Biogas from Macroalgae: is it time to revisit the idea?

Adam D Hughes,Kenneth D Black,Maeve S Kelly,Michele S Stanley

doi:10.1186/1754-6834-5-86

Adam D Hughes, Kenneth D Black + Show 2 more

Open Access

https://doi.org/10.1186/1754-6834-5-86

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Abstract

The economic and environmental viability of dedicated terrestrial energy crops is in doubt. The production of large scale biomass (macroalgae) for biofuels in the marine environment was first tested in the late 1960’s. The culture attempts failed due to the engineering challenges of farming offshore. However the energy conversion via anaerobic digestion was successful as the biochemical composition of macroalgae makes it an ideal feedstock. The technology for the mass production of macroalgae has developed principally in China and Asia over the last 50 years to such a degree that it is now the single largest product of aquaculture. There has also been significant technology transfer and macroalgal cultivation is now well tried and tested in Europe and America. The inherent advantage of production of biofuel feedstock in the marine environment is that it does not compete with food production for land or fresh water. Here we revisit the idea of the large scale cultivation of macroalgae at sea for subsequent anaerobic digestion to produce biogas as a source of renewable energy, using a European case study as an example.

Highlights

Growing terrestrial crops for biofuel may make a negligible contribution to net greenhouse gas emissions [1,2] and may cause other environmental impacts while reducing freshwater resources and food security [3]
Given these limitations there has been renewed / increased interest in aquatic and marine production for biofuels [4,5]. This interest can be divided into two principal components: biofuels derived from macroalgae and biofuels derived from microalgae
Nutrients taken up by macroalgal culture, on the scale required for biofuel production, would be far less than that produced by agricultural, urban sources and fin-fish aquaculture

Summary

Introduction

Growing terrestrial crops for biofuel may make a negligible contribution to net greenhouse gas emissions [1,2] and may cause other environmental impacts while reducing freshwater resources and food security [3]. Inshore areas are already under significant pressure so the culture of macroalgae at the scale required for biofuel production must be largely located on continental shelves.

Results

Conclusion