Photovoltaics make water treatment "greener"

The roughly 1.4 million inhabitants of the Brussels capital region produce around 275 million litres of wastewater every day. An annual total of 182 MWh is needed to treat this volume of water in the Aquiris treatment plant. To ensure that this energy is generated in the most environmentally friendly way possible, hydroelectric power and biogas production were recently supplemented by a photovoltaic system on the roof of the wastewater treatment plant. Together, these three technologies now cover a quarter of the overall electricity required for treating the wastewater.

Continuous performance transparency

Three 1 MW inverters from the Finnish manufacturer VACON® provide a clean supply of energy into the national electricity grid. A crucial advantage here is the "Multimaster" concept with which VACON® ensures that the photovoltaic system always generates the maximum output in line with the sun's intensity at any given time.

There is always high transparency in regard to the system status and electricity generation of the inverters. Thanks to remote monitoring and communication via Modbus TCP/RTU, the operator can track the output profile online and receives notifications of the latest developments via SMS text messages. Downtimes can therefore be minimised efficiently.

Monitoring of individual strings

Within the framework of this monitoring, the 60 combiner boxes that VACON® sourced from Weidmüller play a decisive role. Installed between the solar modules and the inverter, they interconnect the electricity generated. This allows the power intensity of individual strings to be monitored for diagnostic purposes, so that low-output strings can be identified and serviced extremely rapidly.

"On the basis of recurring customer requirements, we have already developed numerous tried and tested configurations for photovoltaic systems. This is how we managed to fulfil the VACON® requirements directly with pre-wired combiner boxes," reports

Weidmüller managed to fulfil the VACON® requirements directly with pre-wired combiner boxes

Rudi Vanderstraeten, Industry Manager at Weidmüller, who advised VACON® during the project. "Thanks to the configuration of components for surge protection and string monitoring, our customer benefits from a holistic system solution that is particularly easy to implement in the existing SCADA topography. So not only is there clarity in water treatment, but energy generation on the roof is totally clear and sorted too."

Guests from the Land of the Rising Sun

A water treatment system that autonomously covers its electricity requirement in three different ways – this is definitely something special. In any case, it certainly impressed Weidmüller’s Japanese customers who visited the photovoltaics plant in Belgium.

“On a visit to our production facilities and in-house laboratory, we were able to give our guests from Japan a fairly good idea of the high quality standards we apply when we’re developing and producing our photovoltaics solutions. And the subsequent visit to Belgium served only to prove that our standards are continually upheld in application,” explains Klaus Holterhoff, Head of Weidmüller’s Application-Specific Solutions Division. “On the roof of the water treatment plant, the main focus was the installed combiner boxes, which we tailored especially to the plant’s specific requirements and its particular location.”

Japanese visitors get an insight into the installation of combiner boxes in Belgium

Clearly inspired by the photovoltaics solutions they examined, Weidmüller’s guests have already initiated some new projects of their own in Japan. Marubeni, for example, is relying on Weidmüller’s photovoltaics solutions, from the strings to the control room, in what is presently an 82 MW plant. By and large, the so-called “Land of the Rising Sun” is one of the most important markets for solar energy. Indeed, the generation of solar power is a highly relevant national project for the fifth-largest consumer of energy in the world.

You might also be interested in:

Products and solutions for photovoltaic systems

Combiner boxes: perfect solution for individual requirements

Interview: "Increased focus on renewable energies"

Published in April 2015