Energy performance and greenhouse gas emissions of kelp cultivation for biogas and fertilizer recovery in Sweden
2016 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 573, 347-355 p.Article in journal (Refereed) Published
The cultivation of seaweed as a feedstock for third generation biofuels is gathering interest in Europe, however, many questions remain unanswered in practise, notably regarding scales of operation, energy returns on investment (EROI) and greenhouse gas (GHG) emissions, all of which are crucial to determine commercial viability. This study performed an energy and GHG emissions analysis, using EROI and GHG savings potential respectively, as indicators of commercial viability for two systems: the Swedish Seafarm project's seaweed cultivation (0.5 ha), biogas and fertilizer biorefinery, and an estimation of the same system scaled up and adjusted to a cultivation of 10 ha. Based on a conservative estimate of biogas yield, neither the 0.5 ha case nor the up-scaled 10 ha estimates met the (commercial viability) target EROI of 3, nor the European Union Renewable Energy Directive GHG savings target of 60% for biofuels, however the potential for commercial viability was substantially improved by scaling up operations: GHG emissions and energy demand, per unit of biogas, was almost halved by scaling operations up by a factor of twenty, thereby approaching the EROI and GHG savings targets set, under beneficial biogas production conditions. Further analysis identified processes whose optimisations would have a large impact on energy use and emissions (such as anaerobic digestion) as well as others embodying potential for further economies of scale (such as harvesting), both of which would be of interest for future developments of kelp to biogas and fertilizer biorefineries.
Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 573, 347-355 p.
Biorefinery, Economy of scale, Energy return on investment (EROI), EURED GHG savings, Saccharina latissima, Swedish macroalgae cultivation, Anaerobic digestion, Biofuels, Biogas, Economics, Fertilizers, Gas emissions, Investments, Refining, Seaweed, Biorefineries, Energy return on investments, Macro-algae, Greenhouse gases
IdentifiersURN: urn:nbn:se:kth:diva-195182DOI: 10.1016/j.scitotenv.2016.07.220ISI: 000390033600013ScopusID: 2-s2.0-84983638479OAI: oai:DiVA.org:kth-195182DiVA: diva2:1047743
FunderSwedish Research Council, 2013-11209-24630-54
QC 201611182016-11-182016-11-022017-01-16Bibliographically approved