A theoretical upper limit for offshore wind energy extraction

<h2>Summary</h2> Future energy systems need offshore wind. However, large-scale deployment faces aerodynamic limits that constrain efficiency, energy yield, and grid integration. We present a closed-form analytical model for the theoretical upper limit to offshore wind farm production, expressed through a dimensionless Wind Farm Wind Factor. The model and limit are validated against data from 72 offshore wind farms over 420 cumulative years, demonstrating strong agreement including operational losses. We benchmark national policy targets in Europe and the US, revealing large overestimations of energy production—by nearly 50% in one case—underestimating energy costs, power variability and integration costs, curtailment, and policy risks. The model clarifies the critical design trade-offs between turbine height, specific power, and wind farm density. Our model provides a rigorous yet simple framework, readily usable by engineers, planners, and policymakers to forecast wind farm performance, support system planning, and to set realistic targets consistent with aerodynamic limits.