Breakdown of Era un progetto tardivo, ma ne è valsa la pena.
essere
to be
un
a / an (masculine)
ma
but
il progetto
the project
Questions & Answers about Era un progetto tardivo, ma ne è valsa la pena.
In ne è valsa la pena, what exactly does the pronoun ne refer to?
Why is the past participle feminine (valsa) when the project (un progetto) is masculine?
Why does valere take essere (è) as its helper verb here instead of avere?
The verb valere takes essere in this expression because it is acting intransitively (it has no direct object). The subject is la pena, which is doing the action of "being worth." When valere is used without a direct object, it always requires essere in compound tenses.
Why does the sentence switch from the imperfect tense (era) to the passato prossimo (è valsa)?