“We stand on the threshold of a new era,” he said. “We wish to take both sides into consideration in a new general framework that will accept environmental concerns as being as important as other concerns.”

Image Wild reindeer grazed recently near a road leading to the Karahnjukar Hydropower Project in eastern Iceland. Credit... Dean C. K. Cox for The New York Times

Sigurdur Arnalds, a spokesman for Landsvirkjun, the national power company, which is developing the Karahnjukar project, said: “Democracy will have the final say. Naturally, we will not build up every possibility we have; we have to stop someplace.”

Iceland is a prosperous country, but its prosperity is concentrated in Reykjavik. The government has long sought ways to bolster the economy by exploiting the country’s second- biggest natural resource, after fish: electric power, derived from a vast network of rivers and from underground geothermal fields.

But since the power cannot feasibly be exported, the idea has been to import demand. Aluminum seems a perfect fit. It is a power-intensive industry that needs easy access to ports for importing raw materials and exporting the finished product. Iceland has clean, available power, abundant coasts and proximity to the lucrative European market.

Iceland’s first aluminum plant was built in the 1960s; there are now two, both near Reykjavik.

“The government has done everything in its power to make way for these plants,” Kolbrun Halldorsdottir, a member of Parliament from the Left-Green Movement, said. “They have been fixed to this scheme like Saudi Arabia is fixed to oil. They don’t believe in entrepreneurship, job opportunities in our culture, tourism. They only believe in aluminum.”

The Karahnjukar project, years in planning, had the support of the center-right coalition government, which has been in power for 12 years. In opinion polls, the majority of Icelanders have consistently supported it, too, saying it would bring jobs and money to the eastern fjords.

But environmentalists say the project will devastate some 3 percent of Iceland’s land mass, destroying or affecting 60 waterfalls; causing widespread soil erosion that will send sand and dust blowing across the highlands and onto farms; and flooding an area covered in unusual moss and used by reindeer, nesting pink-footed geese and myriad birds, like the gyrfalcon and the ptarmigan.