Kristina Bergman1,, Ji Li2, Jean-Baptiste Thomas1, Yonghui Gao2 and Fredrik Gröndahl1
1 KTH Royal Institute of Technology, Department of Sustainable Development, Environmental Science and Engineering Teknikringen 10B, SE-100 44 Stockholm, Sweden
2 School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, China
The environmental performance of cultivated seaweed has gained large interest. The low material, energy and water requirements together with nutrient uptake suggests seaweed can be a promising alternative source of food, fuel and biomaterials to mitigate environmental impacts. So far, the evaluations of environmental performance of seaweed are mostly based on European cultivations at research and pilot scale. This although Asia stands for 97 % of global seaweed production with China alone producing 58 %. In this study, we calculate and compare the environmental footprint of nine kelp production systems described in literature and include a Chinese farm at industrial scale that has not previously been described. We extracted inventory data from all studies and recalculated environmental impacts using Life Cycle Assessment (LCA), applying the same background data and method choices with the aim to compare effects of scale and cultivation system. The yearly harvest of the Chinese farm was 1000-4000 times larger than the farms previously evaluated with LCA. Preliminary results suggest that streamlined and mature production in the large-scale Chinese kelp farm led to lower electricity and fuel consumption compared to small-scale production. Thus, placing the Chinese farm on the lower end when comparing the carbon footprint. There was a large variation in carbon footprint per kg kelp, which implies that the kelp cultivation sector has a large room for optimisation. Evaluating large-scale cultivations allows for better evaluations of climate change mitigation potential as well as gives insight on both effective cultivation practises and the limits for optimisation.