Rainer Helmig was interviewed by Dr. Ing. Hildegard Lykko for the April issue of the magazine gwf Wasser | Abwasser:
"Gefährden unterirdische Energiespeichersysteme das Grundwasser?" (pp 22-25)
An English Version was published as well in the magazine gwf Wasser | WaterSolutions in May 2022:
"Underground energy storage systems: a threat for the groundwater?" (pp 28-31)