TL= Turbolaser.
Full mathematical formula =
http://www.stardestroyer.net/tlc/Power/
"
Therefore, if we are conservative and use the melting point (more specific figure than boiling point), and use 20 meter asteroids, with the melting figure of ~30 TJ: a medium-sized TL bolt must have in excess of 450 terawatts of firepower.
When discussing a weapon, there is more than one way of expressing firepower. Turbolasers fire "bolts", so the firepower of each bolt can be measured. These bolts are only fired once per unit time, so the "sustained" firepower is the power of each bolt divided by this unit of time. These mid-sized TL bolts can be fired at least once every two seconds, so a turbolaser cannon must have a sustained firepower of at least 15 terawatts. Assuming they can be fired once per second, they would have a sustained output of at least 30 terawatts (since one of the smallest estimated diameters of the asteroids is used, and only the melting point, this estimate is ridiculously conservative).
In comparison, the United States now produces 500-600 gigawatts of electrical power. This is a whole order of magnitude less than the power of a single middle-sized turbolaser.
The atomic bomb that was dropped on Hiroshima was rated at 15 kilotons. This translates to about 63 terajoules. Using my conservative estimate for TL bolts (ignoring vaporisation), a middle-sized TL bolt has about 30 TJ of energy.
Therefore, a TL bolt has about half the energy of the Hiroshima bomb."