Since the caffeine in energy drinks likely doesn't come from EU and ppl drink it for that, you can just buy guarana and mix it in your own drink (i.e. grape or apple juice, which can come from EU).
However, be aware that pure caffeine (which is an alternative and is better soluble) is very potent and can easily be lethally overdosed as it is hard to measure such small amounts, while guarana can be dosed with a teaspoon as per the instructions on packages.