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Thread: Price of NG vs Elec Heat

  1. #1
    I&C Engineer (mostly WWTP) Lakee911's Avatar
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    Default Price of NG vs Elec Heat

    So, in my area I have a choice between Electric (Elec.) and Natural Gas (NG) and my rates are as follows:

    NG: $13.68 flat rate + $0.9691/CCF
    Elec: $452 flat rate + $0.116/KW-Hr

    I'm trying to determine which one is cheaper to use for heating. I know that effeciency of the natural gas heating device will come into play.

    I have found the following conversions online:

    1 KW = 3,414.43 BTU/Hr therefore 1 KW-Hr = 3414.43 BTU
    1 CCF-NG = 103,100 BTU

    When I assume an 80% effeciency (on NG), I get $3.40 for Elec and $1.17 for NG (neglecting flat rate). That's almost 1/3 of the price for NG.

    I'm confused on the units though...is that for 1 hour of burn time?

    Thx,
    Jason

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    Retired Defense Industry Engineer jadnashua's Avatar
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    BTU/hr and Kw/hr, so yes, I think you have the right values. It is a rare place whose electric rates are cheaper to use for heating than natural gas (they do exist though). And, there are furnaces and boilers that do much better than 80% efficiency - mid-90% is readily available, but depending on the inflation of energy costs, may or may not have a reasonable payback period, if any. It could be said that electric is 100% efficient, and you'd be close, but if you take how that electricity was generated, burning NG at home in a high-efficiency unit probably beats it in delivered efficiency counting the production, distribution losses, and local losses.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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    I&C Engineer (mostly WWTP) Lakee911's Avatar
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    Thanks, Jim. I would consider electric to be nearly 100% effecient. If not, I would accept above 99%. I don't care about the losses associated with that because they are before my meter.

    I still find it surprising because my NG price is very low, and it is still a big difference.

    Thanks,
    Jason

  4. #4
    In the trades Dana's Avatar
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    Quote Originally Posted by Lakee911 View Post
    Thanks, Jim. I would consider electric to be nearly 100% effecient. If not, I would accept above 99%. I don't care about the losses associated with that because they are before my meter.

    I still find it surprising because my NG price is very low, and it is still a big difference.

    Thanks,
    Jason
    The average fossil-fired generator is ~30% efficient when looking at generator-fuel-BTUs-in vs. kwh dissipated at the end load, it should be no real shocker, eh? (Over half of the input BTUs at the plant go up the flues & cooling stacks, well before the primary winding of the first transformer. The very best noo-improoved combined cycle generator technology is about 60% efficient to the first transformer, and loses another 3-7% in grid losses.)

    (For heating purposes electricity can be considered 99.9%+ efficient between your meter and the elements- losses in the house wiring is heat delivered inside conditioned space.)

    The only way electricity can usually compete with NG is with heat pumps delivering a COP of 3.0. But both NG and electricity prices vary widely with region/supplier. Already-paid-for hydro & nukes are a lot cheaper than any form of new generating capacity, and fossil plants all suffer volatile fuel pricing issues.

    NG is down this year and may stay down for awhile, as N. American proven reserves has expanded greatly with new technology, with a lot of coal seam & shale goods coming on line. Carbon taxes will favor NG over coal 2:1, so it may become the fuel of choice for any new fossil plants going forward- the prices will eventually rebound, but it may take awhile.

    The most efficient use of NG for power generation is in combined heat/power cogeneration. There is at least one vendor of a household scale gas cogen using Honda technology at it's core. They combine it as a packaged unit with either a condensing furnace or condensing boiler to handle the full thermal load. It's price competitive with condensing boilers alone, but is a bit of a cost-adder for hot-air furnace configurations (but still has a very good internal return rate where net-metering is allowed.) See: http://www.freewatt.com/

    The guy in the office next to me has the Freewatt cogen in his house. Since he lives in $0.22/kwh country the payback is pretty fast for him!

    In Germany they've taken the home-scale cogenerator up an order of magnitude with VW- powered generators supporting the entire thermal load of the house unassisted, wiping out the electric bill entirely while turning it into a net power supplier to the grid. The cogen is controlled remotely by the utility, the building owner pays the fuel, the utility pays the maintenance. It's price competitive with high efficiency heating systems, but with a much bigger payback for the homeowner (no power bill? Kewl!) See:

    http://www.lichtblick.de/h/ZuhauseKraftwerk_310.php

    http://www.lichtblick.de/h/technik_291.php

    With either of these systems you end up with 95%+ net fuel-BTU efficiency, since the heat is used by the building instead of sent up the flue, and the grid losses are near-zero (most of the power is consumed 1-transformer or fewer from the source.) You could get that much efficiency out of just a high efficiency heating system, but without the premium quality benefit: The electrical power. With juice included the economics start looking pretty good. (I'd be doing it, except for the fact that the boiler supplied with the Freewatt is by itself 3-4x oversized for my heat load. I'm on their list, should they ever bundle it with something tiny enough. I expect they'll have competition soon enough...)

  5. #5
    Moderator & Master Plumber hj's Avatar
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    Default heat

    Unless you live in an area such as the TVA with heavily subsidized electric rates, electric heating will not come close to the cost of using gas.

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    Homeowner Thatguy's Avatar
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    Quote Originally Posted by Lakee911 View Post
    So, in my area I have a choice between Electric (Elec.) and Natural Gas (NG) and my rates are as follows:

    NG: $13.68 flat rate + $0.9691/CCF
    Elec: $452 flat rate + $0.116/KW-Hr

    I'm trying to determine which one is cheaper to use for heating. I know that effeciency of the natural gas heating device will come into play.

    I have found the following conversions online:

    1 KW = 3,414.43 BTU/Hr therefore 1 KW-Hr = 3414.43 BTU
    1 CCF-NG = 103,100 BTU

    When I assume an 80% effeciency (on NG), I get $3.40 for Elec and $1.17 for NG (neglecting flat rate). That's almost 1/3 of the price for NG.

    I'm confused on the units though...is that for 1 hour of burn time?

    Thx,
    Jason
    Assuming 100% efficiency, 1 Therm of energy can be had from approx. 100 cubic feet of natural gas, 29 kwh of elec heat, 8.4 kwh of heat pump heat (COP = 3.5), 4.2 kwh of heat pump heat (COP = 6.9).

    So you pay $1.17 per therm of energy for NG and $3.40 per therm of energy supplied by elec.

    If you used the 29 kwh of elec. in one minute you'd be consuming this chunk of energy at the rate of 1740 kw.

  7. #7
    I&C Engineer (mostly WWTP) Lakee911's Avatar
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    Freewatt thing sounds kind of neat. There isn't a dealer within 100miles though.

    I don't think Ohio is setup for cogen to have any significant benefit to the consumer, but there is some talk about net metering that might make it more attractive..

    Thanks.

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    In the trades Dana's Avatar
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    Quote Originally Posted by Lakee911 View Post
    Freewatt thing sounds kind of neat. There isn't a dealer within 100miles though.

    I don't think Ohio is setup for cogen to have any significant benefit to the consumer, but there is some talk about net metering that might make it more attractive..

    Thanks.
    Don't rely on their online dealer finder. I live less than 40 miles from their headquarters, yet the online tool tells me there's nobody covering my area (despite the fact that I had them on-site for an evaluation a coupla summers back.)

    Call/email them.

  9. #9
    DIY Senior Member zl700's Avatar
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    "The most efficient use of NG for power generation is in combined heat/power cogeneration. There is at least one vendor of a household scale gas cogen using Honda technology at it's core. They combine it as a packaged unit with either a condensing furnace or condensing boiler to handle the full thermal load. It's price competitive with condensing boilers alone, but is a bit of a cost-adder for hot-air furnace configurations (but still has a very good internal return rate where net-metering is allowed.)"

    Should note:

    With the FreeWatt producing 12,000 BTU's of heat, one there must be a need for that to be consumed to have the unit running, and it only produces 1500 Watts of electric so not much, but it's purpose is to run/operate the means of heat dispersion. Assuming there are appliances, cable boxes, alarm clocks, etc. any power produced that's left over would be quickly consumed, thus a net-meter would not help, if at all.

  10. #10
    In the Trades Wally Hays's Avatar
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    1/3 the cost of electric is pretty much the norm and has been for many years.

  11. #11
    DIY Senior Member Runs with bison's Avatar
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    Quote Originally Posted by zl700 View Post
    With the FreeWatt producing 12,000 BTU's of heat, one there must be a need for that to be consumed to have the unit running, and it only produces 1500 Watts of electric so not much, but it's purpose is to run/operate the means of heat dispersion. Assuming there are appliances, cable boxes, alarm clocks, etc. any power produced that's left over would be quickly consumed, thus a net-meter would not help, if at all.
    1500 watts is over twice my average daily consumption rate (which breaks down to about 600-700 watts). For the 4 coldest months of the year the heat load would be needed and I would need net metering.

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