GBlist: electric heating versus oil / example

["Bion D. Howard" <bdhoward@ix.netcom.com>]

To:  Bob Taylor
cc:  Greenbuilding List FYI
----------------------------------------------------
At 05:08 PM 1/28/2000 -0800, you wrote:
>we built a house in Alaska that used 214 gallons #1 stove oil per  year
for heating.
>
>I need convert BTU/gallon to KWH to know how much electricity my former
house would use for heating.
----------------------------------------------------

1.  Heat content of  Res. Fuel Oil ~  139,000 Btu/Gal

2.  Efficiency of heating system =     N   =   ( nm  *  nd )
                 where:
     mechanical efficiency of furnace, boiler...  =   nm
             (range  0.65 to 0.94 typ)  
     operating efficiency of distribution ducts    =   nd
           (range 0.6 - leaky -  to  0.95 - tight -  )  

3.  Site Btu per kWh electric  =  3,413

thus:    kWh (site @)  =  

  ( [ (Gallons FO * Btu/gal)  /  N ] / system COP ) / 3,413   Btu/kwh

   @ energy on "site" is a form of secondary energy...

  while the above "source" energy based on typical coal fired power plant.

               10,500 / 3413 =  3.076 (typ. factor)

let's convert to electric power equivalent (assumes similar efficiency
levels for equivalent electric power equipment  !!!!  in AK air-source-
heat pumps are not a good choice, except maybe Homer, Valdez, Juneau,
Ketchikan (sp.?) and coast areas where sea surface temps dominate weather....)
  
So, may be the house might have had -- horrors -- electric resistance strip
heaters in AHU.  Then there is a one to one conversion.  If the was a heat
pump involved then there would be a coefficient of performance (albeit low)
to content with...

       Example (reasonably good new home):
======================================
     Consumption  =  214 Gallons
     Mechanical plant efficiency =  82%  (efficiency 0.82)
     Duct loss rate = 10%                           (efficiency 0.90)
     Direct electric heat alt.  =  1.0 (assumed in example)
     Heat pump heating alt.    = 1.7  (revised COP)
       (COP - ratio of heat into system vs. work performed)

 So Equiv. kWh:       

       kWh (site @)  =  
 (  [ ( 214 * 139,000 ) / (0.82 * 0.90) ] / COP=1 ) / 3,413 Btu/kwh
	=  40,306,233 / 3,413
	=  11,810    kWh - site 
               (~  $940 of electricity @ $0.08/kWh)

       kWh (equiv. source)  =    kWh (site) * (10,500 / 3413)
	=  11,810  * 3.076
	=  36327.56   kWh - source

   Also, your home would have used about

            40,306,233 Btu * 3.076 =  123,981,973 Btu

  of equivalent source energy had it been traced back to power plant in
this example.

Notes @ -----

Actual electric power heat rates vary from about 8,900 to over 14,000
Btu/kWh (in some cases).
The low end might represent a mix of coal, nuke, and hydro; high end coal
with large transmission and dist.losses.

Sometimes a phone call to your elect. utility (engineering section...) will
put you in touch with someone who knows the service territory "heat rate"
for your electric power.  This data is reported periodically to the
National Association of Regulatory Utility Commissioners (NARUC) in
Washington, DC.  Sometimes your state PUC will have this data too.

Source energy includes the inefficiency of energy conversion, transmission,
distribution losses to account back to the power plant for environmental
impact on atmosphere.  

Def -  "Primary energy source" - Energy source used directly to produce
heat, light, or motion. 
Primary energy sources are fossil fuels, geothermal, nuclear, solar, and
tidal.

Pollution Avoidance
================
      (from)  Table 2: NOx and CO2 Emission Rates by Fuel Source
   ______________________________________________
   |   Pollution data        NOx Emissions      CO2 Emissions 	|
   |   		        (lb./mmBtu)         (lbs. carbon/mmBtu)	|
   |_____________________________________________|
   |    Hvy Fuel Oil             0.05 -  >1                   47 	          	|
   |	Coal	             0.1 - > 2                     56		|
   |    Natural Gas              0.005 - >1                   32		|
   ---------------------------------------------------------------------

   So for above house heating example:   
                     -- CO2 only  emissions comparison --
       Electric house =  124 mmBtu * 56 / 2000 =  3.47 Tons
       Fuel Oil house =    40 mmBtu * 47 / 2000 =  0.94 Tons

---------------------------------------------
                                  Avoided CO2 (example)          2.47 Tons

---------------------------
    Table Source: Congressional Research Service
      Report for Congress 98-615: 
      "Electricity Restructuring: The Implications for Air Quality"
          By:  Larry Parker and John Blodgett
    Specialists,  Environment and Natural Resources Policy Division
    <http://www.cnie.org/nle/eng-43.html#_1_7>

Tool ====
Energy savings pollution avoidance "calculator"
         (scroll down, on left)
   <http://www.energybuilder.com/ftp-resource.htm>

===========

    ||       Contact:  Bion D. Howard, President
=(O) =     Building Environmental Science & Technology
    ||      P.O. Box 1107   Edgewater, MD 21037  USA
         Phone:  410.867.8000   Telefax: 301-889-0889
<mailto:bdhoward@ix.netcom.com>  <http://www.energybuilder.com>
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