Falling trees in conjunction with severe weather are the single biggest cause of power outages. Michael Wahl, head of high voltage operations at E.ON subsidiary Westnetz, explains how his company maintains a reliable energy supply while managing vegetation sustainably.
The conventional approach is reactive: simply accept the types of vegetation near power lines, let them grow until they get within about three metres of the conductors or other energized components, and then, after obtaining approval from the natural resources or forestry agency, cut them all down. This cycle would then run its course again. And again. This creates large open spaces and destroys ecosystems. The new approach is proactive, smarter, and more sustainable. For example, removing fast-growing trees like poplars and birch gives slower-growing trees like beech and oak as well as bushes access to more sunlight and thus the opportunity to flourish. This creates biotopes and new habitats.
Exactly. Having a slower-growing mix of trees not only lengthens the intervals between trimming, which saves us money. It also tangibly increases the biodiversity of both flora and fauna. We can further enhance biodiversity by leaving the cuttings on the ground when we trim, as long as doing so poses no hazard to the power lines or our operations. The cuttings provide nesting opportunities for small mammals, which may attract larger animals. Similarly, new wildflowers attract insects which then attract birds. In short, ECM is good for our business and creates added value for nature: it transforms a mostly monoculture forest into a rich habitat.
In 1992 when I was still responsible for high-voltage operations and maintenance in Westnetz’s grid territory in southwest Germany. A forester at Corporate Functions in Essen had chosen our grid territory for an ECM pilot project. I was initially sceptical because I felt the segments they’d targeted were too small, too far apart, and too topographically diverse for the forestry contractor to manage them cost-effectively. Over the next five to ten years, however, we expanded the size of the ECM zones, which made the approach economically and technically viable.
Having the right plan for the vegetation in a particular area and, just as importantly, having maintenance crews who understand – and buy into – ECM techniques. Employees and contractors need to be trained, and a few may need to be convinced. I’ve presented ECM to a number of grid operators outside E.ON. If management and crews embrace it, it’s usually successful. If they’re half-hearted, many run into difficulties. Ultimately, ECM is like any new process adopted by an organisation: belief and commitment are essential to success.
That’s right. ECM requires up-front investments: in surveying current vegetation, designing a plan to manage it, and training the maintenance crews. Those investments won’t be recouped immediately. It will take time before ECM’s advantages – like the longer intervals between trimming I mentioned a moment ago – to appear in a grid operator’s bottom line. But the savings in maintenance costs are real and should show up within three to four years. So maybe you just need a medium-term perspective.
Making an environmentally friendly approach to maintenance attractive from a business and operational standpoint as well. That Westnetz’s grid is robust and reliable even in severe weather is due in part to ECM. A storm may knock down trees, but they’re no longer tall enough to damage our power lines. So ECM not only lowers maintenance costs, it also reduces our expenditures to restore power and clean up after storms. Another achievement is the recognition we’ve received from nature conservation groups and other organisations. The German Nature and Biodiversity Conservation Union (NABU), Friends of the Earth Germany (BUND), Environmental Action Germany (DUH), and a number of universities have shown great interest in our work and want to see it adopted across Germany.
I’d really like to see ECM extended to all those segments of E.ON’s overhead power lines where it makes environmental and economic sense, initially in Germany and eventually in our service territories in other countries as well. All in all, we’re talking about thousands of hectares. It’s a huge opportunity. Our grids are becoming steadily smarter and thus even better able to accept more renewable energy and to orchestrate the complex energy flows of a decentralised energy world. At the same time, I think we should do our best to sustainably manage the biospheres under and near our power lines. In sum, I want E.ON to enable a sustainable economy while also being an exemplary environmental steward.
I do my best to conserve resources, which probably comes from my farming background. We tried to avoid waste and repair things instead of throwing them away. Conservation is in my DNA and affects how I work too. I do as much as I can digitally and look carefully for other options before I take a business trip. The restrictions brought on by the pandemic, however, made me realise that I actually hadn’t looked carefully enough and that there were even more opportunities to complete tasks virtually. I plan to continue making use of these opportunities even after the restrictions are relaxed.
Michael Wahl was born in Illingen, Germany, in 1963. He joined Westnetz in Saarbrücken in 1987 as deputy head of high-voltage overhead lines. In 1992 he received a bachelor’s degree in mechanical engineering from Saarbrücken University of Applied Sciences and was promoted to department head. Michael’s favourite part of his job is ECM. Outside work, his biggest hobby is carnival, a multi-week festive period before Lent celebrated in some parts of Germany. Michael is president of his carnival club’s board and helps plan numerous events. He and his family live in Heusweiler, which is located about 15 kilometres north of Saarbrücken.