Few ideas how to make Vodyani Essence gain more interactive and consistant, without depending on RNG start. One, two or more of those can be implemented at the same time into the game.
1. Essence from Scrap Module granted via learning first tech in military tree. Completing certain quest, in Vodyani quest line, would reward with a better version of that module or it could be researched like other essence gaining module.
2. Battle Tactic that allows to gain Essence per destroyed and lost ship at the same time.
3. Faction passive/trait. Just like our friends Hissho gains keii, we gain Essence by winning space battle (ground battle do give essence, that system becomes hunting ground).
4. Complete new module, that works almost similiar to those that kill crew of ship. Instead of destroying crew it would convert it to essence.