Economic Viability and Environmental Assessment of Marine Renewable Energy Technologies: A Comparative Framework for Tidal Stream Energy and Offshore Wind Power in the United States

This study examines the comparative economics and social benefits of tidal stream energy (TSE) and offshore wind farms in the United States, adapting the methodology from Lamy & Azevedo’s 2018 United Kingdom analysis. Using levelized cost of energy (LCOE) projections, market data analysis, and social benefit quantification, we evaluate whether TSE projects offer sufficient value to justify their higher costs relative to offshore wind. Our analysis reveals that TSE projects provide approximately $12/MWh more in net social benefits than offshore wind for standard 200 MW projects, increasing to $42/MWh for smaller 20 MW projects. These benefits derive from higher energy value correlation with peak demand periods, superior generation predictability that eliminates forecast error costs, and the absence of visual landscape impacts. However, despite this social benefit premium, TSE projects remain significantly more expensive, with current LCOE estimates of $450/MWh compared to $125/MWh for offshore wind—a gap of $325/MWh. Cost projections through 2050 indicate this difference will narrow to approximately $90/MWh but remain substantial. Under base case assumptions, standard TSE projects are unlikely to become cost-competitive until approximately 2085, while small projects could achieve competitiveness around 2065. Under optimistic cost reduction scenarios, competitiveness might be achieved by 2070. These findings suggest that while TSE offers meaningful social benefits, continued research and development investment is warranted primarily for niche applications such as island communities, visually sensitive coastal areas, and hybrid renewable energy systems where predictable generation complements variable wind and solar resources.