Techno-economic assessment of floating offshore wind in California

Abstract California legislation has set ambitious goals of reaching 2–5 gigawatts of floating offshore wind (FOSW) by 2030, and 25 GW by 2045. FOSW remains an emerging technology with significant uncertainty surrounding its future development. We estimate the electricity output, levelized cost of energy (LCOE) and levelized cost of transmission (LCOT) for two locations in California where offshore wind projects are currently planned (Humboldt and Morro Bay). We use data collected in a prior extensive expert elicitation, complemented by publicly available data. Assuming a 30 year lifetime and a 5.69% discount rate for the offshore components, and a 60 year lifetime and 4.40% discount rate for onshore transmission infrastructure, and under the ranges of input values provided by the experts, we find that the 2035 median levelized costs of energy and transmission (LCOE + LCOT) range from $95 to $121 per MWh. Operation and maintenance costs, turbines, and floating foundations are the largest contributors to levelized costs. In addition to a base-case analysis, we perform single-parameter sensitivity analyses and show that the results are highly sensitive to discount rate, lifetime, and farm power density. To further understand the overall uncertainty, we perform a Monte Carlo simulation assuming uniform distributions for each component-cost, finding combined LCOE + LCOT ranging from $95 to $200 per MWh. For all scenarios, transmission represents a small portion of total project costs. This analysis emphasizes the importance of strategic planning and investment in FOSW to meet California’s renewable energy goals.