Energy use
Energy use in algae production varies greatly between microalgae (Spirulina, Chlorella) and macroalgae (sugar kelp), and depending on the production method (i.e. in open ponds or in bioreactors).
Electricity is required at all microalgae production stages: cultivation, water treatment, harvest, washing, pasteurisation, and packaging.
For macroalgae, energy is used to power boats for accessing cultivation sites and mostly to operate drying and freezing equipment after harvest.[1] The evidence suggests that the energy use of sugar kelp production is higher to much higher than in soy protein production.[2]
Spirulina production in open ponds has been found to be lower than that required to produce beef,[3] but it may be higher with other production methods.[4]
While drying and freezing make up a significant share of the energy used, anaerobic fermentation provides a much less energy intensive alternative for conservation. However, reliable fermentation protocols for the commercial production of cultivated macroalgae are not yet established.
[1] Koesling M et al., ‘Environmental impacts of protein-production from farmed seaweed: Comparison of possible scenarios in Norway’, Journal of Cleaner Production, 307: 127301, 2021; Thomas J-BE, Sodré Ribeiro M, Potting J, Cervin G, Nylund GM, Olsson J, Albers E, Undeland I, Pavia H, Gröndahl F, ‘A comparative environmental life cycle assessment of hatchery, cultivation, and preservation of the kelp Saccharina latissima.’ 78 (1):451-467, 2020. doi:10.1093/icesjms/fsaa112.
[2] Koesling M et al., ‘Environmental impacts of protein-production from farmed seaweed: Comparison of possible scenarios in Norway’, Journal of Cleaner Production, 307: 127301, 2021; Philis G, Gracey EO, Gansel LC, Fet AM, Rebours C, ‘Comparing the primary energy and phosphorus consumption of soybean and seaweed-based aquafeed proteins – A material and substance flow analysis.’ J Clean Prod 200:1142-1153, 2018, .
[3] Tuomisto HL, Texeira de Mattos MJ, ’Environmental impacts of cultured meat production’, Environ Sci Technol., 2011, Jul 15, 45(14):6117-23, doi: 10.1021/es200130u.
[4] Smetana S et al. 2023.