Energy efficiency comparison of intermittent and continuous drying of seaweed as a novel biomass

Seaweed is an abundant and rapidly renewable marine biomass, yet its high moisture content necessitates energy-intensive drying prior to utilization. Although intermittent drying (ID) is frequently claimed to be more energy-efficient than continuous drying (CD), most studies rely on unequal total drying times, making the reported energy savings inconclusive. This study provides the first fair comparison (allocating the same total drying time for both methods) between ID and CD for Bladderwrack (Fucus vesiculosus). In the first case, two ID methods and one CD method were evaluated experimentally under identical energy input and total duration (180 min). Results show that ID provides no significant improvement in moisture reduction (p > 0.05) or specific energy consumption (Ē ratios = 0.96–0.98) compared with CD under fair conditions. In the second case, when ID was allowed a longer total drying time while maintaining equal energy consumption, moisture removal increased by approximately 8 % (Ē ratios ≈ 1.2). Additionally, ID resulted in 5–10 °C lower maximum temperatures, suggesting potential quality-preservation benefits. A broader analysis of previous studies suggests that reported efficiency gains for ID are frequently attributable to longer drying times rather than intrinsic process efficiency. These findings highlight the context-dependent nature of ID’s benefits and underscore the importance of standardized comparisons when assessing drying methods for sustainable biomasses.