Story highlights Technicians from as far away as Montana are helping to fix Puerto Rico's broken power grid

Gov. Ricardo Rosselló has pledged most of his island will have electricity by December

San Juan, Puerto Rico (CNN) Power workers with no fear of heights are being hoisted up by helicopter in the mountains of Puerto Rico to repair the island's devastated transmission lines.

About 300 are in Puerto Rico already and 700 more are on the way, contracted by a fairly new company based in Montana, of all places.

Montana may be 3,000 miles from Puerto Rico and far from tropical, but Andrew Techmanski, the CEO of Whitefish Energy, says his workers and contractors have the skills needed to get the island back on line.

They're used to working in rough, mountainous terrain, dangling from a helicopter and clambering high up on transmission towers to get power lines up.

Linemen work to restore a key central transmission route.

Still, when the Puerto Rico Electric Power Authority agreed to a $300 million deal with Whitefish Energy without consulting the Army Corps of Engineers, it caused a stir.

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