policymakers and decisionmakers would be welladvised to take note of the scale of the disruptions ahead it should be pointed out that the shares of variable renewables that are underlying the present analysis are considerably below the ambitious longterm objectives that a number of oecd countries have set themselves in this respect this section reports the origin of the data used in the study as well as the assumptions and methods of calculation used a real discount rate of has been assumed to compute fixed and variable costs when not present in the projected costs database data for a specific power plant type have been replaced by other data available in the projected costs study for instance data for coal and gasfired power plants for france are derived from those from germany