Ahem, let's see here: Alpha Wires II, that's 2.6 essence loss. Mage takes Geasa: Talisman, Gestures, and Somatic. That guarantees that providing that the Mage uses those three things he operates at optimum level, as well as casting at least 2 spells per combat turn. Without those, the mage can still dump all his/her dice into a low force power-bolt and still wallop most people without a care.
Alternately, you could go with reaction enhancers to pump up their reaction on the cheap (essence wise) or they could go bioware and get a synaptic accelerator rating 2, and still not take ANY magic loss (according to 3rd edition errata, a magician doesn't face magic loss from bioware until their bio index is 2) Then again, if synaptic accelerators are cultured, you can't get them at chargen anyway.
I wonder if it's possible for a mage to detonate explosives with a radio signal spell?