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					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 (C23). 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 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, and taxes are also not considered. The margin would have to cover all these costs in order for the operation to be profitable. 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:
http://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr157.pdf and http://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr157/biomax_10.xls

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 Item Size Operating Operating Sell price Cost Conversion Item Produced Used Value Cost Margin Units MW Hour/day Days/week ¢/kWh Cost of wood/ton pound of wood/kWh Units Electricity/year Wood/year Electricity/year Wood/year Net/year -------------------- Entered values -------------------Example 1 Example 2 Your problem 0.1 25 1 12 24 24 6 7 6 10 8 12 $30 $25 $35 2.0 lb 3.0 lb 3.4 lb -------------------- Computed values -------------------Example 1 Example 2 Your problem 374,400 kWh 218,400,000 kWh 7,488,000 kWh 374 tons 327,600 tons 12,730 tons $37,440 $17,472,000 $898,560 $11,232 $8,190,000 $445,536 $26,208 $9,282,000 $453,024 -------------------- Excess heat -------------------1,343,000 Btu/hr 335,750,000 Btu/hr 13,430,000 Btu/hr 50,282 therm/yr 5,028.19 $26.95 $135,490 25 $33,873 29,331,120 therm/yr 2,933,112.00 $10.00 $29,331,120 50 $14,665,560 1,005,638 therm/yr 100,563.84 $17.07 $1,716,944 50 $858,472

Excess heat BTU/hr when running

therm/year millionBTU/yr value of heat per million BTU value of heat available per year % efficiency of using that heat value of heat obtained Margin total

$60,081

$23,947,560

$1,311,496

Biomass

ng Unit Wisconsin 53726

40.7 tons/day

uses value calculated from Fuel Calc sheet


				
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