The major driver of renewables costs is investment. The wind blowing and sun shining does not cost anything.
Sadly regarding renewables, there is no twice cheaper available right now. Maybe through innovation somewhere in the future. Right now only hydro power is close to fossil fuel energy density. But it is only available in a few places around the world.
Solar is on par with fosil fuels. And at least in EU with cap & trade system accounting for externalities as well as stopping sponsoring Russian wars and terrorism, I would not be surprised if renewables were twice as cheap.
If a renewable energy source is for example twice cheaper overall including the need to reinvest 25% then it is twice cheaper overall.