Successful development of Wave Energy Conversion technology is made difficult by a combination of factors, these include; the inaccessible nature of the target ocean locations; the relatively high cost of fullscale device testing; the stochastic nature of ocean waves; the strong interaction between subsystem designs; and, the apparent gulf between required and, so far, demonstrated performance. These difficulties taken together mean that design optimisation in software should assume a greater importance in wave energy than it does in other industries at comparable maturity. This paper presents a techno-economic optimisation of a generic wave energy converter, namely a hinged barge. The optimisation is techno-economic in the sense that the optimisation algorithm manipulates the technical parameters of the device in order to improve the value of an economic objective function. The economic objective function used is the estimated net present value of a large array deployment. The technical parameters included are device geometry, power transmission equipment design and control parameters. A comparison between the techno-economic optimisation and an optimisation using a purely technical objective function is presented. The results show that the techno-economic optimisation results in a superior economic performance and significantly different optimised designs.