Electric Boilers?

EricPeterson

I read this: "Now, Bellingham is looking to do something that no other city has yet attempted: adopt a ban on all residential heating by natural gas."
It's from this article: link
Without getting into an argument about climate change, I am curious as the viability of using a boiler that heats with electricity rather than natural gas.
It seem clear that operating costs would be higher, although efficiency would be higher. Of course any environmental benefit would depend on the source of the generated electricity.
Here in Illinois it would make little sense, but in states where wind / solar / hydro are used, it would be more viable. Such as Washington or Oregon.

Curious,
Eric Peterson

Jellis

1KWh=3,412 BTU
Website I checked said Illinois pays an average of $12.19/KWH

So 3,412BTU costs $12.19

1 Gallon of propane makes 91,000BTU
1 Gallon of #2 oil makes 140,000BTU

You would have to make your electricity really cheap to be a viable option.

Zman

The attached sheet will sort out the math for you. Your best bet is to use an air to air or air to water heat pump and shoot for a COP>3. Air to water units need low temp emitters to become viable, this makes it a no go for existing HW baseboard systems.

Zipper13

At my rates, that heat calc table puts electric at just over double the cost of my ~80% gas boiler....no thanks!

Jamie Hall

There are two aspects to this.

As the gentlemen above have pointed out, it only makes economic sense where you have a system which can use a high performance air to air or air to water heat pump, and where the climate is such that those units can work with a COP or 3 or better. In those cases, air to air or air to water heat pumps can make economic sense. Forced air systems can use them, as can radiant floors. As a retrofit to normal hot water heating or worse, steam, they make no economic sense at all.

As to the climate change or green of whatever aspects, again, they only make sense in locations where either the electricity is generated from wind, solar, hydro or nuclear -- and the environmental downsides of those technologies either have already occurred and are irreversible (most hydro) or can be mitigated. If the electricity is being generated by any form of fossil fuel or renewable fuel (e.g. wood pellets) they don't, unless as mentioned above a heat pump is feasible with COP. of 3 or above. The reason being that thermal power plants -- whatever the fuel -- rarely have a net efficiency to the demand location of more than around 35%; that is, only about 35% of the heat energy released at the power plant makes it to the demand location in the form of electricity. Thus the argument -- often made -- that the efficiency is greater is pure nonsense.

When you factor in the capitol cost of retrofitting all or a substantial portion of the existing building stock, plus reinforcing the electrical grid to handle the additional load, plus constructing the additional generation capacity, the whole concept gets well off into unicorns and rainbows territory.

However, in some circles it sure sounds wonderful...

mattmia2

I wonder what the distribution costs of natural gas, oil, and propane are? Unlike electricity you don't directly lose the product in the distribution (although I think some of the natural gas distribution is natural gas powered) so you usually don't use the fuels uses for distribution as part of the efficiency calculation.

There is a distinction here that needs to be made between electric heating methods. If you say electric boiler, I think an electric resistance boiler. If you mean a heat pump boiler, I would expect you say heat pump or air to water heat pump or something along those lines.

In the electric resistance boiler case, I see little benefit in most cases of that system over direct electric heat emitters in the locations where heat is needed. The heat pump case makes a lot more sense in having a central heating source. Designing for low temp heat emitters isn't that difficult in a new system.

ethicalpaul

> Unlike electricity you don't directly lose the product in the distribution

Oh yeah? Come to NJ and smell the gas lines leaking in every neighborhood 😂

Also no one mentioned water to water heat pump, that would be my choice.

Jamie Hall

Um. Well, if you have a source of water sufficient to extract enough heat from they work well enough..

ethicalpaul

You just need a hole with a loop in it. There’s water under most everything, and it gives you 50 degrees 24/7

mattmia2

The leakage also is not usually accounted for in efficiency calculations...

GroundUp

Jellis said:

1KWh=3,412 BTU
Website I checked said Illinois pays an average of $12.19/KWH

So 3,412BTU costs $12.19

1 Gallon of propane makes 91,000BTU
1 Gallon of #2 oil makes 140,000BTU

You would have to make your electricity really cheap to be a viable option.

Somebody forgot to move a decimal point. 12.19 cents per kwh equals $.1219, or equivalent to $2.93 for the same 82,000 BTU as a propane boiler at 90%.

There is a lot of debate about this subject in my parts, and I install a lot of electric boilers. The rule of thumb I run with is electricity at $.10/kwh is equivalent to $2.50 propane with a HE boiler (within a dime) and for some providers they offer a "dual fuel" rate so if someone has a gas fireplace, furnace, etc as backup they will offer a lower electric rate. Propane hangs around $.75-1.25/gal over the past 10 years here while these dual fuel rates are $.05-.07 depending on the provider, so while it's a bit more expensive to operate the electric boiler, the tradeoff is cheaper installation and no annual boiler maintenance or calling for fuel during a blizzard at whatever today's price might be. The electric rates are a lot less volatile than LP in my neck of the woods, but NG holds pretty steady and is generally about half of what LP costs. My particular electric provider at home is $.14 while the neighbors just 1/4 mile away are on a different provider at $.085, so I choose wood and LP with electric backup in each building.

Jamie Hall

It depends so much on the situation. If one's electricity rate is low, and the power demand is also relatively low, it may make some sense (not from the fuel efficiency/carbon dioxide/green sense unless, as I said, your electricity is not generated by a fuel burning power plant). But... there are other considerations. For example, to replace Cedric I'd need almost 250 amperes at 480 volts 3 phase. Which simply isn't available nearby. At 240 it would be 500 amps, and even if the grid could take it (doubtful) would I really want a 500 amp service entrance?

Then there is what happens when the power goes off. Cedric runs just fine off my generators. I have an idea that a generator big enough to replace Cedric would be an impressive piece of machinery.

EBEBRATT-Ed

Geothermal is fine, it's the cost of the wells that is the problem.

You need something like 3gpm/ton

@ethicalpaul , a hole with a loop in it is a little oversimplified.

In some areas there's rock ledge to drill through, open systems are prone to cause water quality issues, closed loops require a lot of pipe to get enough heat transfer. But they are really nice systems if you can get over the initial costs

ethicalpaul

My driller went through bedrock for 500 feet. Yes it’s an upfront cost for sure.

And @Jamie Hall we know there’s no replacing Cedric!

hot_rod

Jamie Hall said:

It depends so much on the situation. If one's electricity rate is low, and the power demand is also relatively low, it may make some sense (not from the fuel efficiency/carbon dioxide/green sense unless, as I said, your electricity is not generated by a fuel burning power plant). But... there are other considerations. For example, to replace Cedric I'd need almost 250 amperes at 480 volts 3 phase. Which simply isn't available nearby. At 240 it would be 500 amps, and even if the grid could take it (doubtful) would I really want a 500 amp service entrance?

Then there is what happens when the power goes off. Cedric runs just fine off my generators. I have an idea that a generator big enough to replace Cedric would be an impressive piece of machinery.

If you had a consistent thermal load maybe one or two of these.

Gordy

Jellis said:

1KWh=3,412 BTU
Website I checked said Illinois pays an average of $12.19/KWH

So 3,412BTU costs $12.19

1 Gallon of propane makes 91,000BTU
1 Gallon of #2 oil makes 140,000BTU

You would have to make your electricity really cheap to be a viable option.

You mean $ 0.1219 KWH, which equals $3.57 for 100,000 btus which is 29.3 KWH. When compared to NG therms (100,000 btus) as an example.

rick in Alaska

My customer was positive it would be cheaper to heat her two car garage with an electric boiler because she did the math and it worked out. I tried my best to tell her.....
First months electric bill was $400. And she keeps the heat at 50. The second month was cheaper because she shut it off.
In fairness, the bill was for the entire house, but normally it is around 150.
Rick