The lights could go off in Haast within a decade, the town's hydro-electricity operator warns, amid fears new laws will make rebuilding the scheme near impossible.
Currently, all hydro-power schemes have 35-year consents to use water.
Under the Natural and Built Environment Bill, one of three pieces of legislation to replace the Resource Management Act, that stays the same for the large generators connected to the grid, but is just 10 years for smaller schemes.
Haast is supplied by its own run-of-river hydro scheme on the upper Turnbull River. The national grid stops 50km away, at Paringa.
If the new Bill is enacted, the existing Turnbull scheme would have to have its consents renewed every decade once the existing consents expire.
Owner David Inch, of NZ Energy, said Haast actually needed a new scheme down river within five to 10 years, with the advent of electrification plus normal growth.
He has started planning for that but with consents limited to just 10 years, it would be impossible to get financial backing.
Mr Inch said if it came to it, "the lights could go off in Haast".
They could instead bring in diesel generators, which in turn could power the electric cars in town — a "ridiculous scenario."
"We aren't going to run Haast on solar."
The Turnbull power scheme has been operating for 50 years.
Mr Inch said he now faced the cost of re-consenting, and specialist reports needed for that could blow out to as much as $50,000.
