That doesn’t seem to be true anymore, even when excluding the externalities of CO2 and NOx generation or groundwater pollution. The life-cycle costs of wind and solar electricity production keep dropping and, according to some studies, are already lower than the costs for coal and gas plants. And when you include the externalities, the cost of renewables is less than half of the cost of fossil-fuel burning generation.
Even the current administration cannot hide this fact in their 2019 Annual Energy Outlook report:
These do not include externalities and notice how they are not even showing conventional coal and nuclear, they are not competitive anymore.
