https://en.wikipedia.org/wiki/Peaking_power_plant

100% renewable in 10 years may be ambitious, but an 80% renewable grid is easily affordable. Even France is only 80% nuclear and balances with cheaper sources like natural gas. While reactionaries use it as a straw man cheaper option.

https://en.wikipedia.org/wiki/Power-to-gas#Storage_function

And with power to gas the grid can be 100% renewable without needing better batteries. There is no storage problem. The grid is already backed up for months.

https://www.pickhvac.com/faq/singal-stage-vs-two-stage-for-heat-pumpac/

And for most a gas furnace is not the cleanest heating option. Two-stage air source heat pumps have equivalent efficiencies with a COP of 4, keep their efficiency down to 0f (-18c), cost less than a furnace+a/c, and can be powered by 100% clean energy.