A little OT: electric kettle versus kettle on induction ring

It implies the gas kettle is good at capturing the heat as the hob is just burning 100% of the gas.

Not exactly a lab comparison, but this guy reckons the total energy efficiencies of boiling water on a gas hob or in an electric kettle are about the same. But as with so many things these days, the result you get depends on the initial assumptions you make, in this case on the efficiency of the generating and transmission process.

OK but you have to supply some information..

what's it made from what's the wall thickness what's the dimensions what is the surface texture are there any draughts how much water do you boil how much is left how long between boils

That's the easy one.. the sun and a supernova.

Thats not even a kettle designed for gas, most of the heat would just go up the sides.

This is a kettle designed for gas, you may notice the heat exchanger lets the flame in to capture more of the heat.

I'd be surprised. In a small kitchen, boiling anything on a gas hob tends to increase the temperature in the room. Not sure I've ever noticed that with an electric kettle.

You might if the 60-65% inefficiency of a power station was directed into your kitchen (in proportion to the power you were using, of course).

Which is probably why the guy found that a small flame was more efficient than a larger one. Less of the heat lost up the sides, more absorbed by the water.

Working out the true efficiency of any domestic power source accurately is impossible. Far too many variables. Even within the same day.

But the longer it takes to reach boiling point, the greater any heat losses become as a percentage.

Well, quite, but you can make a reasonable estimate. Hence my 60-65%. We're not looking for three-decimal-place accuracy! My point still stands. The heat from a gas ring that doesn't go into the water goes into the kitchen. The heat from a power station furnace that doesn't go into generating electricity goes up the chimney.

That assumes all power generation is by gas. Or, indeed, heat. Then there's how much energy is needed to get the gas out of the ground, transport it, etc.

Assumes nothing of the sort. My point still stands. The reason a kitchen gets hot when boiling a kettle with gas but not with electricity is because the waste heat from generating electricity is dissipated elsewhere.

Steam from the cooling towers, Shirley?

water vapour -

'up the chimney' was just a turn of phrase. Wherever it goes, it doesn't end up in DP's kitchen, unlike the waste heat when he boils a kettle on gas.

Sorry - but don't get that. Suppose I have suitable solar panels and the sun is shining and I use that electricity to boil the kettle? Or lived in a country where much of the power is hydro?

For the purposes of this discussion, the word "steam" is adequate. What goes up the chimney is the exhaust gases from the combustion process (which will include some steam). The main exit for waste heat, I would say, is the steam exiting up the cooling towers (from the water used for cooling). Why else would a power station with one chimney have several cooling towers?

Roger that.

Then the total efficiency of the electric kettle would be much greater than that of the gas heated kettle. But the guy I linked to was saying that the total efficiencies, gas vs. electric, were about the same, because he was including the heat wasted in generating the electricity and from transmission lines, i.e. 64% was wasted, so he assumed was electric was only 36% efficient before it even got to his kettle. As I said in my post, the result you get depends on the initial assumptions you make, in this case on the efficiency of the generating and transmission process.