Financial viability of energy from marine biomass: re-examination of the evidence

Macroalgae has been suggested as a source of next generation bioenergy. For this to materialise commercial viability or social benefits have to be demonstrated. At least any expected financial loss has to be modest enough to be offset by potential wider social impacts. This paper summarises and re-examines evidence on potential financial viability concentrating on the anaerobic digestion (AD) of harvested seaweed. We estimate the energy potential of such operations in Scotland and conduct sensitivity analyses around financial parameters, feedstock costs and energy prices. The outcome is highly sensitive to the input price of the feedstock. The analysis suggests a significant increase in wholesale prices of energy would be needed to ensure commercial viability. However, we do not consider potential synergies with other AD operations or local industries. Nor do we allow for social costs and benefits as would be included in a full cost-benefit framework.