Much more than 60% to go, as all the non-electricity fossil fuel use (heating, transport, industry) will also need to be replaced by emissions free electric alternatives.
On the bright side, this makes intermediate progress simpler in some ways.
You can replace say, gas powered heating with heat pumps and transfer the gas to storage for use in electric generators for when demand and supply diverge.
These transitions can be done in parallel but once you hit a certain degree of carbon free electricity it makes sense to redirect focus to shift towards electrification as things that may have been borderline become viable.
Solar water heaters. And district heating that uses waste heat. (E.g. waste heat from data centers or industrial processes).
Besides that you could run smelting ovens, internal combustion engines, and other furnaces of hydrogen. Though that hydrogen will probably come from electricity if it isn't polluting.
Yeah I roughly guesstimate we need about 4 to 5 times as much as we currently have installed. Bright side is the various technologies we need are developed and in production.
