The potential for significant increases in VAWT farm performance compared to isolated turbines is well documented and could potentially allow VAWTs to compete in the Wind Energy market. In order to determine the most effective layout based upon both average turbine efficiency and efficient use of area, different configurations which have been shown to offer improved performance such as the 'School of Fish' design alongside new derivative and hybrid designs are compared and optimised using 2D URANS (Unsteady Reynold's Averaged Navier Stokes) CFD simulations. The results show that on a farm scale, the optimised staggered configuration provides the highest array power coefficient for a single wind direction, with a farm design proposed in order to achieve maximum efficiency and results showing increases in array power of up to 80%. Fluid flow mechanisms which cause this improvement are also identified. (C) 2019 Elsevier Ltd. All rights reserved.