Blauer Turm, Industrial research tower in Herten, Germany

The Blauer Turm in Herten is a steel-framed synthesis tower wrapped in a blue mesh casing, named for the blue hue of the hydrogen-rich gas it was designed to produce. Planned as a 10-megawatt pilot plant on the site of the former Zeche Ewald colliery, it was to use staged reforming to convert renewable feedstocks, farm manure or biogenic waste into a combustible gas. Construction stopped in 2011 when the main investor, Solar Millennium AG, went insolvent.

The Dr. Mühlen GmbH & Co. KG patented process ran in a one-megawatt pilot plant in Herten from 2001 until its dismantling in 2006. A successor 10-megawatt plant, officially named "Blauer Turm", was to be built on the site of the former Zeche Ewald; the state of North Rhine-Westphalia funded it with 7.1 million euros, of which about 3 million were paid out before construction stopped. The project was abandoned in 2011 after the insolvency of Solar Millennium AG, majority owner of Blue Tower GmbH.

The name "Blauer Turm" refers both to the blue colour of the hydrogen-rich synthetic natural gas produced and to the cladding of the steel skeleton around the reforming tower, which project renderings showed lit blue at night. The project was funded with 7.1 million euros from the state of North Rhine-Westphalia, of which about 3 million euros had been paid out when construction stopped.

The Blauer Turm was never a finished building: the 10-megawatt successor plant on the former Zeche Ewald site was halted in 2011 when the main investor, Solar Millennium AG, went insolvent. Only about 3 million of the 7.1 million euros in state funding had been paid out. The earlier one-megawatt pilot unit was dismantled in 2006, so there is no tower to visit today.

The name "Blauer Turm" referred both to the blue colour of the hydrogen-rich synthetic natural gas produced and to the cladding of the steel skeleton around the reforming tower, which project drawings showed lit blue at night. The successor plant on the former Zeche Ewald site was planned at 10 megawatts, ten times the output of the first pilot.