You are making the mistake of thinking that if the grid could provide 100% renewable energy on a windy day at noon in summer, it could also provide 100% renewable energy at night in winter with no wind. Obviously that’s not accurate. Renewables provide energy in a highly volatile sine wave. It’s the bottom of the sine wave which determines the capacity required for base load and dispatchable generation, not the top of the wave.

[Gas is about 11-13x cheaper than renewables with externalities like grid restructure and volatility imputed.](https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4028640) That’s not to say renewables don’t have their place in modern grids. In fact an optimal allocation is around 80% renewable in the UK. However, until battery storage becomes about 95% cheaper, it would be ASTRONOMICALLY expensive to make the grid 100% renewable. Trillions of pounds in the UK. An order of magnitude more expensive than just paying higher gas prices.

People often make the mistake of thinking that because wind and sun is free, the cost of energy generation is basically free. Those people don’t understand how many fixed and marginal costs there are. If you’re interested, the paper above provides good insights into those costs.