B.6 The pipeline information for electricity generation is particularly uncertain. National Grid data are included on projects that have agreements to connect to the grid in place. Market intelligence suggests that up to 50 per cent of these projects will not be taken forward, for example because the demand for power does not warrant the particular project being built or the economics of a particular project are not favourable or there are problems with obtaining planning consents. Cost estimates are therefore provided as HM Treasury estimates by fuel type that allow for the expected proportion of projects that should proceed. These use the National Grid TEC data combined with estimated capital costs per unit of output for a generic plant, high level construction time estimates and estimates drawn from market intelligence on the proportion of projects that will proceed.
B.7 Project timings represent the earliest possible date for connection to the grid. In reality investment is likely to take place over a longer timeframe, reflecting the complexity of major infrastructure projects, market demand and developer's commercial considerations.
B.8 These estimates are indicative and designed to provide a sense of the potential scale of investment. The Government's statement of the investment that is needed in terms of generating capacity is set out in the energy National Policy Statements that inform the major infrastructure planning system