|High & moderate results from the 2005 BTS and baseline & high-yield results from the Billion-Ton Update at a simulated farmgate or roadside price of $60 per dry ton. Source: DOE. Click to enlarge.|
The US Department of Energy released a new report—2011 U.S. Billion-Ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry, referred to as 2011 BT2—detailing US biomass feedstock potential for energy applications nationwide.
The new report basically supports the conclusion of the original 2005 Billion-Ton Study (2005 BTS, earlier post)—that the land resources of the US could produce a sustainable supply of biomass sufficient to displace 30% or more of the country’s present petroleum consumption—but expands on the original to include:
- A spatial, county-by-county inventory of potentially available primary feedstocks;
- Price and available quantities (e.g., supply curves) for the individual feedstocks; and
- A more rigorous treatment and modeling of resource sustainability.
The report is similar to the 2005 BTS in that it only provides estimates of biomass to roadside or the farmgate. The potential biomass inventory at a given spatial scale is biomass in the form and quality of the production system, which is identified in the report for a specific feedstock. It is important to understand that the estimates in the report do not represent the total cost or the actual available tonnage to the biorefinery. There are additional costs to preprocess, handle, and transport the biomass. There may be storage costs for specific feedstocks. Although the estimates do include losses to roadside, the estimates do not include losses due to continued handling, additional processing, storage, material degradation, and quality separation.
In effect, for example, more than one billion tons from estimates in the report would be required to have one billion tons ready to process at a biorefinery. The amount would be dependent on many variables in the continued supply chain and final conversion technology. In addition, the biomass is in varied forms and may not be directly comparable at a biorefinery in either cost or conversion efficiency. Determining such values is outside the scope of the report.—2011 BT2
The update evaluates two scenarios—baseline and high-yield. The baseline scenario essentially assumes a continuation of the US Department of Agriculture (USDA) 10-year forecast for the major food and forage crops, and it extends an additional 10 years to 2030. The average annual corn yield increase is assumed to be slightly more than 1% over the 20-year simulation period. The baseline also assumes a continuation in trends toward no-till and reduced cultivation. Energy crop yields assume an annual increase of 1%. The 1% change in annual yield in the baseline reflects learning or experience in planting energy crops and limited gains that can be had through breeding and selection of better varieties.
The high-yield scenario is more closely aligned to the assumptions in the 2005 BTS. In this scenario, higher corn yields and a much larger fraction of crop acres in reduced and no-till cultivation are assumed. Under the high-yield scenario, the projected increase in corn yield averages almost 2% annually over the 20-year simulation period. The energy crop productivity increases are modeled at three levels—2%, 3%, and 4% annually. These gains are due not only to experience in planting energy crops, but also to more aggressive implementation of breeding and selection programs.
While the overall results of this update are consistent with the 2005 BTS in terms of the magnitude of the resource potential, the 2011 BT2 finds that the forest residue biomass potential is somewhat less than in the 2005 BTS due to the removal of unused resources and the decline in pulpwood and sawlog markets. The crop residue potential is also less than the 2005 BTS due to the consideration of managing for soil carbon during crop residue removal and not allowing the removal of residue from conventionally tilled acres.
However, the energy crop potential is much greater owing to the inclusion of additional pasture land and explicit land-use change modeling. In the baseline, energy crops provide more than a third of the total biomass available and become even more significant in the high-yield scenario—providing nearly half of the available biomass.
The report’s findings demonstrate that increases in biomass-derived energy sources can be produced in a sustainable manner through the use of widely-accepted conservation practices, such as no-till farming and crop rotation. In fact, in some cases increased production may contribute to environmental improvements. For example, removing tree portions that are unfit for market in the forest industry can reduce forest fire risk, and planting energy crops on marginal lands can reduce soil erosion. The baseline scenario in the newly released report shows that biomass resources could be increased from a current 473 million dry tons annually to nearly 1.1 billion dry tons by 2030, under a conservative set of assumptions about future increases in crop yield.
As noted at the outset, the results of this updated assessment are consistent with the 2005 BTS in terms of overall magnitude. In fact, the scenario assumptions required to show a “billion-ton” resource (i.e., sufficient feedstock to potentially displace 30% or more of the country’s present petroleum consumption) are much more plausible. The forest resources take into account sawlog and pulpwood demands, and they factor in a more explicit accounting of resource sustainability. The agricultural resources now take into account soil organic matter in the assessment of crop residue potential and require less significant shifts of land into no-till cultivation. The energy crop potential is formally modeled and accounts for competition among various competing uses of the land.
Although the focus is more on the biomass supply and prices, the assumptions used to derive these estimates are tempered from the sustainability perspective. The update is not a quantitative environmental assessment or a comprehensive sustainability analysis, which means that the study does not evaluate a whole suite of sustainability criteria nor assess changes in the indicators as a function of production scenarios. It should also be stressed that bioenergy markets currently do not exist for the resource potential identified. The analysis and results are based on very limited data and, as such, require making numerous assumptions, and the results can be sensitive to these assumptions, especially with respect to production response to price.—2011 BT2
The online Bioenergy Knowledge Discovery Framework (Bioenergy KDF) allows for complete access to the 2011 BT2 data. Within the Bioenergy KDF, users can:
- explore county- and state-level data within the Data Map Interface;
- download selected crop data for multiple years in a spreadsheet; and
- access the complete Billion-Ton Update data files.
The 2011 Billion-Ton Update was produced in collaboration with the Energy Department’s Oak Ridge and Idaho National Laboratories, the US Department of Agriculture, The University of Tennessee, and other university and industry representatives.