So, Bolt was experimented with Terrigen when he was either a newborn or still in his mother's womb; this lead to him developong his powers at an early age, which ended up being the
manipulation of electrons. Electrons in the MU (according to Stan Lee and Jack Kirby) are magic molecules that let you do FUCKING ANYTHING. Including flight (manipulation of gravity electrons), turning living creatures to stone, forging light bridges, making objects out of thin air, physical enhancement, and electron energy blasts. Probably more.
As he got older, Bolt's powers caused electrons to attach themselves to the speech center of his brain. This meant that when he spoke, he was creating a massive explosion of electrons. He also had to use the forked antenna on his head to control the electrons that are attracted to him, otherwise the could overload his brain. Possibly killing him.
So yeah. BB's powers in a nutshell