It shows that indirect carbon emissions of all technologies are at least an order of magnitude lower than the direct emissions from fossil fuel combustion. It includes the warming of rivers and lakes due to the cooling requirements of large thermal power plants, in particular nuclear plants, as well as the landscape impacts of renewables with large requirements in terms of land use such as wind, solar and hydro.15 In case of biomass-firing, it is important that woodlands are forested sustainably. The European project on the Cost Assessment for Sustainable Energy Systems (CASES) draws together much of the available information on the external effect of power generation in monetised form. While here is not the place to discuss the merits, limits and proper utilisation of the monetisation of external effects, such synthetic estimates if carefully prepared provide a good qualitative indicator of the areas in which policy action might be needed.