The schemes to remunerate investments should be oriented at favouring the transition towards a sustainable energy supply system.
An obvious, though often neglected truth is that an unsustainable energy supply system cannot be sustained indefinitely. Sooner or later, we will be forced to change and it is wise to manage the transition over time with this in mind.
However, renewable energy deployment has an impact on nature and society, and it is important to try to keep this to a minimum by taking into account all kinds of effects (local/ global, on air, ground and soil, on biodiversity and social structures etc.). Thus, one should not only consider the electricity generation process, but the whole lifecycle, including the extraction, transport and refinement of fossil, nuclear and biomass fuels, as well as the whole manufacturing process for all kinds of facilities, decommissioning and waste disposal. Those renewables with the lowest GHG lifecycle balance and lowest other impacts should be privileged.
The reference to a sustainable “energy supply system” points to the interactions between the electricity sector and other parts of the European and global energy supply systems. Renewable electricity is needed to substitute for fossil fuel consumption in the heating and transport sectors as well as in power generation, which provides even stronger reasons to support continued progress in RES generation in the coming decades.