When we moved to Munich, one thing that got me was Single-acting baking powder. As you thought, baking soda is the same as bicarbonate of soda. But bicarbonate means it can have two rises... and ultimately means the difference between single-acting and double-acting (what you get in the US) baking powder
. One dry acid (single-acting) or two dry acids (double-acting, or just regular baking powder in the US). Confusing, huh??
I still don't know when I need to use soda vs. single-acting powder vs. double-acting powder (which I haven't found here).