A review of biopower and mitigation potential of competing pyrolysis methods

Pyrolysis can be used to produce renewable energy and offset greenhouse gas emissions. While the biopower potential of pyrolysis has been widely analyzed, agronomic and environmental benefits under competing pyrolysis modes have not been investigated and compared. This study reviews the properties and characteristics of major pyrolysis technologies including fast, intermediate, slow, gasification, and torrefaction, and then investigates and compares their biopower potential and the biochar-induced agronomic and environmental benefits so that the fundamental figures for future large-scale biopower development can be explored. The results indicate that (1) revenues from energy sale generally outweigh the agronomic and environmental benefits, but the extent depends on the commodity price and emission price; (2) if biochar is not used as an energy source, 10.58%-26.73% of biopower generation is decreased for fast pyrolysis and a 90%-97.44% decrease would occur for torrefaction; (3) biochar-induced agronomic benefits and emission offsets from torrefaction can greatly recover the loss of energy sales; and (4) with torrefaction the emission offset can be up to 2.82-3.19 tonnes carbon dioxide, on a per tonne biomass basis. We also discuss how biochar application might alleviate surface water eutrophication and groundwater pollution.

Automated summary

This study reviews and compares different pyrolysis technologies and their biopower potential as well as the agronomic and environmental benefits. The results suggest that revenue from energy sales generally outweighs the agronomic and environmental benefits, but the extent varies depending on commodity prices and emission prices. The study also finds that biochar can potentially offset the loss from energy sales and provide agronomic and environmental benefits.