Mix boiling water and flax seed together in a bowl; set aside to thicken.
Combine oats, chia seeds, hemp, baking powder, bicarb and salt together in a large bowl; stir in agave nectar, coconut oil and flax mixture until well mixed. Fold chocolate chips into mixture; press into a 20x30cm baking tin.
Bake in the preheated oven until cooked through, about 15 minutes. Cool to room temperature and slice into bars. Chill before removing from tin.