Carbon-negative emissions: Systemic impacts of biomass conversion

Abstract

This paper is a contribution to the ongoing debate on carbon-negative energy solutions. It deals with biomass conversion in dedicated biopower plants equipped with CCS (BECCS), or co-fired plants retrofitted with CCS in order to generate negative CO 2 -emissions. In this context, bioenergy refers to the use of biomass to generate electricity (i.e. biopower) in compliance with the needs of nations and regions without seasonal space heating demand. In this paper, direct-fired and co-fired systems will be addressed, combined mainly with post-combustion flue gas cleaning. The question is which CCS alternative should be preferred in order to obtain negative emissions: either building multiple smaller biopower units, or employing co-firing of biomass and coal in existing large coal power plants. Based on efficacy and the potential for mitigating greenhouse gas emissions as key indicators, some major differences between the alternatives are shown. In the event that a coal power plant equipped with CCS is readily available, more net electric energy (in MWh) can be provided from the feedstock of biomass than would be obtainable from a dedicated BECCS plant, although the amount of CO 2 captured and stored from the biomass (per tonne) will be essentially the same. Further casespecific cost-benefit analyses will be required to determine the feasibility of carbon-negative energy solutions. Although the study is carried out from the perspective of actual biomass sources as regards biomass composition and available technology (i.e. expected efficiency levels) using Indonesian agricultural residues, its main conclusion is fairly general.

Comparative potential of natural gas, coal and biomass fired power plant with post - combustion CO 2 capture and compression

“…At one end, the higher fuel flowrate requirement will disturb the boiler design, on the other end it will be an issue of logistics and supply of the sustainable biomass. A 800 MWe bio-power plant operating with full capacity will require 500 tons biomass per hour equivalent to 17 lorries per hour with 30 ton each (Hetland et al, 2016). However, the CO2 composition in the flue gas also increases by approximately 8 % with about 4 % decrease in the flue gas flow rate for the biomass case due to the higher O/C ratio in the biomass compared to the coal.…”

Striving towards the Deployment of Bio-Energy with Carbon Capture and Storage (BECCS): A Review of Research Priorities and Assessment Needs

“…There is a high uncertainty in cost estimates for BECCS as they are defined by many variables and assumptions coupled with the additional doubt of limited commercial experience of a full-scale CCS plant [26,27,29,31,32,42]. Given that there is an absence of constant and thorough assessment studies of current and expected cost of CCS, literature indicates that CCS technologies deficiency is the most important cost barrier for BECCS.…”

“…For large biomass-based substitute natural gas (BioSNG) production plants, Carbo et al, claim that the CO 2 avoidance cost amount to 62 €/ton CO 2 , under the assumption that these negative emissions are recognized in the emissions trading [47]. Finally, co-firing biomass with coal in bigger plants indicates a rather reduced incremental cost providing that CCS has already been included [42]. Table S2 in Supplementary Materials summarizes a collection of techno-economic assessment studies in literature, presenting key assumptions and findings, concerning various technology routes for the principal value chains of BECCS.…”

“…The introduction of BECCS to the storage stages of CCS does not cause any specific technical consequences, since the CO 2 stream produced by the capture process does not depend on the plant feedstock. For the case of biomass co-firing, developing the necessary infrastructure (i.e., specialized CO 2 pipelines routing to storage sites), will be constructed around existing large point sources [42]. Stored biogenic CO 2 offer the same value as stored fossil CO 2 and as a result, there should not be a difference between acceptable CO 2 emission reductions in the plant whether the stored CO 2 is fossil fuel derived or biogenic [49].…”

Environmental impact of an agro-waste based polygeneration without and with CO 2 storage: Life cycle assessment approach

“…He has shown a significant potential of net CO 2 removal from atmosphere through bioenergy with CCS. Hetland et al (2016) have studied different CCS alternatives and its impacts on biomass based energy systems to make it a net carbon negative solution. Luckow et al (2010) have investigated CCS for large scale biomass utilization in transport and energy sectors.…”