Stretching for thousands of kilometers through Sweden’s forests, the cleared strips beneath high-voltage power lines look, at first glance, like exactly what they are: the price of keeping the lights on. Bare ground, felled trees, the hum of infrastructure.
But rare bumblebees are showing up here. So are threatened butterflies, and grassland plants that have quietly vanished from much of the Swedish countryside. How does one of the most utilitarian features of the energy grid become an unlikely refuge for species that have nowhere else to go?
An unlikely sanctuary hiding in plain sight
Power line corridors exist for one reason: to keep electricity moving safely from generation to grid. Vattenfall, like any transmission operator, clears the vegetation beneath its high-voltage lines on a regular cycle. Trees come down. Shrubs are cut back. The land is reset.
What nobody planned for was what grows back in between.
The repeated disturbance mimics something increasingly rare in Sweden: open grassland. Low canopy cover, disturbed soil, abundant light reaching the ground — these are precisely the conditions many threatened plant and insect species require. As Sweden’s traditional grasslands have been converted to farmland, forestry, or development over the past century, the species that depended on them have been quietly running out of places to go.
Researchers studying green infrastructure have come to recognize this dynamic. Power line corridors, despite their industrial origins, now function as connective tissue across the landscape — linear habitats threading through forests and farmland alike, linking fragmented patches of open ground. What once looked like an ecological wound turns out to function, under the right conditions, more like a seam.
Mapping 8,600 kilometers of hidden potential
Recognizing potential is one thing. Acting on it systematically is another. In 2017 and 2019, Vattenfall undertook a GIS-based analysis of its entire corridor network across middle and northern Sweden — roughly 8,600 kilometers in total.
The goal was straightforward: identify which sections might already harbor, or could support, meaningful grassland biodiversity. The analysis flagged 1,600 kilometers as potentially valuable habitat — a substantial fraction of the network, but one that still needed ground-truthing.
Field teams followed up with biodiversity assessments across the identified areas, documenting habitats and species on the ground and ultimately classifying 980 specific sites covering approximately 250 kilometers. This granular work allowed Vattenfall to validate which areas were genuinely ecologically significant and to prioritize them for targeted management. The result was a data-driven map — not just of infrastructure, but of conservation opportunity. For a company whose primary obligation is reliable power transmission, that map represented a meaningful shift in how the corridors could be understood.
Rethinking the chainsaw: tailored maintenance for wildlife
Standard corridor maintenance follows a fixed rhythm: power line corridors cleared every eight years, patrol paths every four. That schedule exists for safety and reliability reasons, and it isn’t going away. The question Vattenfall began asking was whether the how of that maintenance could be adjusted to serve biodiversity goals alongside operational ones.
The answer, increasingly, is yes.
Insights from the mapping work led to tailored maintenance plans for individual high-value areas. Techniques vary by site. The toolkit includes creating glades to open up additional light, widening patrol paths to expand low-canopy habitat, removing cut material after clearing to prevent nutrient buildup that would favor aggressive plant species, and selective thinning to keep the canopy from closing between scheduled clearings.
Each measure is calibrated to benefit the species most at risk — bumblebees, wild bees, and butterflies, pollinators that have declined sharply across Europe as the open, flower-rich habitats they depend on have contracted. By 2025, 85% of the corridors identified as high-biodiversity areas had tailored maintenance plans in place. Vattenfall has set a target of 100% coverage by 2026. The shift is subtle from an operational standpoint. Ecologically, it represents a meaningful rethinking of what maintenance is for.
Early results: species are responding
Conservation programs often require patience before results become legible. Vattenfall’s corridor initiative is still in progress, but early indicators are encouraging.
During 2024 and 2025, follow-up inventories were conducted across 20 high-biodiversity areas to assess whether the management changes had produced any measurable shift in species composition and density. Compared to baseline data collected in 2018, the results indicate a higher density of species with conservation value.
The gains were most pronounced within the patrol path zones — the areas receiving the most intensive and targeted intervention. That pattern is consistent with what the management approach was designed to achieve: more frequent, more deliberate disturbance in the right places, producing the open-ground conditions that threatened species need. Researchers are careful not to overstate what the early data shows, but the signals are pointing in the right direction.
There’s something worth sitting with here. The infrastructure that fragments landscapes and clears forests is, under the right management, quietly becoming one of the more consequential conservation tools available at scale. Vattenfall didn’t set out to build a refuge for threatened bees. But 1,600 kilometers of corridor now suggest that the line between industrial necessity and ecological function may be thinner than it appears — and that what we build through the landscape might, with some intention, give something back to it.
