Certain repeating game actions require a payment in $OIL, for example using Charging Stations to replenish you Robots' Stamina. As an alternative to paying with $OIL, players can stake and lock their $OIL to receive $ENERGY that can be used as an alternative payment method.
$ENERGY is a special non-transferable token that serves to support Stake-to-Play mechanic. Staked and locked $OIL allows players to generate $ENERGY and use it instead of $OIL for game actions.
$ENERGY replenishes over time, and has a Max Capacity. Replenishment rate and Max Capacity depends on the amount of $OIL staked.