Hydrokinetic energy development: Considerations of cumulative impacts to aquatic resources

Commercial development of hydrokinetic energy technologies for energy production will add to existing environmental stresses and cumulative effects in freshwater and marine ecosystems. In rivers, the effects of hydrokinetic energy development would occur in the context of impacts associated with other activities such as commercial and recreational water use, water withdrawals, and discharges. In marine environments, hydrokinetic energy developments must compete with aquaculture, other offshore energy development, defense-related activities, mining, commercial shipping, recreational and commercial fishing, and recreational boating and beach use. As with cumulative effects associated with other anthropogenic activities, the contribution of future hydrokinetic energy developments to overall impacts on aquatic resources could be additive, synergistic, or offsetting. To fully understand potential cumulative impacts of commercial level hydrokinetic energy development, impacts must be evaluated by considering both (1) the current level of impacts from other anthropogenic stressors and (2) the incremental increases in impacts from the deployment of multiple hydrokinetic energy generation units at specific locations. To begin evaluating the cumulative impacts of commercial-level developments, a framework has been developed employing conceptual impact models that tie together hydrokinetic energy development with other anthropogenic activities, considering impacts not only of single-unit deployments but also large-scale commercial developments.