The performance of a wind turbine within an array is not necessarily equivalent to the performance of a free-standing turbine because the presence of the neighboring turbines influences the incoming flow. However, insight into these blockage effects is still lacking. Here, we use large eddy simulations to investigate how the blockage effect depends on the turbine thrust coefficient CT . We consider three main scenarios: a free-standing turbine, a closely-spaced spanwise-infinite row of turbines, and an entire wind farm with a high turbine density. We observe that the power production of turbines in the row increases approximately linearly with CT′ when compared to the production of a free-standing turbine. Here, where a is the induction factor. In contrast, the power output of turbines in the first row of a wind farm decreases approximately linearly with CT when compared to the production of turbines in a corresponding, solitary row.