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Energy budgets were developed for greenlip abalone (Haliotis laevigata) under different feeding scenarios to predict growth, metabolic and waste outputs. The energy budgets of abalone fed live macroalgae (Ulva sp. or Gracilaria cliftonii) and an equal mix of those two macroalgae species with and without nutrient enrichment, or one of three control formulated commercial diets, at 22°C for 93 days were investigated. Among non-enriched algal treatments, abalone fed G. cliftonii and mixed diet treatments had significantly higher ingested feed energy and absorbed energy than those fed Ulva sp. Abalone fed non-enriched G. cliftonii invested significantly more energy into somatic growth than those fed Ulva sp. and the mixed diet treatment. For diets with nutrient enrichment, ingested feed energy and absorbed energy rate of abalone fed G. cliftonii and mixed diet treatments were significantly higher than those fed Ulva sp. Nutrient enrichment increased crude protein in live macroalgae, and ammonia excretion energy rate was higher for abalone fed enriched macroalgae compared to non-enriched. Abalone fed the control commercial diets spent more energy in all components compared to those fed the live macroalgae treatments. The major component of the energy budgets in abalone fed the commercial diets and live macroalgae diets was somatic growth energy, ranging from 25.5% to 37.7% of ingested feed energy, except for abalone fed live Ulva sp. where the major component was respiration energy (38.5%). Overall, abalone fed the formulated diets or live non-enriched G. cliftonii could increase ingested feed energy, absorbed energy and somatic growth energy.