Sure, if your only source of electricity is fossil fuels like natural gas, then just burning them directly is better when heat is all you want. But if you have renewable sources of electricity, isn't that better than using fossil fuels at all even if it is technically less efficient?
Yeah, exactly. If everyone has gas stoves you need gas, if you have electric there can be more sources of energy, and to a certain extent electricity if fungible across multiple sources (if you have power plants).
Devil is in the details. Peaker plants are almost always natural gas, and I'd expect an electric oven (high power appliance that immediately turns on when you turn it on, and immediately turns off when turned off) is most likely using electricity from a peaker plant, rather than a baseload plant.
The peaker plant/base load choice is based on aggregate load though, the power provider has little to no knowledge of what appliances households are using. An electric stove, and realistically anything else that uses electricity, is therefore using one or the other based on the usage pattern of the whole customer base at that time.
If you turn on your electric stove at 3pm, when the grid is stressed from the afternoon sun, your electricity is almost certainly coming from a peaker plant (unless you're in California, at which point the peaker-plants are coming on at 6pm or so).
If you turn on your electric stove at 2am in the middle of the night, the grid is almost not being used at all, and cheaper nuclear power / baseload plants are probably what powers your stove.
--------
Its not so much "The Grid has 30% renewable energy on the average". Its "At 2pm, the grid is mostly non-renewable due to the number of peaker plants" and "at 2am the grid is mostly renewable nuclear"
As solar panels get deployed, the times will change, but the concept won't change. Peaker plants are the only plants that can respond to consumers. Anyone using electricity at times outside of what renewable energies can provide will effectively be using natural gas.
>If you turn on your electric stove at 3pm, when the grid is stressed from the afternoon sun, your electricity is almost certainly coming from a peaker plant (unless you're in California, at which point the peaker-plants are coming on at 6pm or so).
For California, you can check the actual generation mix:
