They can always be dismantled if a better way of generating power is discovered.
For that reason the news that Meridian Energy has confirmed plans for a 31-turbine wind farm in Ohariu Valley is welcome. The farm, on exposed coastal land, is projected to generate 71 megawatts of power, enough for 35,000 homes, and is in addition to Meridian's 62-turbine West Wind project at Makara.
It is also additional to the Puketiro project near Pauatahanui where British firm Res New Zealand is seeking permission to erect up to 50 turbines that will be visible from as far away as Island Bay and Waikanae.
As well as producing environmentally friendly power, all the projects will create extra jobs and bring extra money into the region, particularly during their construction.
The Ohariu Valley scheme has the added advantage of making more economical the five farms on which the turbines will be erected.
Nevertheless, all three projects have attracted criticism. In the case of the latest it has come from Ohariu Valley residents who object to the widening of upper Ohariu Valley Road to allow heavy vehicle access.
The change will, in the words of one, turn the road "into a boy racers' dream". There are also concerns about increased traffic and the demolition of historic community cattleyards on the corner of Ohariu Valley and Boom Rock roads.
At Makara locals have objected to encroachments on their views and the noise from turning blades.
Similar concerns have been raised about the Puketiro development.
Those genuinely affected have a right to fair and reasonable compensation for inconvenience caused and lost enjoyment of their properties. In most cases the simplest solution will be for the developers to buy their homes from them.
But the affected residents do not have a right to stop vitally needed infrastructural developments.
It is not just hot showers and plasma screen televisions that are at stake. Homes, schools, hospitals, offices and factories all require power to operate.
For New Zealand to keep growing, and to keep meeting the expectations of its citizens, it has to keep finding new sources of electricity.
At present, wind farms are the most environmentally sensitive way of doing that. Until a better one is found, wind projects are to be encouraged.