Although early experiences indicate that the maturity of deployed technology might not be sufficient for operating wind farms in large scale far away from shore, the rapid development of offshore wind energy is in full progress. Driven by the demand of customers and the pressure to keep pace with competitors, offshore wind turbine manufacturers continuously develop larger wind turbines instead of improving the present ones which would ensure reliability in harsh offshore environment. Pursuing the logic of larger turbines generating higher energy yield and therefore achieving higher efficiency, this trend is also supported by governmental subsidies under the expectation to bring down the cost of electricity from offshore wind. The aim of this article is to demonstrate that primarily due to the limited wind resource upscaling offshore wind turbines beyond the size of 10 MW (megawatt) is not reasonable. Applying the planning methodology of an offshore wind project developer to a case study wind farm in the German North Sea and assessing energy yield, lifetime project profitability and levelized cost of electricity substantiate this thesis. This is highly interesting for all stakeholders in the offshore wind industry and questions current subsidy policies supporting projects for developing turbines up to 20 MW. (C) 2014 Elsevier Ltd. All rights reserved.