A great deal of energy can potentially be generated using underwater tidal current turbines. These operate in the same manner as conventional wind turbines, and given that seawater is roughly 800 times denser than air can harvest more energy. Moreover, one major advantage of tidal current energy over other forms of renewable energy is that underwater currents and tides are predictable and the energy generated can be calculated in advance. Due to the difficulties faced in operating in the open ocean, the loads the turbine blades would be subjected to and the need for fundamental research into the behaviour of composites in seawater, tidal current energy is still at the prototype stage. This is starting to change with several prototype turbines operating for extended periods in the open ocean. In this work, the costs associated with creating turbine blades is investigated. Although tidal energy is at the prototype stage it is now possible to start to model the costs of producing the blades or the turbine. The resulting models can help reduce cost and hence make tidal current turbines commercially viable.