Negative Emissions Technologies and Reliable Sequestration A Research Agenda (2019) / Chapter Skim
Currently Skimming:
4 Bioenergy with Carbon Capture and Sequestration
4 Bioenergy with Carbon Capture and Sequestration
Pages 137-188
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 137... ...
. To put this in perspective, 1 Gt dry biomass is roughly equivalent to 1.4 Gt CO2 and 14 exajoules (EJ)
|
From page 138... ...
Compression, transportation, and sequestration are covered in Chapter 7.1 This chapter begins with a review of the various biomass energy–based carbon removal pathways and their commercial status. This is followed by an assessment of their removal and sequestration potential based primarily on biomass supply potential and process economics.
|
From page 139... ...
Bioenergy with Carbon Capture and Sequestration A B C FIGURE 4.1 Generic biomass energy-based carbon dioxide removal pathways: a) biomass-to-power with carbon capture and sequestration, b)
|
From page 140... ...
On forestland, annual biomass production exceeds current harvest by about 70 percent (Smith et al., 2007) or 204 Mt/y dry biomass.
|
From page 141... ...
A map of the distribution of biomass resources across the United States (Figure 4.3) shows that the east and west coasts and center of the United TABLE 4.2 Productivity of Selected Bioenergy Crops by Region (tonnes per hectare)
|
From page 142... ...
142 FIGURE 4.3 A map of solid biomass resources by county across the United States. SOURCE: NREL: https://www.nrel.gov/gis/images/biomass_2014/national_biomass_solid_total_2014-01.jpg.
|
From page 143... ...
and distance. Figure 4.5 presents an example of these estimates for dry biomass transport by truck, train, or sea freight (Beagle and Belmont, 2016)
|
From page 144... ...
show that truck transportation has significantly higher emissions per kilometer than train and sea freight. Biomass Conversion Figure 4.6 provides a detailed illustration of the many potential biomass-to-energy technologies, which are at varying technology readiness levels (TRLs)
|
From page 145... ...
. carbon-rich biochars that can be combusted, gasified, or sequestered as a soil amendment.2 Pyrolysis may proceed at high heating rates and short residence times to favor liquid yields (fast pyrolysis)
|
From page 146... ...
Table 4.3 presents estimated TRLs, carbon capture work, exergy efficiencies, levelized costs of electricity (LCOEs) , and carbon capture costs for the different coal power plant carbon capture approaches.
|
From page 147... ...
Carbon capture from fermentation processes, such as those used to produce ethanol, can utilize the same technology that is being developed for carbon capture in fossil fuel plants. CO2 is produced as a byproduct of the fermentation process itself, as well as from the power plant that supplies electricity and heat to the fermentation process.
|
From page 148... ...
. Biochar soil amendment has been proposed as a promising path for long-term carbon removal strategy; however, questions r emain about the long-term stability of biochar in soil environments.
|
From page 149... ...
Notably, the ADM emits approximately 5 Mt/y CO2, making the process net carbon positive because of CO2 emissions from the power plant. However, technoeconomic studies have shown that such processes can be carbon negative if CCS is applied across the entire chemical plant, including the fermenter and power generation unit.
|
From page 150... ...
10 Fermentation Butanol Green Biologics 8 Fermentation Ethanol (many) 10 Aqueous phase reforming Liquid hydrocarbons Virent/Shell 3 Organic Waste Aqueous phase reforming Liquid hydrocarbons Virent 3 Hydrothermal liquefaction Liquid hydrocarbons PNNL/Genifuels 4 Anaerobic digestion Methane (many)
|
From page 151... ...
BECCS CO2 flux potential for the United States. The economically feasible lower bound is 522 Mt/y CO2 and is based on the following assumptions: • No energy crops are utilized for BECCS.
|
From page 152... ...
152 Current 2017 2040 Use Source Technical Potential Economically Feasible Technical Potential Economically Feasible Biomass Biomass CO2 Flux Biomass CO2 Flux Biomass CO2 Flux Biomass CO2 Flux Agricultural Byproducts 130 154 269 125 218 219 382 195 339 Agricultural residues -- 106 185 94 164 171 298 161 280 Agricultural wastes -- 48 84 31 54 48 84 34 59 Energy Crops 0.087 503 875 -- -- 503 875 373 649 Switchgrass -- -- -- -- -- -- -- 146 254 Miscanthus -- -- -- -- -- -- -- 145 253 Biomass sorghum -- -- -- -- -- -- -- 17 30 Energy cane -- -- -- -- -- -- -- 0 0 Non-coppice -- -- -- -- -- -- -- 41 71 Coppice -- -- -- -- -- -- -- 24 41 Forestry 132 332 609 124 228 332 609 122 225 Logging residues -- 43 78 16 30 43 78 19 35 Whole-tree -- 143 263 64 117 143 263 55 102 Other wood wastes -- 146 268 44 82 146 268 48 88
|
From page 153... ...
TABLE 4.5 Continued Current 2017 2040 Use Source Technical Potential Economically Feasible Technical Potential Economically Feasible Biomass Biomass CO2 Flux Biomass CO2 Flux Biomass CO2 Flux Biomass CO2 Flux Organic Waste 36 259 240 259 240 309 286 309 286 Municipal solid waste 30 203 166 203 166 242 198 242 198 Construction and demolition -- 46 68 46 68 54 81 54 81 Sewage and wastewater 6 10 6 10 6 12 7 12 7 Total 298 1248 1993 508 686 1363 2152 999 1499 NOTES: Includes current levels of biomass utilization, lower- and upper-bound dry biomass potentials for different feedstock types, and associated CO2 flux potentials, assuming all biomass carbon content is captured and sequestered regardless of biomass conver sion path. SOURCES: DOE, 2016; EPA, 2016c; Rose et al., 2015; Seiple et al., 2017; USDA, 2014.
|
From page 154... ...
Technical potential is defined in this report as the total resource available, and availability in the years 2017 and 2040 were estimated from the agricultural residues available at $88 t dry biomass ($80 per short ton) , based on DOE (2016)
|
From page 155... ...
This value has been converted into annual production (Mt/y) by multiplying the acres of crops by the average dry biomass yield per acre (t/ acre)
|
From page 156... ...
Therefore, additional energy crops replace other types of current crops such as food crops. In 2040, 8.3 percent of agricultural lands are devoted to energy crops under the 1 percent annual yield increase and the $66/dry biomass scenario.
|
From page 157... ...
. Currently, the United States uses about 132 Mt annually of wood and wood waste for thermal and electric power and has the potential to nearly double this amount at a dry biomass price of 66 $/t based on economic modeling that excludes potential addi tional supplies from lands more than a 0.8 km (0.5 mi)
|
From page 158... ...
. From this, annual CO2e flux potentials of 166 Mt in 2017 and 198 Mt in 2040 are estimated using a municipal solid waste CO2 emissions per dry biomass factor of 0.82 t/t (EPA, 2014)
|
From page 159... ...
The U.S. upper-bound CO2 storage capacity based on biomass supply achievable with minimal impacts on current land and biomass use is 17 Gt CO2 by 2040, if annual CO2 sequestration is ramped linearly from 0 percent to 100 percent of the upper-bound CO2 flux potential (1,500 Mt/y CO2)
|
From page 160... ...
Fossil carbon flows consist of the CO2 and CH4 emissions from the combustion of the fossil fuels or materials needed by BECCS technologies. For example, transport of biomass by fossil fuel–powered vehicles or locomotives must be accounted for in estimating net carbon removal.
|
From page 161... ...
For example, natural gas can be used in biomass conversion processes, leading to CH4 emissions. Figure 4.8 shows an example of "carbon losses" associated with BECCS for switchgrass burned in an integrated gasification combined cycle power plant with carbon capture and sequestration (data taken from the literature)
|
From page 162... ...
These costs are summarized below, followed by specific estimates of carbon costs for CO2 generated and captured in a power plant and biochar produced by pyrolysis. Biomass Supply Costs Cost per ton of biomass supply is affected by many factors: productivity or yields per hectare, transportation (distance from roadside)
|
From page 163... ...
of biomass power plants. Low biomass power plant efficiency increases the already high cost of feedstocks ($50-80/t or $3-4/GJ dry biomass)
|
From page 164... ...
costs do not substantially differ between coal and biomass power plants, the cost of biomass-derived electricity can be estimated by modifying the current cost of fossil fuel–derived electricity to consider biomass feedstock and carbon capture costs. For a simple and direct comparison of fuels, the efficiencies of biomass and coal power plant are assumed to be the same, even though they are largely dependent on firing percentage and biomass pretreatment, such as torrefaction or densification.
|
From page 165... ...
Aside from physical constraints on biomass production, life cycle GHG emissions, and other potential radiative impacts, there are key uncertainties regarding indirect emissions, adverse effects on food security, impacts on biodiversity and land conservation, competition for water resources, and social equity and acceptance issues (Sanchez and Kammen, 2016)
|
From page 166... ...
. Nutrient removal associated with biomass harvesting (for energy crops as well as collecting agricultural and forest residues instead of leaving them on the ground as nutrients)
|
From page 167... ...
However, improvements are still needed to include impacts on biodiversity, ecosystem services, and water resources. Societal Impacts Energy crops compete with food crops for available agricultural land.
|
From page 168... ...
These definitions assume commercialscale biomass-to-power or fuel plants have a dry biomass capacity of about 1,000 t/d, roughly equivalent to a fuel heating value of 220 MW at 19 GJ/t dry biomass.
|
From page 169... ...
Bench-scale prototype is environment defined as less than 1 percent of final scale (e.g., complete technology has undergone bench-scale testing using actual dry biomass feed stock of 0.01-1.0 t/d)
|
From page 170... ...
The scale of this technology expected conditions is expected to be 50-250 t/d dry biomass capacity plant (e.g., complete and fully integrated technology has undergone full-scale demonstration testing using dry biomass feedstock at a scale equivalent to approximately 50 t/d dry biomass or greater)
|
From page 171... ...
Crosscutting Activities 1.1 Regional Life Cycle Assessments and Integrated Assessment Modeling Model Development 1-3 1.5-5.0 10 $0.5-1.0MM per project, 3-5 projects/y, 1-3 y projects Secondary Impacts 1-3 0.6-2.5 10 $0.5-1.0MM per project, 2-3 projects/y, 1-3 y projects Spatial and Temporal 1-3 0.6-2.5 10 $0.5-1.0MM per project, 2-3 Resolution projects/y, 1-3 y projects Food Security Impacts 1-3 0.5-2.0 10 $0.5-1.0MM per project, 2-3 projects/y, 1-3 y projects Technology Assessments 1-3 0.5-2.0 10 $0.5-1.0MM per project, 2-3 projects/y, 1-3 y projects 2. Biomass-to-Power with Carbon Capture 2.1 Biomass Supply and Logistics Pretreatment Technology 1-3 1.2-3.5 5 $0.2-0.5MM per project, 6-7 projects/y, 1-2 y projects Feedstock Logistics 1-3 0.8-2.5 5 $0.2-0.5MM per project, 4-5 Research projects/y, 1-2 y projects Bench-Scale Prototypes 4-5 2.0-5.0 5 $0.5-1.0MM per project, bench-scale <1 t/d biomass, 4-5 projects/y, 1-2 y projects Feasibility Study (Stage- 5-6 0.2-0.3 5 Rule-of-thumb: 1% est.
|
From page 172... ...
at 1,000-2,000 t/d, $100-120/t, 5 y, $180-440MM per project Depot-Level 7-9 37-88 5 Budget to be revised from Demonstration engineering study, $180-440MM per project, 5-y projects 2.2 High Efficiency Biomass Power Efficient Biomass Power 1-3 1.0-7.0 10 $0.2-1.0MM per project, 5-7 Concepts projects/y, 1-3 y project Bench-Scale Prototypes 4-5 3.0-10 10 $1-2MM per project, <1 t/d biomass, 3-5 projects/y, 1-3 y projects Feasibility Study (Stage- 5-6 1.0-3.0 10 Rule-of-thumb: 1% est. plant Gate)
|
From page 173... ...
Biomass-to-Fuel with Biochar Biochar Soil Amendments 1-3 0.4-3.0 10 $0.2-1.0MM per project, 2-3 projects/y, 1-3 y projects Carbon Negative Pathways 1-3 1.0-7.0 10 $0.2-1.0MM per project, 5-7 projects/y, 1-3 y projects Bench-Scale Prototypes 4-5 3.0-10 10 $1-2MM per project, <1 t/d biomass, 3-5 projects/y, 1-3 y projects Feasibility Study (Stage-Gate) 5-6 1.0-3.0 10 Rule-of-thumb: 1% est.
|
From page 174... ...
Other carbon dioxide removal approaches such as direct air capture, biochar, or soil carbon sequestration should be incorporated to the models to account for the full portfolio of potential solutions and to improve our understanding of how BECCS and other land use–based mitigation interact in different economic and political contexts (Popp et al., 2014)
|
From page 175... ...
Research is needed to improve the estimation of critical parameters such as biomass yields in IAMs and to include other carbon dioxide removal approaches to develop future scenarios that account for the full portfolio of potential climate mitigation techniques. Secondary Impacts The field requires improved IAMs of the impact of bioenergy technology deployment on ecosystem services, biodiversity, albedo changes, and water resources.
|
From page 176... ...
Food Security Impacts The objective of this activity is to improve understanding of the impact of BECCS technology deployment on food prices and food security. The large-scale implementation of land-based carbon dioxide removal approaches might lead to food price increases through competition for land, as has been shown in some studies (Kreidenweis et al., 2016; Smith et al., 2013)
|
From page 177... ...
In the long-term, high-efficiency biomass power generation will be essential to the sustainability, scalability, and cost-effectiveness of carbon negative biomass-to-power. Task 2.1 Biomass Supply and Logistics The development of a robust biomass feedstock supply and effective supply chain is a key to replacing today's coal power plants with biomass power plants.
|
From page 178... ...
Research is needed to evaluate and develop biomass densification, pretreatment, and formation techniques using a variety of biomass feedstocks (agricultural byproducts, energy crops, wood, and organic waste) into a product that is compatible with coal-fired power plants.
|
From page 179... ...
The DOE Office of Fossil Energy's National Energy Technology Laboratory (NETL) has the most relevant expertise and experience for managing this program because of its long history of developing coal power plant technology, advance power generation, and carbon capture technology -- even though biomass power does not exactly fall within the priorities of Fossil Energy.
|
From page 180... ...
The carbon negative biomass-to-fuel with biochar processes can be advanced by determining the value of co-produced biochar and by optimizing existing processes or developing new pathways that maximize carbon removal. To this end, research in two main areas is proposed.
|
From page 181... ...
Research is needed to optimize existing biomass-to-fuel processes and to develop new pathways for net carbon negative emissions. Emphasis should be on robust processes and that can utilize a multitude of biomass feedstocks to maximize their long-term commercialization potential as well as enabling subsystem technologies that reduce the overall costs of carbon negative biomass-to-fuel processes.
|
From page 182... ...
, is needed to promote biomass markets, and extension and outreach may be needed to Bioenergy with Carbon Capture and Sequestrationcrops and practices. encourage landowners to adjust 21 Implementation of the Research Agenda Funding Implementation of the Research Agenda FundingScale of Funding Scale of Funding agenda budgets for prototype development were estimated assuming a The research 1000 t/d dry biomass commercial-scale plant has a capital cost of about $100 million, The research50 percent efficient power plant corresponds to estimated assuming a $900/t/d dry which for a agenda budgets for prototype development were capital cost of about 1000 biomass kW electrical capacity -- on a capital cost cost of naturalmillion, which for a 50 percent efficient commercial-scale plant has par with the of about $100 gas combined cycle power power plant corresponds to capital cost offor economies ofelectrical capacity -- on par with the cost of plants.
|
From page 183... ...
Bioenergy with Carbon Capture and Sequestration TABLE 4.9 Estimated Bench, Pilot, Demonstration-Scale Plant Costs, Dry Biomass C apacities, and Technology Readiness Levels Plant Scale Bench Pilot Demonstration Commercial Technology Readiness Level 4-5 6 7-9 10+ Dry Biomass Capacity, t·d-1 1 10 100 1000 Fuel Power, MW 0.2 2.2 22 220 Capital Cost, $MM 1 5 22 100 Cost per Capacity, $MM/(t·d-1) 1 0.5 0.2 0.1 FIGURE 4.10 Illustrative research agenda budgets per year showing possible sequencing for biomass-topower with carbon capture (top)
|
From page 184... ...
, c0 is the reference unit capacity, and α is the scaling factor of 2/3; an order-of-magnitude cost was estimated for bench, pilot, and demonstration-scale prototypes, Table 4.9. Sequencing of Funding The research agenda budgets for development of bioenergy with carbon capture technology are intended to be staggered over a period of 15 years.
|
From page 185... ...
By contrast, CO2 emissions from the combustion of fossil fuels is straightforward and easily accounted for using existing reporting on fossil fuel extraction, imports, and sales. For biomass energy carbon removal approaches, carbon accounting is particularly challenging because the amount of net carbon removal largely depends on the specific pathway chosen (i.e., production, 4 See https://www.netl.doe.gov/research/coal/carbon-capture/carbon-capture-program (accessed January 28, 2019)
|
From page 186... ...
for energy crops. In the United States, assuming 1 billion tons of biomass is needed, a sufficient supply could be achieved with energy crops, forest biomass, organic waste, and agricultural residues, but the associated GHG emissions and environmental impacts remain unclear.
|
From page 187... ...
Another research aim is to optimize existing biomass-to-fuel processes for carbon removal and investigate completely new carbon negative pathways. To accelerate technology deployment, the research agenda calls for the development of bench, pilot, and demonstration-scale prototypes for the most promising carbon negative approaches, scaling the dry biomass capacity from roughly 1 t/d bench-scale to 100 t/d demonstration-scale.
|
From page 188... ...
Given that lignin represents about 30 percent by mass and 40 percent by energy content of all biomass, bioengineering pathways to break down and convert lignin to liquid fuels is specifically recommended. More broadly, only basic and applied research on carbon negative pathways is recommended for biological biomass conversion until a breakthrough is made in lignin valorization.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.