Abstract: Co-utilization of relatively small amounts of dedicated Energy Crops (such as fast growing Eucalyptus and Cottonwood trees) with coal at existing base load power generation stations, may provide Electric Utilities with a cost attractive option in:

· Achieving National Energy Policy objectives to reduce Greenhouse gas emissions.
· Complying With Potential Renewable Energy Portfolio Standards (i.e., deregulation)
· Supplying Electricity Customers with a "Green Energy" Purchasing Option.

The primary cost advantage of Energy Crop Co-utilization, versus other Renewable Energy options such as Solar Energy, is the use of a power generation station's existing infrastructure (i.e., boiler, turbine/generator), thus avoiding the high capital cost per KW of building new stand alone facilities. In Energy Crop Co-Firing, either new (for Pulverized Coal boilers) or modified (for Cyclone Units) fuel delivery system would be implemented (i.e., direct injection, or external on-site gasification), providing approximately 3 to 8 percent of the overall fuel-mix (based on heat input) through a renewable biomass fuel feedstock. While Energy Crop Co-Firing is a "fuel switching" strategy and does not create new MW capacity, Co-Firing does create a "new" Renewable and Sustainable Energy Resource.

An Energy Crop Co-Firing Program has the ability to reduce overall Greenhouse gas levels in two ways: First, in the displacement of coal use by substituting "carbon cycle neutral" biomass fuels; second, through long-term carbon sequestration at the Energy Crop Plantation Site. This second point is extremely important, as approximately fifty percent of the total carbon sequestration through tree growth occurs below the ground level, in the tree's root system. Thus, when trees are harvested as Energy Crops, approximately 50% of total carbon sequestered by the trees would remain in the soil.

Because of the tremendous size of typical base-load, coal-fired generating Units, co-firing relatively low levels of Energy Crops can have a tremendous environmental impact. An illustration of this point is Lakeland Electric's ~ 365 MW McIntosh 3 Generating Station (pulverized coal). A three percent (3% by heat input) co-firing level at McIntosh would have the equivalent effect of removing over 30,000 vehicles off the roads, which would represent approximately 23% of all vehicles in Lakeland Electric's electricity service area.

Introduction: The scope of this paper is to establish the methodology and to develop scientifically based estimates of the impact for CO2 reduction and sequestration of a potential Energy Crop co-firing program for these power generation stations.

Co-Firing: With biomass co-firing, a percentage of fossil fuel use at an existing utility power plant is displaced with the "biomass energy crop" fuel. The Energy Crop Plantation would be sited in close proximity to the power plant (where the energy crop fuel would have a significant transportation cost advantage to coal delivered from Appalachian and Western States). For example, at a 10% co-firing ratio, a coal fired power plant's fuel mix would change from a 100% current use of fossil fuels, to 90% fossil fuels and 10% energy crop fuel. Given the tremendous size (MWs) of utility power plants, relatively small percentages of biomass co-firing can have significant environmental impacts on numerous air emission issues, including: Potential Global Warming/Climate Change (CO2), Acid Rain (SO2), and possibly Smog (NOx).

A significant competitive benefit of the co-utilization of biomass fuel at existing power plants is the potential minimal capital cost per KW associated with a co-firing Program. Compared to other potential sources of Renewable Energy (i.e., specifically solar) which require new stand-alone facilities, biomass co-firing utilizes the existing infrastructure of a base or intermediate load power plant (i.e., boiler, turbine/generator, etc.).

Based on previous "Biomass Co-Firing Test Burns" (conducted at major power plants in Florida and other States through U.S. Department of Energy sponsored research), the range of acceptable co-firing levels (that would not negatively impact current operations) is approximately 3% to 10%. Also, prospective coal fired units in which biomass co-firing would occur, are base-load units with an availability factor of ~80%. For example, a 3% co-firing ratio at FPC's Crystal River Unit 4 (~740 MW Nameplate) would produce the equivalent of 22 MWs and ~155,000 MWHs annually (assuming a capacity factor of 80%). It must be emphasized that with biomass co-firing at existing coal units, while a new "Green Energy" resource would be created, no new additional generation capacity (MWs) is created. Biomass co-firing simply changes the overall fuel mix at an existing generation station.

Environmental Benefits of Energy Crops: Utilization of Energy Crops has significant environmental benefits in a number of potential areas:

· CO2 Emissions (by creating agriculture carbon sinks).
· Acid Rain (biomass contains almost no sulfur).
· Potential Smog Reduction (biomass contains about 50% the nitrogen content of coal).
· Water Remediation (i.e., urban generated wastewater, sewage effluents).

In general, biomass used for producing energy is CO2 neutral. Growing plants sequester CO2, thereby mitigating greenhouse gases. When biomass is converted to energy use, stored CO2 is released, resulting in zero net CO2 emissions. Fossil fuel use, in comparison increases net CO2 emissions.

Florida is very favorably positioned to reduce CO2 emissions through the use of Energy Crops as a fuel feedstock for electricity production. Because of the State's long growing season, high rainfall, and available land base, Florida can produce exceptionally large quantities of Energy Crop Biomass, harvested in crop rotations of 2 to 4 years. Crop species are quite varied and include a number of fast-growing trees such as Eucalyptus (non-invasive) and also Cottonwoods (native to the State) suited to energywood plantations. An especially favorable carbon balance is achieved when energywood plantations are established on previously non-forest sites, such as closed phosphate mining sites located in Central Florida.

In addition, an energywood plantation can be a long-term resource, as Energy Crops re-grow from the stump after harvest (called "coppice"), allowing between 5 and 6 harvests from the original seeding planted. This rapid re-growth quickly return the plantation to its CO2 sequestration mode, without the need for any further energy inputs for plantation management. In addition, as trees grow, ~50 percent of the carbon sequestered is contained below the ground in the tree's root system. This fact has significant implications in Energy Crop biomass co-firing use, as the Energy Crops not only will displace emissions CO2 of coal, but also provide for the long-term sequestration of carbon through their root system (improving the organics of the soil).

As a further environmental benefit, Energy Crop trees can be irrigated with nutrient-containing waste-waters and/or amended with compost/yard waste. A site example of this type of plantation setting is Orlando Utilities (a 40% co-owner of the McIntosh #3 Power Station)Water Conserv II Project. Irrigation and compost rates can be as high as 25 gallons of wastewater/day/tree and a one-time 45 dry tons/acre of compost, respectively, but both can be set to meet the environmental concerns at the Plantation Site. No herbicides need to be applied if sufficient mechanical site preparation (disking/rotovating/bedding) is done, no fertilizing is needed after planting, and no pesticides typically need to be applied.

Eucalyptus Grandis, the fastest growing energywood species in Florida, is not invasive. It has been commercially planted since the 1960's at low density (600 trees/acre) in rotations of 8-12 years on approximately 15,000 acres in Florida with any record of escape. Further, the high planting density (1,100 trees/acre) in short rotation (2 to 4 years) virtually eliminates any potential for the trees to flower.

Step 1: Calculation Of Coal Displacement Through Biomass Co-Firing

(1) Capacity of Generating Station Unit (in KW)
(2) Capacity Factor Assumed For Unit (in percent)
(3) Unit's Number Of Yearly Operating Hours = (24 hrs.* 365 days * Item [2])
(4) Yearly KWH Produced At Unit = (Item [1] * Item [3])
(5) Heat Rate Of Unit (BTUs required to produce 1 KWH)
(6) Total Input MMBTUs For Unit = ((Item [4] * Item [5])/1,000,000)
(7) BTU Content Of Coal Per Pound (as received)
(8) MMBTU Content Of Coal Per Ton = (Item [7] * 2,000)/1,000,000
(9) Biomass Co-Firing Ratio For Unit (in percent)
(10) MMBTU Coal Displacement = (Item [6] * Item [9])
(11) Tons Of Coal Displaced Through Co-Firing = (Item [10]/ Item [8])

Step 2: Calculation of CO2 Reductions By Coal Displacement

(12) Carbon Content Of Coal (by weight, as received)
(13) Tons Of Carbon Reduction By Co-Firing = (Item [11] * Item [12])
(14) Molecular Weights Of Carbon To CO2 = 12 + 32 = 44
(15) CO2 Multiplier Of 3.67 = 44/12
(16) Tons Of CO2 Reduction = (Item [15] * Item [13])

Step 3: Calculation Of Sequestered CO2 At Plantation Site Through Tree Root System

(17) Percent Of Carbon Sequestered At Plantation Site In Non Harvested Root System
(18) BTU Content Per Pound Of Energy Crop (as received)
(19) MMBTU Content/Ton Of Harvested Energy Crop = (Item [18] * 2,000)/1,000,000
(20) Green Tons Of Energy Crop Fuel Harvested = (Item [10]/ Item [19])
(21) Carbon Content Of Energy Crop Fuel (by weight, as received)
(22) Sequestration Factor = (Item [17])/(1 minus Item [17])
(23) Tons Of Carbon Sequestered = (Item [20] * Item [22]) * Item [21]
(24) Tons Of CO2 Sequestered = (Item [23] * Item [15])

Step 4: Calculation Of Car Elimination Equivalent By Biomass Co-Firing Program

(25) Tons Of CO2 Reductions From Coal Displacement = Item [16]
(26) Tons Of CO2 Sequestered In Energy Crop Root System = Item [24]
(27) Total Tons Of CO2 From Energy Crop Program = (Item [25] + Item [26]
(28) Pounds Of CO2 Per Gallon Of Gasoline Combusted
(29) Miles Per Gallon Of Average Automobile
(30) Average Miles Traveled By Average Automobile
(31) Yearly Pounds Of CO2 From Average Auto = (Item [30] / Item [29]) * Item [28]
(32) Yearly Tons Of CO2 Emitted From Average Auto = (Item [31]/2000)
(33) Equivalent Autos Displaced By Energy Crop Program = (Item [27]/Item [32])

Step 1: Calculation Of Coal Displacement Through Biomass Co-Firing

(1) Capacity of Generating Station Unit (in KW) 365,000
(2) Capacity Factor Assumed For Unit (in percent) 90%
(3) Unit's Number Of Yearly Operating Hours 7,884
(4) Yearly KWH Produced At Unit 2,877,660,000
(5) Heat Rate Of Unit (BTUs required to produce 1 KWH) 10,000
(6) Total Input MMBTUs For Unit 28,776,600
(7) BTU Content Of Coal Per Pound (as received) 12,000
(8) MMBTU Content Of Coal Per Ton 24
(9) Biomass Co-Firing Ratio For Unit (in percent) 3.00%
(10) MMBTU Coal Displacement 863,298.00
(11) Tons Of Coal Displaced Through Co-Firing 35,971

Step 2: Calculation of CO2 Reductions By Coal Displacement

(12) Carbon Content Of Coal (by weight, as received) 70%
(13) Tons Of Carbon Reduction By Co-Firing 25,180
(14) Molecular Weights Of Carbon To CO2 12 (C) +32 (02) =44 (CO2)
(15) CO2 Multiplier 3.67
(16) Tons Of CO2 Reduction 92,325

Step 3: Calculation Of Sequestered CO2 At Plantation Site Through Tree Root System

(17) Carbon Sequestered At Plantation Site In Root System 50%
(18) BTU Content Of Energy Crop Per Pound (as received) 4,500
(19) MMBTU Content Of Harvested Energy Crop Per Ton 9
(20) Green Tons Of Energy Crop Fuel Harvested 95,922
(21) Carbon Content Of Energy Crop Fuel (by weight, as received) 24.91%
(22) Sequestration Factor 1.00
(23) Tons Of Carbon Sequestered 23,894
(24) Tons Of CO2 Sequestered 87,612

Step 4: Calculation Of Car Elimination Equivalent By Biomass Co-Firing Program

(25) Tons Of CO2 Reductions From Coal Displacement 92,325
(26) Tons Of CO2 Sequestered In Energy Crop Root System 87,612
(27) Total Tons Of CO2 Benefit From Energy Crop Program 179,937
(28) Pounds Of CO2 Per Gallon Of Gasoline Combusted 20
(29) Miles Per Gallon Of Average Automobile 20
(30) Average Miles Traveled By Average Automobile 11,000
(31) Yearly Pounds Of CO2 From Average Auto 11,000.00
(32) Yearly Tons Of CO2 Emitted From Average Auto 6
(33) Equivalent # Autos Displaced By Energy Crop Program 32,716

Registered Vehicles In Polk Co. 341,212

Polk County Population Demographics:

Total For Polk County 465,858
Unincorporated Polk County 289,399
Incorporated Cities In Polk County 176,459
City Of Lakeland 77,113
Lakeland Pop/Incorporated Polk Co. 44%
Estimated Lakeland Unincorporated 126,468

Estimated Lakeland Population:

Incorporated 77,113
Un-Incorporated 126,468
Total 203,581

Lakeland To Total Polk County 44%

Estimated Vehicles In Lakeland 149,110

Car Equivalent Removal From Biomass 32,716

Percentage Of Cars Removed To Total 22%