Using green tea powder as an herb is a great idea.  Green tea adds not only antioxidants, but also “UMAMI (oo-mah-me)”, savoriness to the food.  Green tea antioxidants are also scientifically proven to reduce carcinogens in meats when they are cooked with high heat, such as BBQ.

There is an exhaustive list of green tea recipes for all occasions on this page.