Powerlines serve for electricity the same function that pipelines serve for oil and natural gas. They often produce similar ecological impacts, including habitat fragmentation, and are an aesthetic blight on landscapes. The expanding network of transmission lines has resulted in linear clearcuts through ecosystems around the globe.
Electricity has two drawbacks that oil, natural gas, and coal do not have. It does not exist in nature in a way that humans can harvest directly (we must convert other energy into electricity), and it cannot be stored easily. Yet it is electricity—providing power to illuminate the night and run myriad machines from cell phones to computers—that we most equate with modern society. Electricity consumption tends to grow steadily in developing economies, even while the underlying sources of that electricity (i.e., coal, nuclear, and natural gas) may shift over time. Power lines play the crucial role of transporting the electricity from the point of production to the point of consumption.
Power lines are typically categorized in two groups. Transmission lines are high voltage lines used to carry electric current from generating stations to consumption hubs. From hubs, where the current is downgraded to house current, distribution lines deliver electricity to the point of consumption.
Power lines can have the same fragmenting effects on wildlife habitat as pipelines. High voltage power lines are allotted a 120-foot right of way (60 feet on each side of the transmission tower) to ensure that the lines are unobstructed from vegetation. This allows companies to clear-cut all natural vegetation within that distance. Clear-cutting forests and other vegetation for pipelines and to accommodate power distribution networks has fragmented forest ecosystems around the world, with substantial impacts on ecosystem integrity. The variety of “edge effects” from such fragemention, particularly the invasion of exotics or weedy species and loss of interior forest habitat, is well described in the scientific literature.
The aesthetic impacts of power lines are more difficult to quantify than ecological costs but are very real to affected communities. New transmission capacity is expensive to build and often highly controversial. There are numerous current campaigns under way fighting proposed power lines, from the “Northern Pass” project in New Hampshire that would bring additional HydroQuebec-generated electricity to the U.S. energy market, to the coalition of activists working to stop a new, roughly 1200-mile transmission line through southern Chile. That project, proposed in conjunction with a scheme to build multiple large dams on wild rivers in Patagonia, would bisect numerous national parks and national reserves to supply power to urban areas in central Chile.