Comment by vidarh

Yeah, you're right regarding the environmental concerns.

Most of Norway's hydro dams were built a long time ago when there was little focus on the environmental effects.

The last major plant went live in 1993. Most of the focus now is on far smaller schemes, that doesn't really add up to a lot compared to Norway's established generating capacity (which outstrip the total electricity use anyway), but which also meet far less opposition.

Part of the reason for that was growing local opposition to larger plants, and sometimes national opposition, culminating with the Alta controversy[1] in the late 70's that were some of the largest civil protests in Norway since the end of WW2. The protests eventually failed, but it had a lasting effect on Norwegian politics.

[1] https://en.wikipedia.org/wiki/Alta_controversy