The Benefit Of Electric Turbo Compounding Technology

Louise Smyth

Bonnhoff Buchenhof Bioenergie (Bonnhoff) operates two sites in Germany that perfectly meet the needs of the circular economy, with a key focus on recycling and sustainability. 

Since 2006, Bonnhoff has provided renewable electricity to the public grid. In addition to using its 440 hectares of agricultural land for growing crops, it uses a digestor to turn any waste into biogas. This biogas is then used to generate power across four combined heat and power (CHP) plants.

The excess heat is used by a local school, gymnasium and fire station, along with Kordes Rosen, the largest rose nursery in Europe, which heats its greenhouses and outbuildings.

The Brief

Keen to reduce its fuel consumption and emissions, Bonnhoff sought out Bowman to explore how its Electric Turbo Compounding (ETC) technology could help the company achieve this goal.

Bowman had already installed over 400 ETC systems in Germany, more than in any other country. When combined with its experience with biogas engines this made the company an ideal choice of supplier for the project.

It was agreed that Bowman would initially fit its ETC 1000 engine efficiency system on a Jenbacher J312 engine at one of the sites.

The key requirements were to: reduce fuel consumption; reduce greenhouse gas emissions; must have compact footprint; and conduct testing pre and post installation to assess performance

Installing The Electric Turbo Compounding (ETC) Technology

In March 2019, Bowman appointed Storm-Group with exclusive rights to sell and install the ETC 1000 system in Germany. As the largest OEM-independent service company in Germany for combustion engines, Storm-Group provided Bowman with increased resources and sales support in the region.

Under the agreement Wulf Johannsen (member of the Storm-Group) and Bowman worked together on the installation at Bonnhoff, allowing Bowman to pass on its expertise for future installs.

With the engine located in a small room the space presented logistical challenges. These were overcome through planning and engineering work before the installation, along with cooperation between all parties on site.

Thanks to this cooperation the installation was seamless, with testing completed in just a few days, covering both baseline testing and results post installation.

The Benefits Of ETC

By improving power density and fuel efficiency, fuel consumption was reduced by 5.7%, along with a reduction in associated CO2 and NOx emissions. Volatile organic compound (VOC) emissions were also reduced by 30%, through reducing fuel short circuiting.

The combined CO2 equivalent effect of these changes was an 18% reduction in greenhouses gases, and 12,000kWh of power generated without any extra emissions being created. Following successful initial results Bonnhoff agreed for Bowman and Storm-Group to use the site for a customer showcase to demonstrate the system to German prospects, where it received a strong level of interest. The two companies have also continued to strengthen their relationship, promoting the ETC 1000 technology through the Wulf Johannsen brand at the third Norddeutscher Biogas-Branchentreff event in Rendsburg, Germany.

“I have been very pleased with the results from the ETC 1000 system, with some highly promising initial gains in efficiency and reductions in emissions,” comments Bjorn Bonnhoff.