Role of Digestate and Biochar in Carbon-Negative Bioenergy

Role of Digestate and Biochar in Carbon-Negative Bioenergy

TitleRole of Digestate and Biochar in Carbon-Negative Bioenergy
Publication TypeJournal Article
Year of Publication2019
AuthorsHanna Breunig, Jahon Amirebrahimi, Sarah Josephine Smith, Corinne Scown
JournalEnvironmental Science & Technology
Date Published10/2019
ISSN0013-936X
Abstract

Digestate and biochar can be land applied to sequester carbon and improve net primary productivity, but the achievable scale is tied to expected growth in bioenergy production and land available for application. We use an attributional life-cycle assessment approach to estimate the greenhouse gas (GHG) emissions and carbon storage potential of biochar, digested solids, and composted digested solids generated from organic waste in California as a test case. Our scenarios characterize changes in organic waste production, bioenergy facility build-out, bioenergy byproduct quality, and soil response. Moderate to upper bound growth in the bioenergy sector with annual byproduct disposal over 100 years could provide a cumulative GHG offset of 50–400 MMTCO2 equiv, with an additional 80–300 MMTC sequestered in soils. This corresponds to net GHG mitigation over 100 years equivalent to 340–1500 MMTCO2 equiv (80–350% of California’s annual emissions). In most scenarios, there is sufficient working land to apply all available biochar and digestate, although land becomes a constraint if the soil’s rest time between applications increases from 5 to 15 years.

URLhttps://pubs.acs.org/doi/10.1021/acs.est.9b03763https://pubs.acs.org/doi/pdf/10.1021/acs.est.9b03763
DOI10.1021/acs.est.9b03763
Short TitleEnviron. Sci. Technol.