|Adventures of an EVE Online Newb||
When doing a level 2 mission today, I discovered an enemy ship using an energy neutralizer on me. It sapped away my capacitors and left me dead in space. I wasn't able to fire any of my weapons, use my shields, and I even had a difficult time warping out of there. I tried the mission a few more times but the same ship kept hitting me with that energy neutralizer!
Attacking an Enemy's Capacitor
There are two types of ship equipment you can use to sap away an enemy's energy; Energy Destabilizers and Energy Vampires. Destabilizers neutralize a portion of the target ship's capacitor, while vampires drain energy from the target ship and add it to your own. The reason that players prefer destabilizers is because vampires are limited to draining energy until it reaches your own capacitor amount.
The skills needed for energy destabilizers and energy vampires are:
Increasing Your Own Capacitor
To protect yourself against sapping and against your own stupid fittings (having shield boosters is awesome but not when they sap you down to zero energy!), you can use some ship equipment to increase the capacitor energy of your ship. There are rigs and other upgrades that can be bought and fitted that will reduce how much energy is used by your equipment or will increase the total amount of energy available but I haven't looked into them yet.
The following ship equipment is available for increasing your own capacitor: