Title: Life-cycle impact and exergy based resource use assessment of torrefied and non-torrefied briquette use for heat and electricity generation

Abstract

Forest residue biomass can be used as bioenergy feedstock, however, issues associated with its properties including low density and high moisture content constrains its valorization. Using mobile conversion technologies that can operate in remote areas and are capable of converting forest residues into high quality energy products can address the issues associated with its valorization for renewable energy production. This study evaluated environmental sustainability of using an integrated novel system of semi-mobile biomass conversion technologies (BCTs) to utilize low-value forest residue biomass as high value bioenergy products. A cradle-to-grave life cycle assessment (LCA) and resource use assessment on a unit-process level was conducted for two bio-products: nontorrefied briquettes (NTB) and torrefied briquettes (TOB). Their use for production of useful thermal energy in wood stoves for domestic heating and electricity at power plants were investigated along with their alternatives. The analyses were performed with SimaPro 8.5 using the DATASMART database. The impact assessment results showed a notable decrease in global warming (GW) impact when substituting fossil fuels with these two bio-products. Specifically, for domestic heating on an equivalent energy basis, a 50% substitution of propane with NTB and TOB showed GHG emission reductions of 46% and 41%, respectively. For electricity generation,more » 10% cofiring at coal power plant with NTB and TOB showed GHG emission reductions of 6% and 8%, respectively. For the TOB supply chain, a large portion of the GW impact of the came from the torrefaction process and followed by the drying process. This was due to the propane use in these processes. Comparative analysis showed that near-woods biomass conversion for TOB production instead of processing feedstock at an in-town facility with access to grid electricity found 48%–55% lower GW impact for both electricity and heat generation scenarios, respectively. Resourced footprint analysis showed that most exergy extraction from the natural environment came from the drying process for NTB supply chain. In the TOB product system, torrefaction was the major contributor.« less

Authors:

Alanya-Rosenbaum, Sevda ^[1]; Bergman, Richard D. ^[1]

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+ Show Author Affiliations

1. USDA Forest Service Forest Products Lab., Madison, WI (United States)

Publication Date:

Sat Jun 01 00:00:00 EDT 2019

Research Org.:

Humboldt State Univ., Arcata, CA (United States); Oak Ridge Associated Univ., Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Bioenergy Technologies Office; USDOE

OSTI Identifier:

1799204

Alternate Identifier(s):

OSTI ID: 1564318

Grant/Contract Number:  

EE0006297; AC05-06OR23100

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Cleaner Production

Additional Journal Information:

Journal Volume: 233; Journal ID: ISSN 0959-6526

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS; torrefaction; wood briquettes; life cycle assessment; resource use assessment; exergetic life cycle assessment; bioenergy