Unique algal lipids known as alkenones were evaluated as potential phase change materials (PCMs). Alkenones were isolated and purified from commercial Isochrysis algal biomass and their thermal properties evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Alkenone crystallinity appears to impact latent heat of fusion (Delta H-fus), however both the Delta H-fus and melting temperature (similar to 65 degrees C) of two different alkenone compositions obtained from separate commercial Isochrysis suppliers were nearly identical. Compared to a synthetic his-fatty acid PCM, alkenones showed improved thermal stability by TGA and comparable Delta H-fus (up to 275 J/g) by DSC. Overall the results demonstrate competitive properties for alkenones to other renewable and non-renewable PCMs such that alkenones represent a promising and potentially superior alternative for various 'green' PCM technologies. (C) 2018 Elsevier Ltd. All rights reserved.