Filtrelec® is a technical and economical field-proven solution for photovoltaic power plants to fully comply with Clean Water Act requirements


Since its launch a few years ago, more than 2,000 Filtrelec® filters have been installed in photovoltaic power plants around the world. It is now the reference point for power station environmental protection.

One of the biggest risks of pollution in photovoltaic power stations is linked to the presence of dielectric oil used to cool and isolate the electrical transformers in PV power stations. With the continuous increase in the power capacity of PV power stations, the number of power stations is increasing, as is the risk of pollution.

Whether due to a small leak of oil from the transformer or a full oil spillage, zero risk does not exist. To prevent ground pollution from transformer oil spillages, power station construction standards require a retention bund to be installed underneath the transformer capable of absorbing at least 100% of the transformer oil. However, when the power station is installed outside – and in the event of rain – the retention bund will fill with water and its retention capacity will decrease.

In order to resolve this technical issue and avoid building an expensive water/oil physical separator, the French company GMT International (the parent company of Akhelec) – in cooperation with the French Institute of Petroleum and French petroleum industry leader Total – has developed a hydrocarbon filter that can be connected to electrical transformer retention bunds.

The function of the filter is twofold: To continuously drain rainwater outside the transformer retention bund while at the same time absorbing every trace of hydrocarbon. The amount of hydrocarbon contained in the released water is always less than 5mg of oil per litre of water (5 ppm) in full compliance with Clean Water Act requirements.

Secondly, in the event of a massive oil spillage in the retention bund, the filter active media automatically solidifies and creates a plug inside the filter. No oil nor water can flow outside the bund and the pollution risk is fully contained.

Constantly aiming to innovate and improve its product ranges, GMT International released the latest version of its Filtrelec® filtration system onto the market in 2018. It is lighter, more resistant to extreme temperatures and to UV [ultraviolet] and produces reduced quantities of waste.

This latest version of the Filtrelec filter makes maintenance operations easier and much cheaper for photovoltaic power plants.