I agree... but it all depend on the situation. For example, existing power grid, including conventional power plant can take 20% or 30% of intermittent power with close to no extra cost... And the energy mix, the interconnections, the location, the consumption habits all have an impact on the price. Simulation at a grid level, including demand response, thermal storage... can give some precise ideas.
Note that for doing apple to apple we should also include positive and negative externalities
Note that for doing apple to apple we should also include positive and negative externalities