Mothballed

The power plant was mothballed because of its outdated technology.

Source: tatoeba (2112220)

However, the one-of-a-kind aircraft spent eight years mothballed before being upgraded and returned to service, where it has been contracted out to various companies and governments.

Source: tatoeba (10792626)

Reopening the mothballed Platform 4 at Birmingham Snow Hill, for example, is a relatively simple and inexpensive proposition that will relieve some of the capacity constraints at Birmingham Moor Street.

Source: wiktionary