Return To 
Treepower Homepage
Prior Updates:

Return to Homepage


Co-firing test burn at TECO's Polk Power Station:   In December, whole eucalyptus trees were harvested and ground for biomass co-firing test burns (1 to 3% by generation) at Tampa Electric’s Polk Power Station. The Polk Power Station is an ~250 MW IGCC Coal Gasification Unit (an U.S. Department of Energy/EPRI sponsored clean coal project).

The first phase/series of the co-firing test burns were primarily directed to qualifying/grandfathering the Polk Power Station for the Internal Revenue Code Section 45 “Closed-loop Biomass and Wind Energy” Tax Credit. In the first phase/series of test burns (completed on December 31st), no obvious operational problems have been encountered, with the coal/biomass wet slurry passing through all screens.

Additional test burns (involving greater engineering analysis) are scheduled to be performed through April, 2002.

Qualifying the Polk Power Station for the Section 45 Tax Credit is a significant accomplishment, as economics for the future use of energy crops from our Energy Crop Plantation is tremendously enhanced. From an electric utility’s view, the economic value/revenue requirement benefit of the Section 45 Tax Credit is ~$2.75 per MMBTU.

Below are links to harvesting and grinding pictures of our eucalyptus "closed loop biomass" for the co-firing test burn at Tampa Electric's Polk Power Station.

First Grind
Final Grind
Hammers in Tub Grinder
Fuel from Tub Grinder to Trommel Screen
Screened Product from Trommel
Overs in back of Trommel
Loading whole trees into Tubgrinder
Whole logs into Tubgrinder
First pass screens used on Tubgrinder
Second pass screens used on Tubgrinder

Global Warming Research:   Collective/joint scientific “carbon sequestration” work with the University of Florida was begun at the Plantation, measuring “above ground” and “below ground” carbon sequestration of 13 month old eucalyptus trees (which averaged ~25 feet in height). This work was performed by: (1) excavating whole eucalyptus trees (including their root system) with a back-hoe and removing dirt from the root system; (2) weighing the entire tree; (3) cutting the tree at the stem, and weighing the tree’s “above ground” growth (i.e., the trunk, stems, leaves) and “below ground” (i.e., root system).

Initial weigh measurements were encouraging, with the “below ground” weight of the tree’s root system having >50% of the weight of the “above ground” growth. For example, whole trees weighed ~150 green pounds, with “below ground” weight at ~50 green pounds. According to Dr. Don Rockwood of the University of Florida, this 50% measurement of “below ground” carbon sequestration under-estimates the total “below ground” carbon sequestration, because smaller roots were left in the ground at excavation. The University of Florida will be performing scientific literature reviews on the carbon sequestration impact of the tree’s smaller root system.

Initial findings of this carbon sequestration research is very significant and encouraging, as it supports a belief that we have had for some time: “From a carbon sequestration/Global Warming Strategy perspective, co-firing energy crop biomass can accomplish more than any other form of renewable energy option.” The reason for this is that co-firing energy crop biomass in addition to being “carbon cycle neutral”, also creates a carbon sink (something that wind, solar, or geothermal can not do). Also, recognizing that energy crop trees (willows, cottonwoods, and eucalyptus) coppice/re-grow after harvesting, this carbon sink will be long-term in duration.

Additonal Tree Planting:   In December and January, the Plantation’s cottonwood clone bank was cut, producing ~35,000 cuttings. On January 23rd, we completed planting all of these cuttings at the Plantation. We now estimate that the Energy Crop Plantation is comprised of 50% eucalyptus trees, and 50% cottonwood trees.

Below are links to several pictures taken in the Fall of 2001 at the Plantation of 10 month old eucalyptus trees:

Close-up view of Tree bed.
Wide view of the sameTree beds.
Measurement of Trees by University of Florida.
Measurement of Trees by University of Florida.

We also completed disking and bedding an additional 20 acres using an experimental “micro-bed” bed design which entails much wider beds than previously developed.

Click for a larger picture

The purpose of this new bed design is to enhance drainage, and greater ease of harvesting using the Class Harvester.