Scenario-based cost-effectiveness analysis of ballast water treatment strategies.
This work evaluates technological strategies that include conventional vessel-based and alternative barge-based technologies to meet various treatment standards and combinations. We construct a vessel-versus-barge compliance cost framework informed by California efforts to provide additional protection from ballast discharge invasive risk. The technology-policy goal is to achieve the regulatory standards with appropriate technology, and meanwhile, minimize the compliance cost to reduce the burden on the shipping industry. The results show that the required numeric standards matter a lot. If a single global standard is a weak standard, then adopting vessel-based compliant technology is less costly than centralized barge-based compliance. We consider these findings to apply generally beyond the California context. Specifically, if some region or all regions adopt standards different from current global standards (i.e., stricter), barge-based systems can be less costly than retrofitting world fleets. The findings reveal the potential role of barge-based treatment measure. The increased $0.7 billion compliance cost for the U.S. to achieve stricter ballast water regulation per year may inform the relevant policymakers.