Solutions Drains, as energy has 4 entries with similar clues

• 3-letter words
• ergEnergy unit hidden in "energy"
• 6-letter words
• sewageWaste material carried away in drains
• 7-letter words
• staminaProduces cartoons without energy, needing upturn in sustained energy
• 8-letter words
• plugholeA hole at the lowest point of a bath or sink through which the water drains away