Space Shout [lack of] Use

I'm 5/6 days into my first playthrough, just ambling along the main quest line while doing a lot of faction and side quests. I'm nearly to level 50, and I've never used any of the 'shouty' powers. That's partly because I haven't needed them yet, but also because I haven't really figured out how to trigger them. Are they that useless, or am I doing something wrong? I do remember using the shouts in Skyrim occasionally.