Water boiling dilemma: electric vs nat. gas

[Piwoslaw]

I've had this dilemma for years: Say I need 1 liter of boiling water. Should I:

1. Pour cold water into a pot and put it on the natural gas stove,
2. Pour cold water into an electric kettle, boil, pour into pot?

(hehe, I finally learned how to use the numbered list option )

Level 1. Boiling water on a stove is less efficient, b/c a lot of heat escapes around the sides of the pot before it can heat the water. In an electric kettle, the heating element is inside and surrounded by water, so the only losses are convection through the sides. Electric wins.
Level 2. I haven't checked which would be cheaper, in the form of how much gas/electricity is needed for either and how much it would cost. This level interests me the least.
Level 3. Electricity here comes mostly (90%-95%) from old, coal-fired powerplants. Natural gas burns much cleaner. Gas wins.
Level 4. Gas comes mostly (80%) from Russian wells in Siberia, going thousands of kilometers, transiting Belarus and Ukraine, giving them and Russia the power to blackmail other countries just by closing a valve (which they do quite often recently). Coal comes from Polish coal mines, some of them underground, others are strip mines. Neither wins.

Recently I've developed the habit of boiling water in the electric kettle and pouring it into the pot. In my opinion this is more efficient energywise, reduces the dependence on foreign energy sources, and potentially more ecological. I stressed potentially, b/c it is possible to increase the amount of RE in the grid (in fact, Poland is obligated to do so, but isn't doing much about it ).

Any comments, suggestions, advice?

[dcb]

Microwave it

Actually for small amounts of water the microwave can be more efficient, since you don't have to heat the pot or kettle. Not sure where the break even point is.

[Frank Lee]

As an aside, I always put a frying pan on top of pots I boil water in. I have an electric stove and the increased weight definitely improves the contact between pot and element and so heats up faster. Also I ignore directions that call for boiling uncovered. I don't understand why they call for that? AND, say I'm making pasta- I ignore their suggested amount of water per quantity of pasta; it's always too much. By 1. using a smaller amount of water, it comes to a boil much faster 2. covering the pot with heavy pan retains heat and improves burner contact (for electrics anyway) even better than using the designated lid 3. I throw the pasta in, put the pan back on top, and turn the burner OFF. Yes, the whole cooking process is done with the burner off! It works. 4. That way I don't have to stand there and babysit it. I go off, get the mail or surf a forum for 5-10 minutes, come back to it, and it's done. The whole process is actually faster my way too, mainly from the quicker bringing to boil of the smaller quantity of water. 5. I don't steam up the kitchen very much either. Don't need to use the range hood vent- yet another power savings. And then that doesn't draw my warm heated indoor air and throw it outside- yet another savings. Domino effect!

[dcb]

Yes, don't put more water in the pot than you absolutely need. I'm like Justin Wilson with the spices when it comes to filling the tea kettle just right

[Peter7307]

Originally Posted by dcb

Microwave it

Actually for small amounts of water the microwave can be more efficient, since you don't have to heat the pot or kettle. Not sure where the break even point is.

I would do the same.

Actually heating a small amount of water is a real nuisance.
I have an electric jug but it needs about three cups and normally I only need one cup hot for tea or coffee so the microwave is the clear winner.

I know it still uses coal generated electricity but here gas is used for heating houses etc and coal for generating power.
I suspect that will change as time goes by and we switch to more renewable sources.

If the choice is gas on stove top or electric jug and the pour into pot ;I think your choice of electric jug is the better option.
There is some chance of using renewable energy and the overall efficiency would be higher as well.

As an aside why are electric jugs not better insulated?
The one I have is about as hot to touch as the contents are.
Maybe a combination of thermos and electric jug would work.
Any thoughts?

Cheers , Pete.

[Bicycle Bob]

Typically, 2/3 to 3/4 of the heat in the coal is wasted before it gets to the electric kettle. An instantaneous gas-fired water heater would be 80-95% efficient. A heat-pump based heater could be powered with gas or electricity for higher overall efficencies. For small quantities, a Kelly kettle (with internal chimney) on a gas ring can be very good, and gas gives off much less carbon per therm than coal.

[Piwoslaw]

Originally Posted by Peter7307

As an aside why are electric jugs not better insulated?
The one I have is about as hot to touch as the contents are.
Maybe a combination of thermos and electric jug would work.
Any thoughts?

I think that insulating it wouldn't save that much, since the jug is used for quick boiling, not for holding hot water for a longer time. Maybe I'll do an experiment with my kill-a-watt-oid and see how much electricity is really needed to boil the same amount of water in the microwave, in an electric kettle, and in an electric kettle with a blanket wrapped around it. I'd also like to see how much gas I use for boiling on the stove, but the gas company has the key to my meter :/

Like you all mentioned, I try not to boil more water than I need. My electric jug has a minimum of 0.5 liters, but I usually pour slightly less when boiling water for 1 cup. I also more or less know how much is need for 2 cups. I've told the Wife about all this and she also tries to do the same, but my Dad-in-law just pours in water without looking (usually 3-4x too much), turns it on and goes somewhere. By the time he gets back the water is barely warm, so he pours in more and boils again, eh I think a good idea would be to draw lines on the water gauge on the side and number them: 1 cup, 2 cups, etc. Make it big and red, darnit!!

[Piwoslaw]

Did a test, here's what I got:
I boiled 500ml of room temperature (18*C) tap water in an electric kettle, in the same kettle while holding a fleece blanket around it, in the microwave, and in a small pot on the stove.
Kettle: 1960 watts, 3 minutes, used 58Wh.
Kettle with blankie: 1960 watts, 3 minutes, used 57Wh.
Microwave: 1360 watts, 6 minutes, used 109Wh.
Stove: 6 minutes.

Comments:
Kettle with blankie: After the first boil I poured out the water and waited 20 minutes for the kettle to cool down. During the second boil I held a blanket around the sides of the kettle. As expected didn't really help. After the 3 minutes, the sides of the kettle were barely luke warm.
Microwave: The water was in a Pyrex glass cup. The 1360 watts includes extras like: dispay (3W), light (40W), turntable and fan (?W).
Stove: Read in the stove's instruction that the burner is 58% efficient. Found a way to open the box with my meter, but it didn't budge during the test, so I either used less than the meter's resolution of 0.0001 cubic meters, or the stream was too weak to overcome the meter's internal resistance. Maybe a test with boiling 5 or 10 liters would give something?

The outcome is clear: just keep boiling in the electric jug, as I've been doing. I was kind of hoping the microwave would be more efficient for a small amount of water, but it appears that even without the parasitic loads it won't work. Maybe a newer unit would be more efficient?

[dcb]

cool

Though Bob raises a good point. For example, if you have natural gas to your house and the electric company uses natural gas to make electricity, it should in theory be most efficient (energy wise) to "cook with gas" directly rather than convert the gas to electricity.

[Ryland]

We have a Hamilton Beach (Proctor Silex, Inc.) double wall insulated water heating pot with an insulated lid as well, I really like it because it has a toaster style switch to turn it on and it turns it's self off when the water starts to boil and it will boil as little as a half cup up to about 4 cups of water at a time, When I put the Kill-a-watt on and dumped in 500ml (just over 2 cups) of water it took .05KWH of electricity to heat the water to a nice boil and to trip the shut off switch, our electrical rate is 10 cents per kwh and I figured two pots of tea per day were less then $.30 per month.