It is important to recognize the limitations of the LUEC metric as well as its strengths. Arguably there are two key limitation of LUEC. The first is that the LUEC measure is designed to capture costs at the plant-level rather than the system- or grid-level. For example, the classic LUEC measure does not typically incorporate system-wide implications of choosing a particular technology (such as reserve requirements). Insofar as the LUEC measure is employed to compare alternatives within a particular class of technologies this may not be a major handicap, since technologies within such a class may have similar system-wide implications and associated costs (although differences in the capacity of different plants within a given class may be expected to lead to different system-wide implications). A more general evaluation approach would seek to explore the system-wide implications of a particular vendor’s offer by exploring the systemic implications of embedding the associated technology within a grid; such an exploration could in principle be undertaken using an energy planning model. The second key limitation of LUEC is that it assumes – at least implicitly – that inputs to the LUEC calculation are ‘correctly’ priced, in that they capture all of the societal costs which will arise from the operation of a particular technology. This limitation is perhaps best illustrated by considering the health costs imposed on society by pollution from a particular technology. Typically these costs are not included in the LUEC calculation (not least because they are difficult – though not impossible – to express in the monetary terms which make up the numerator of the LUEC metric). Effectively these costs are ‘priced’ at 0. As a result, a simple LUEC comparison between two technologies will fail to fully reflect their respective societal worth; a technology which is less polluting (i.e. which offers public health benefits) will be unfairly disadvantaged if the technologies are valued using the simple, classic, LUEC metric. If societal costs such as these can be ‘monetized’ (i.e. given a monetary value) then it may be possible – in principle – to include them in the LUEC measure.