Tannerite is very energetic, it is just a bit difficult to detonate.
Tannerite is just ammonia nitrate and powdered aluminum.
I doubt that we know just what the explosive used was, yet.
Tannerite is next to the bottom for explosives. It is not classified as a high explosive. It will take more than a pipe bomb or a pressure cooker to cause maiming unless you are very very close.
ANFO(Oklahoma City) is almost twice as powerful and still not classified as a high explosive.
http://www.usatoday.com/story/news/nation/2016/09/19/tannerite-explosive-bomb/90692338/