This paper assesses the economic benefits of DG and how incentive schemes and technical constraints can affect those benefits. DG can possibly reduce network power flows and losses and some DG can have carbon saving benefits, on the other hand DG can sometimes breach technical limits and therefore need to be constrained. The technical limitations such as line loss, voltage, line flow, fault limits of the distribution network into which it will be incorporated are taken into account. A previous techno-economic assessment methodology has been extended to include the influence of load duration curves on duration and costs of constraints. Geographic distribution of load with respect to the DG and the existing bulk supply point strongly influence the impact of constraints and these have been explored through case studies using biomass power plant and sections of the UK network. The several revenue support mechanisms available for a DG developer and to an operator in the UK are explored in detail. In the context of incentivising the increased DG penetration in distribution networks it is of prime importance to assess its impact on network operation. The presented analysis forms the basis for an effective planning tool that combined technical and economical aspects into a single framework.