Offshore wind energy development has been driven by government support schemes; however, recent cost reductions raise the prospect of offshore wind power becoming cheaper than conventional power generation. Many countries use auctions to provide financial support; however, differences in auction design make their results difficult to compare. Here, we harmonize the auction results from five countries based on their design features, showing that offshore wind power generation can be considered commercially competitive in mature markets. Between 2015 and 2019, the price paid for power from offshore wind farms across northern Europe fell by 11.9 ± 1.6% per year. The bids received in 2019 translate to an average price of €51 ± 3 MWh⁻¹, and substantially different auction designs have received comparably low bids. The level of subsidy implied by the auction results depends on future power prices; however, projects in Germany and the Netherlands are already subsidy-free, and it appears likely that in 2019 the United Kingdom will have auctioned the world’s first negative-subsidy offshore wind farm.

离岸风能发展受到政府支持计划的推动；然而，最近的成本降低提高了海上风力发电比传统发电便宜的前景。许多国家使用拍卖来提供财务支持；但是，拍卖设计上的差异使其结果难以比较。在这里，我们根据五个国家的设计特点协调了拍卖结果，表明海上风力发电在成熟市场中可以被认为具有商业竞争力。在2015年至2019年之间，北欧海上风电场的电力支付价格每年下降11.9±1.6％。2019年收到的投标平均价格为€51±3 MWh ^-1，而且实质上不同的拍卖设计收到的出价也相对较低。拍卖结果暗示的补贴水平取决于未来的电价；然而，德国和荷兰的项目已经无补贴，而且看来英国可能会在2019年拍卖世界上第一个负补贴的海上风电场。