costs and silent operation. The system also has an emergency generator and a remote system for distance monitoring and control.

Variable frequency drives installed in water pumps can reduce the motor speed from the outset, generating energy savings of up to 50%. In addition, the electronic control of the variable frequency drive helps to optimise its performance by adapting to the highly variable operating conditions of the pump, which, in turn, depends on the hydraulic supply requirements. This optimisation is achieved by varying – hence the name of the device – both the frequency and the voltage that supply the motor and regulate its speed. In other words, the pump’s motor always runs at the optimal speed.

The results so far are extremely promising, and the project in Deltebre is only the first of a series of similar installations planned for the left hemidelta. With an estimated payback period of approximately three and a half years, this project demonstrates that photovoltaic solar energy is not only cost-effective but also environmentally beneficial in such a fragile environment.

As an expert in power electronics with a high degree of environmental awareness, Salicru has developed variable frequency drives for solar pumping that combine all these attributes. Thus, the CV30-PVs use the radiation captured by solar panels to power the drive with direct current, which, in turn, supplies alternating current to a submersible pump. It also offers an integrated cabinet version, the ACV30-PV, with automatic switching and booster options.