It depends of course on what kind of analysis you are performing. Let's take the off-taker's perspective an industrial consumers, we will calculate the LCOE of the Captive PV system: this means that per kWh, the levelized costs throughout the life-time of the system (considering all costs associated) - we are translating project that is very capiial intensive in the first years and relatively with low O&M costs to monetary terms, comparing this against electricity tariffs. As seen from the graph shown earlier in our presentation, we are able to compare the LCOE of the captive system which is estimated with high probability for 25 years against a tariff that we know that the off-taker are based on. From that we will know the feasibility of the project, that is if the LCOE is below the tariff. However, it should be noted that the electricity tariff is uncertain in the future- Also the captive users might hedge against this increase. The LCOE is a nice metric that allows you to compare; but you could also consider other viable metrics (e.g. expected future evolution of the tariff).