How does one convert matter into energy?

I wish to make a device capable of opening portals and wormholes through time, but I found through calculations, to do such requires immense energy. And I was wondering, what could give me the energy. Mass. E=MC^2, meaning there is plenty of energy in one kilogram. So if anyone has an idea, please say. I can explain how mathematically and theoretically, one opens a wormhole. Thanks