It seems that the effects of this policy is a bit offset, because you can have the slider at subsidize and ecologist still like you, and you can have it at widespread expansion and it still reduce your GDP and doesn’t decrease oil demand.
I don’t know how it is coded, but it seems to me that it is calculating the effects based on the fraction actual cost vs max cost instead of the position of the slider.
Also at hight leves it should reduce CO2 emissions because it’s CO2 emissions are almost the same as wind power and less than every other energy source, based on IPCC 2014.