Our study uses algae oil to supply remaining demands in oil routes after the use of residues, waste and bioenergy crops. Because commercial scale algae growing and harvesting is currently still in development, we only include significant algae use from 2030 onwards. The approach to using algae in our work is based on a recent Ecofys study [30] on the worldwide potential of aquatic biomass. This study identified a number of different long-term feasible potentials for aquatic biomass. The most conservative scenario only contains algae oil from microalgae grown in open ponds on non-arable land filled with salt water. The total potential for algae oil from this technology was estimated at 90 EJ of oil. We envisage an algae cultivation system where the non-oil algae biomass are used to provide a nutrient loop where possible and the required energy for the cultivation and processing of the algae.

The maximum amount of algae oil actually used in the demand side scenario [1] is 21 EJ of oil in 2050. Based on the yields calculated in the Ecofys study, this amounts to approximately 300,000 km2 (30 million hect­ares) use of non-arable land. The 21 EJ oil use is about 25% of the 90 EJ algae oil potential identified in the most conservative scenario containing only algae oil from microalgae grown in open ponds on non-arable land filled with salt water. Therefore, the algae oil use in the demand side sce­nario fits comfortably within the potential identified in the Ecofys study, especially as further potential from algae cultivation in open water may be tapped due to future technological progress.