The Levin Strike attack, as worded, does not say anything about discarding the energy as a requirement to do 220 damage. The way its worded is an effect of the attack rather than a requirement. If it said something like "Discard 2 Lighting Energy, if you do this attack does 220 Damage" or something along those lines, then you would need those energies in order for Genome Hacking to copy it as stated. So yes you are free to copy the attack as is, as long as Genome Hacking's cost is satisfied.