View - Forest Products Laboratory

					                               FUEL VALUE & POWER CALCULATORS
                         USDA Forest Service       State & Private Forestry Technology Marketing Unit
                  Located at Forest Products Laboratory One Gifford Pinchot Drive Madison, Wisconsin 53726
                                   It might be handy to print this page (currently set for one page)

This spreadsheet contains two worksheets and has no macros. At the bottom of this screen you will see 3 tabs, you are
currently in the instructions. If you select print now you will print these instructions. By pressing the Fuel Calc tab you will
be able to calculate how much you could afford to pay for alternative heating fuels based on your current fuel source, its cost,
and estimated recoverable heating values. Power Calc the other tab gives estimated savings when considering generating
electricity from woody biomass. The calculations in both worksheets are based on the energy in the fuels and their typical
combustion efficiency. They do not consider other costs such as capital or maintenance costs, conversion costs, fuel handling
costs, etc. These would have to be paid for out of the gross margin before any net savings would accrue.

                To calculate Fuel values select the "Fuel Calc" tab at the bottom.
   * Click the yellow box (C24). There should now be a drop down menu
   * From the list, select the fuel you currently use. For example select electricity.
   * Enter what you currently pay for that fuel in the orange box. For example .12
           You will see your current cost per million BTU in blue. For this example that's $35.93
   * Now look at all the types of energy and note how much you could pay for them for the equivalent amount of energy.
           For this example you could afford to pay $206 per ton of green wood to get the same net energy
           People with Propane or electric heat usually benefit the most to switch to something else.
           Note, only J-Firewood has the units "cord"

        To calculate Electric Power values select the "Power Calc" tab at the bottom.
This simple spreadsheet gives estimated values when considering generating electricity from woody biomass.
The spreadsheet examples assume 2 lb of bone-dry wood = 1 kWh (kilowatt-hour)1. Two examples follow:

Example 1: You have a 100-kW (0.1 MW) unit running 12 hour/day, 6 days/week and grid electricity costs 10¢ per kWh.
 Total wood cost is $30 per bone-dry ton (0% moisture content). (You will use about 200 lb of wood each hour.)
 The Margin is about $26,000. Note line 27 that if you were displacing electricty valued at 10 cents ($26.95/mBTU) the
 excess heat would be worth $135,490. If you could capture 25% of that heat and added that value to the electricity,
 that would bring your total margin to about $60,000. If you have no use for waste heat, but could use air-conditioning,
 you could make chilled water using an absorption or adsorption chiller. On line 33 a SEER of 10 is used as the efficiency
 of an older replaced AC unit. If you are replacing a newer AC unit that has a higher SEER the value of your chilled water
  is less. In this example the cooling is worth more than the heat. If all of the waste heat were not converted to cooling
 or if you used more than 25% of the waste heat as heat, then the heat would have a higher value than the cooling.

Example 2: You have a 25 MW unit operating 24 hour/day, 7 days/week, and grid electricity costs 8¢ per kWh. Total wood
 cost is $25 per ton. The wood has a moisture content of 35% (wet basis) so it takes about 3 pounds to make 1kWh.
 50%MC wood would require a little more than 4 pounds to make 1kWh.
 If your displaced heat was $10/millionbtu the value of heat generated would be worth nearly $30 million/yr. If you cannot
 use this heat the value is lost. Consider drying wood or using it for something else. Use absorption chillers in the summer.

Electrical generation is only about 20% efficient, much (25-75%) of the excess heat is available for heat or absorption cooling.
Using this heat makes a huge difference in the economics. A cooling tower or pond is throwing heat ($$) away.

* Your Example - Enter your values in the yellow boxes and the computed answers will appear in the pink section
       The green box is using the BTU value calculated from the Fuel calc sheet.
               If you enter a value in that box you will lose the link, so don't save afterwords if you want to keep that link

Note that maintenance and labor costs are not included in this table. These costs are significant factors!
The initial capital cost of the plant, its expected life, taxes and insurance are also not considered.
The margin would have to cover all these costs in order for the operation to be profitable. Ball park additional = 2-6 cents/kWh
Note also that electricity may be worth more if it is used internally rather than being sold to the grid.
Greater profits are possible when waste heat is used (sold).
Moisture content of woody biomass affects all values and is incorporated into the conversion value.
When you have water, you not only have less wood, you also waste energy turning that water into steam.

1A 25MW plant in Minnesota uses 1.5 tons (at 35% moisture content) of wood per MWh (3 lb = 1kWh).
There is 1.95 lb of bone-dry wood in 3 lb of wood at 35% moisture content (wet basis),
        hence the assumption of 2 lb bone-dry wood = 1kWh.
Plants larger than 25 MW are more efficient (labor etc.), but material hauling costs become the controlling factor.

For more complex related reports see: and
                             FUEL VALUE CALCULATOR
               USDA Forest Service       State & Private Forestry Technology Marketing Unit
        Located at Forest Products Laboratory One Gifford Pinchot Drive Madison, Wisconsin 53726
Your current fuel source is:                    Your cost:
Natural gas                                           $1.40
Your current cost per million BTU is                  $17.07
Alternative fuel sources:                          value:
Wood Green (50% MC)                                       $98
Wood Semidried (30% MC)                                 $153
Wood Air-dried (20% MC)                                 $180
Wood Ovendried (0% MC)                                  $236
Softwood (kiln dried 13% MC)                            $210
Hardwood Wood (kiln dried 8%MC)                         $215
Wood pellets (premium)                                  $232
Natural gas                                            $1.40
Electricity                                           $0.057
Firewood(seasoned 20% MC)                               $261
Switchgrass (ovendried)                                 $212
Bituminous coal                                         $444
Shelled corn (15% MC)                                  $5.36
Fuel Oil #2                                            $1.96
Fuel Oil #6                                            $2.12
Propane                                                $1.23
                                 For this information in a table goto
 vate Forestry Technology Marketing Unit
e Gifford Pinchot Drive Madison, Wisconsin 53726

ation in a table goto
                  Generating Electricity From Woody Biomass
                       USDA Forest Service       State & Private Forestry Technology Marketing Unit
                Located at Forest Products Laboratory One Gifford Pinchot Drive Madison, Wisconsin 53726
                                                      -------------------- Entered values --------------------
    Item                  Units                  Example 1                    Example 2
Size          MW                                     0.1                           25
Operating     Hour/day                                12                           24
Operating     Days/week                                6                            7
Sell price    ¢/kWh                                   10                            8
Cost          Cost of wood/ton                      $30                           $25
Conversion    pound of wood/kWh                     2.0 lb                       3.0 lb
                                                    -------------------- Computed values --------------------
    Item                   Units                 Example 1                    Example 2
Produced      Electricity/year                     374,400 kWh               218,400,000 kWh
Used          Wood/year                                   374 tons                327,600 tons
Value         Electricity/year                    $37,440                    $17,472,000
Cost          Wood/year                           $11,232                     $8,190,000
Margin        Net/year                            $26,208                     $9,282,000
                                                        -------------------- Excess heat --------------------
Excess heat BTU/hr when running                 1,343,000 Btu/hr           335,750,000 Btu/hr
therm/year                                       50,282 therm/yr       29,331,120 therm/yr
millionBTU/yr                                          5,028.19              2,933,112.00
value of heat per million BTU                            $26.95                    $10.00
value of heat available per year                      $135,490                $29,331,120
% efficiency of using that heat                              25                        50
value of heat obtained                                  $33,873               $14,665,560
Margin total (power and heat)                          $60,081              $23,947,560
                                              --All Excess heat converted to chilled water for AC using an absorption chiller--
Cooling from absorption chiller                  940,100 Btu/hr         235,025,000 Btu/hr
Seer rating of replaced AC unit                             10                         13
Kilowattwatts saved rate                                94 kW                  18,079 kW
Kilowattwatthours saved/year                    351,973 kWh/yr         157,936,800 kWh/yr
Value of electricty displaced at Sell price           $35,197                $12,634,944

Value of cool compared to heat                               104%                         86%
om Woody Biomass
stry Technology Marketing Unit
inchot Drive Madison, Wisconsin 53726
 d values --------------------
                       Your problem
                                1           Key in your values in Yellow boxes
                             4.0 lb
ted values --------------------
                       Your problem
                              3,744,000 kWh
                                  7,488 tons 23.9 tons/day
ss heat --------------------
                          13,430,000 Btu/hr
                          502,819 therm/yr
                                   $17.07 uses value calculated from Fuel Calc sheet
ed water for AC using an absorption chiller--
                           9,401,000 Btu/hr
                                   783 kW
                          2,933,112 kWh/yr


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