59 the ocean. Once at the bottom, the carbon sequestered will not enter the atmosphere for 1000 years, which is considered “permanent” sequestration (Running Tide, 2021b). This means that the carbon offset is additional or is a carbon capture that would not have happened otherwise. Pilot projects have demonstrated the efficacy of using seaweed to capture carbon. One Korean project, the Coastal CO2 Removal Belt, has proven its pilot farm can capture roughly 4 tons of CO2 per acre per year (Chung et al., 2013). Stripe, an online payment processing company, has invested $8M in carbon capture projects, including a project proposed by Maine-based Running Tide. Stripe is investing in carbon capture projects to help build a carbon capture market and presumably for some good press. Stripe agreed to pay Running Tide $150,000 to capture 600 metric tons of CO2 ($250/ton CO2) and an additional $350,000 to invest in research and development for Running Tide’s 100 microfarms in an effort to increase the carbon capture of the farms (Running Tide, 2021a). There are challenges of using kelp as a carbon sink. Prices of kelp may be driven down as kelp production increases overall, which in turn may discourage new entrants into the market. Nutrient availability, shifting temperatures, and storms may impede the growth of kelp along the coasts; however, for colder areas, kelp yield may increase due to rising temperatures in the Arctic. Another limitation for using kelp as a carbon sink is the cost of growing kelp compared to the value of capturing one ton of carbon. Running Tide claims to be close to capturing CO2 for $375/ton and predicts that commercial deployment would cost them $150/ ton of CO2 (Running Tide, 2021b). The cost of growing kelp for carbon capture would vary greatly on the factors of production for individual farms. However, because the kelp does not need to be harvested or processed, the costs to grow it would be much lower than for commercial harvesting. Running Tide estimates that sugar kelp sequesters 0.001 tons of CO2 per kg of kelp by dry weight, although the kelp used is not harvested or dried (Running Tide, 2021b). Using this information, Running Tide’s estimated commercial deployment costs per ton of CO2 and the potential revenues by selling carbon credits are summarized in Table 4, assuming the same farm layout as discussed previously. Using Kelp for Environmental Services Kelp farms offer many benefits to Alaska’s coastal habitats. Wild or farmed kelp can reduce ocean acidification and its effects, add oxygen to the environment to mitigate ocean dead zones, and offer habitats for marine animals. The Artic is the ocean most vulnerable to acidification. Ocean acidification occurs when CO2 released into the atmosphere dissolves in the ocean and decreases the pH of the water. This is more likely to happen in waters with lower temperatures, which puts Alaska’s waters at risk (Krause-Jensen et al., 2015). The pH of Earth’s oceans has decreased by 0.1 since the beginning of the Industrial Revolution and is on a path to decrease further. This acidification can be harmful to marine animals, especially those Table 4 Carbon Capture Costs 10 Lines/Acre 5 Lines/Acre 20 Lines/Acre Wet pound yield 1,200,000 600,000 2,400,000 Carbon per yield (tons) 82 41 163 Total cost $12,247 $6,124 $24,494 Revenue $20,412 $10,206 $40,823 Profit $8165 $4082 $16,329 Source: Author’s calculations.
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