Energy & Technology
- Plants, soils, and organic matter contain nearly three times the amount of carbon currently stored in the atmosphere.
- Biosequestration has the potential to make a significant impact by absorbing annual human-caused carbon emissions through changes in land management practices.
- Increasing rates of biosequestration can support other environmental outcomes such as improved wildlife habitat, water quality, reduced run-off, and better recreational opportunities.
- Biosequestration may someday be profitable for private landowners who adopt certain land management practices and participate in a carbon market.
- Biosequestration decreases atmospheric CO2 until the carbon that is in the plant, soil, or end product is released back to the atmosphere.
Addressing the risk of dangerous climate change requires the combined efforts of both greenhouse gas (GHG) emission reductions and sequestration. The purpose of this document is to discuss briefly the technology of biotic sequestration (or "biosequestration"): the absorption and storage of carbon in organic matter.
Biosequestration refers to a category of biological processes that absorb carbon dioxide (CO2), the primary GHG, from the atmosphere and contain it in living organic matter, soil, or aquatic ecosystems. The opportunities for expanding biosequestration by changing management and land-use practices are generating debate among landowners, policymakers, and the media. Other avenues of enhancing natural carbon capturing processes may exist, but more study is needed to determine their potential for climate change mitigation.1
Biosequestration occurs naturally in the global carbon cycle (Figure 1). It is estimated that the atmosphere contains about 2,750 billion metric tons of CO2 (2,750 gigatons of carbon, GtCO2).2 Terrestrial vegetation, soils, and organic matter contain the equivalent of up to 8,030 GtCO2 or just under 3 times the amount contained in the atmosphere.3 It is estimated that in the 1990s, 5.8 GtCO2 per year were released into the atmosphere as a result of global land-use change and deforestation, though some forests expanded in temperate and boreal zones.4 For comparison, the United States emitted on average about 7 GtCO2 per year from land-use change between 2003 and 2007, or about 0.25 percent of the entire atmospheric CO2 each year.5 Enhancing the capacity for carbon storage or the rate that CO2 is biosequestered is an important strategy for mitigating climate change.
|Figure 1: The Global Carbon Cycle (in GtC)|
Technology, Environmental Benefits, and Emission Reduction Potential
Although biosequestration occurs naturally every day, actions preventing the loss of carbon stocks and increasing the rate of biosequestration can also be intentional. Some biosequestration methods have a greater carbon impact than others depending on the rate of carbon absorption and storage. For example, fast-growing tree species can be used in afforestation and reach sequestration rates of 5 metric tons CO2 (tCO2) per acre per year, while planting prairie grass in place of an annual agricultural crop could sequester an additional 1.5 tCO2 per acre per year depending on local climate and weather variability.6,7 A range of carbon sequestration rates from selected land-use practices is presented below (Table 1).8,9,10
Although carbon stocks in forests, agricultural lands, and wetlands have been reduced over time, and thus offer opportunities for carbon storage through restoration, they are not pools where unlimited amounts of CO2 can be stored. All biosequestration practices will reach a saturation point at which a new carbon equilibrium is reached.11
Like other GHG mitigation options, different quantities of biosequestration are achievable at different costs. Under the cap-and-trade program passed by the U.S. House of Representatives in 2009 (H.R.2454), domestic biosequestration (in the form of cap-and-trade offsets) was projected to provide between 292 and 676 million metric tCO2 of annual abatement in the year 2030. (For comparison, GHG emissions from sources covered under the cap were projected to be between 926 and 2586 million metric tCO2 below the "business-as-usual" projected emissions level in 2030.)12,13
|Table 1: Estimated Sequestration Potential by Practice in the United States (Metric Tons CO2 per Acre per Year): Selected Land Use and Production Practice Changes|
Biosequestration is a biogeochemical process, meaning that it occurs at the interface of living organisms and geological processes. For example, when CO2 from the atmosphere is taken in by a plant, newly formed molecules (usually sugars and other carbohydrates that contain the carbon) end up in all parts of the plant including the leaves, stems and roots (Figure 2). The carbon is considered sequestered until the organic matter decomposes or burns, at which point it returns to the atmosphere as CO2. After plants die and fall to the ground, some carbon is incorporated into the soil when roots or dead leaves become soil organic carbon (SOC). Land that has been afforested or planted in perennial crops may have the greatest potential for accumulating soil organic carbon.14
|Figure 2: Biosequestration at the Level of an Organism|
Not only may biosequestration help to mitigate climate change, but certain methods can also contribute other significant environmental benefits. For example, changes in forest management can provide benefits beyond storing carbon by reducing soil-erosion and run-off, reducing flooding, protecting fisheries, and enhancing wildlife habitat and biodiversity.15 Similar benefits could also accompany changes in the management of farmlands and rangelands, and the restoration of wetlands. Environmental benefits will not happen automatically in biosequestration projects but must be planned for if they are preferred.
The cost of biosequestration varies widely depending on the practice, the land-owner, and the location of the biosequestration project. Much agricultural and forested land in the United States is privately-owned. Biosequestration would likely have to be financially favorable compared with current management practices for land managers to consider a change.16 Therefore, increasing carbon sequestration on these lands probably requires some form of payment for the carbon service provided or the practice implemented. Carbon markets and other pricing policies are discussed in more detail below.
A review of 11 cost analyses focusing on U.S.-based forest sequestration programs that varied broadly in their estimated costs of carbon sequestration estimated that 300 million metric tons CO2-equivalent (tCO2e) of annual carbon sequestration could occur in forest ecosystems at a cost of $7.50 to $22.50 per tCO2e.17 A separate study of the costs of sequestering carbon on agricultural land yielded an estimate of up to 77 million tCO2e per year when carbon is priced in a similar range (~$13 per tCO2/acre/year).18 For comparison, total U.S. GHG emissions are about 7 billion metric tons of CO2e per year. The estimate of agricultural carbon sequestration is about 1 percent of the total annual U.S. GHG emissions. The aforementioned estimate of forest biosequestration projects is equivalent to about 4 percent of annual U.S. GHG emissions.
Studies of global biosequestration estimate that a carbon price of $23.54 could induce 744 million tCO2e per year of forest carbon sequestration by the year 2010.19 Again, total annual biosequestration would vary considerably depending on the region, ranging from 20 million tCO2e in Oceania to 280 million tCO2e per year in North America. The difference between the North American estimate and the U.S. estimate above illustrates that biosequestration estimates vary.
Carbon prices and markets to trade carbon will help considerably in supporting biosequestration practices. However, reputable markets will require measurement and verification that also add to the cost of these practices. It is also reasonable to expect that credit aggregators will act as facilitators between biosequestration project owners and the credit exchanges. This facilitation will also come with a cost. In the end, transaction costs such as these could be significant.20
A global system of recognized practices and credits for biosequestration does not currently exist. Policies and programs that are effective in increasing the adoption of biosequestration practices are fragmentary, especially in the United States.
The Kyoto Protocol – an international agreement governing GHG emissions – comes nearest to establishing a global system of biosequestration initiatives.21 Nations that are party to the Kyoto Protocol have agreed to country-specific GHG emissions reductions by 2012. Articles 3.3 and 3.4 of the protocol outline the ways in which nations can account for afforestation, reforestation, deforestation, and certain other land-use activities in their particular emission reduction goals. Countries are also allowed to reach part of their goal through investments in flexible GHG offsets guided by United Nations programs called the Clean Development Mechanism and Joint Implementation (CDM/JI).22 Biosequestration projects in CDM/JI are mostly afforestation projects sponsored by countries with carbon reduction targets in countries without reduction targets (typically, countries that are considered non-industrialized).
The European Union Emission Trading Scheme (EU ETS) is currently the largest mandatory carbon market in the world. However, offsets from biosequestration are not currently allowed in the EU ETS.23
Current U.S. drivers of biosequestration include voluntary offset programs like the Chicago Climate Exchange and the Climate Action Reserve, and regional GHG reduction programs like the Regional Greenhouse Gas Initiative (RGGI). Each of these programs defines how biosequestration projects can be measured in slightly different ways.24,25,26
It bears repeating that biosequestration practices depend on living systems that are not easily quantified in a direct way. This lack of established measurement protocols leads to uncertainties in actual carbon sequestered compounded by the uncertain storage time. Measurement is made even more challenging by seasonal variations in weather and precipitation, differences between plant species, and the variation in the quality of soils and lands where these practices could be used. Land managers know a lot about growing trees, perennial crops, managing rangeland for carbon, and even restoring wetlands, but those practices need better measuring techniques for their legitimacy to be widely accepted.
Obstacles to Further Development or Deployment
A number of challenges have emerged to the further development of biosequestration practices:27
- Lack of a price on GHG emissions
Currently, in the United States there is no comprehensive policy that values biosequestration. A policy, such as cap and trade (see Climate Change 101: Cap and Trade), that puts a price on GHG emissions and limits total emissions, could create a market for offsets from biosequestration.
- Carbon storage easily reversed and re-emitted to the atmosphere
Living systems are subject to natural variation including unforeseeable climatic, weather, and destructive events. If a biosequestration project is destroyed by wildfire or heavy storms, the carbon stored there will be rapidly released back to the atmosphere. Without clear ownership or contracts, the liability of restoring this carbon remains uncertain.
- Establishing "baseline" measurements
The significance of choosing a baseline year against which sequestered emissions will be measured and compared is often understated or overlooked. A baseline will determine how much carbon is sequestered or emitted from a particular practice or project compared to a given year, usually in the past. This often serves as an anchor to measure how well a certain practice is performing relative to a certain emission reduction effort.
- Measurement of real carbon sequestered
Measurement, monitoring, and verification have been mentioned above. Biosequestration is difficult to quantify quickly or cheaply due to the constant flow of CO2 into and out of these living systems. This makes trading metric tons of biosequestered carbon difficult without accurate tracking and certification.
- Transaction costs
Transaction costs are projected to be significant in carbon markets. For example, in the voluntary Chicago Climate Exchange (CCX), some aggregators already in operation charge 8-10 percent of the value of the carbon credits in addition to a common listing fee of $0.20 per metric ton. Costs to implement biosequestration practices will need to be minimized in order to most cost-effectively utilize biosequestration for GHG abatement.
- Property rights and decision-making
Land-use decisions are often complicated by government regulation and property-owner preferences and traditions. Any successful implementation of biosequestration practices will depend on the legitimate involvement of all stakeholders including landowners, policymakers, community members, private enterprise, and other affected parties.
Each of these challenges must be addressed appropriately for biosequestration to be implemented at a climatically significant scale.28
Policy Options to Help Promote Biosequestration
There are two primary policy strategies that could help promote biosequestration:29
- Practice-based incentives
Practice-based incentive programs are already common for farmers using conservation practices on their land. Some U.S. farm programs - for example the Conservation Reserve Program - explicitly recognize carbon sequestration as a benefit. Farmers implementing a land-use change for the primary purpose of increasing biosequestration on their land could be supported through cost-sharing of the practice establishment, for example. Supporting a practice but not performance leaves little room for rewarding actual carbon benefits aside from the shift in management.
- Performance-based incentives
Performance-based incentives reward actions that have higher rates of carbon sequestration.30 Performance-based incentive programs are compatible with a carbon market, which would be created by a cap-and-trade program (see Climate Change 101: Cap and Trade).
Many cap-and-trade proposals allow biosequestration projects to generate offset credits that can be used by covered entities to comply with the emission limit. Offsets from biosequestration can be thought of as reducing carbon emissions in place of actions taken by a covered entity to reduce emissions directly at the source through energy efficiency measures and other activities. For example, an electric generator faced with a need to reduce its emissions could do so via a combination of increasing its non-emitting generation (e.g., from nuclear, wind, or solar power), decreasing its traditional fossil fueled generation, and paying a forest landowner to increase biosequestration on her land. If biosequestration offsets are adequately verified, then offsets could be a cost-effective way of reducing net GHG emissions over time.
Other helpful policies that would foster higher biosequestration penetration in performance-based markets would include risk reduction strategies for uncontrollable events (wildfires and weather), transaction cost reduction, and increased certainty in carbon measurement.
Related Business Environmental Leadership Council (BELC) Company Activities
Related C2ES Resources
Agriculture's Role in Greenhouse Gas Mitigation, 2006
Biological Sequestration through Greenhouse Gas Offsets: Identifying the Challenges and Evaluating Potential Solutions, April 2009 Workshop co-sponsored by the Center.
Briefing on Domestic Offsets in a Greenhouse Gas (GHG) Cap-and-Trade System, 6 March 2009.
The Cost of U.S. Forest-Based Carbon Sequestration, 2005.
Greenhouse Gas Offsets in a Domestic Cap-and-Trade Program, Congressional Policy Brief, 2008.
Issue Overview: Role of Offsets in Cap and Trade, U.S. Climate Action Partnership (USCAP), 2009.
Offset Quality Initiative (OQI).
Further Reading/Additional Resources
Baker JM, Ochsner TE, Venter RT, Griffis TJ (2007). Tillage and soil carbon- what do we really know? Agriculture, Ecosystems and Environment 118: 1–5.
Birdsey R (2004). Data Gaps for Monitoring Forest Carbon in the United States: An Inventory Perspective. Environmental Management 33. Supplement 1: S1–S8.
United States Department of Energy (2008). Carbon Cycling and Biosequestration Workshop Report: Publication No. DOE/SC-108.
European Union Memo (2008). Questions and answers on deforestation and forest degradation. Reference: MEMO/08/632.
Hansen EA (1993). Soil carbon sequestration beneath hybrid poplar plantations in the north central United States. Biomass and Bioenergy 5: 431-436.
Johnson R (2009). Climate Change: The Role of the U.S. Agriculture Sector and Congressional Action. Congressional Research Service. Publication No. RL33898.
Johnson R, Gorte RW (2009). Estimates of Carbon Mitigation Potential from Agricultural and Forestry Activities. Congressional Research Service. Publication No. R40236.
Johnson KS, Karl DM (2002). Is Ocean Fertilization Credible and Creditable? Science 296: 467-468.
Kopp RJ, Pizer WA et al. (2007). Assessing US Climate Policy Options. Report briefings on climate policy options including Biosequestration, among many others.
Lal R (2008). Sequestration of atmospheric CO2 in global carbon pools. Energy & Environmental Science 1: 86–100.
Lewandroski J, Peters M, et al. (2004). Economics of Sequestering Carbon in the U.S. Agricultural Sector. Technical Bulletin No. (TB-1909).
McLauchlan KK, Hobbie SE, Post WM (2006). Conversion of agriculture to grassland builds soil organic matter on decadal timescales. Ecological Applications 16: 143-153.
Murray BC, Sohngen B, et al. (2005). Greenhouse Gas Mitigation Potential in U.S. Forestry and Agriculture. Publication No. EPA 430-R-05-006.
Nabuurs GJ, Masera O, et al. (2007). Chapter 9: Forestry. Climate Change 2007: Mitigation. Assessment Report 4 of the IPCC. Cambridge University Press.
Parrotta JA (2002). Restoration and management of degraded tropical forest landscapes. In Modern Trends in Applied Terrestrial Ecology. R.S. Ambasht and N.K. Ambasht (eds.), Kluwer Academic/Plenum Press, New York, pp. 135-148 (Chapter 7).
Parry IWH, Pizer W (2007). Backgrounder: Emissions Trading versus CO2 Taxes versus Standards. Resources for the Future.
Schlamadinger B, Johns T et al. (2007). Options for including land use in a climate agreement post-2012: improving the Kyoto Protocol approach. Environmental Science and Policy 10: 295-305.
Sedjo RA, Amano M (2006). The Role of Forest Sinks in a Post-Kyoto World. Resources for the Future.
Shrestha R, Lal R (2008). Offsetting carbon dioxide emissions through minesoil reclamation. Encyclopedia of Earth.
Smith P, Martino D, et al. (2007). Chapter 8: Agriculture. Climate Change 2007: Mitigation. Assessment Report 4 of the IPCC. Cambridge University Press.
United States Department of State (2000). United States Submission on Land-Use, Land-Use Change, and Forestry to the Kyoto Conference of Parties. Accessed August 1, 2009.
Wise, A (2008). The US Carbon Market. Renewable Energy World News.
NETL Regional Carbon Sequestration Partnerships
DOE Terrestrial Sequestration Research
1 See, for example, Johnson KS, Karl DM, "Is Ocean Fertilization Credible and Creditable?" Science 296: 467-468, 2002.
2 The difference between tons of carbon (tC) and tons of carbon dioxide (tCO2) is often confused. It is confusing because CO2 is 3.67 times more massive than C alone due to the added molecular weight of oxygen (O2). Therefore 1 tC is equivalent to 3.67 tCO2.
3 Stavins R, Richards K, The Cost of U.S. Forest-Based Carbon Sequestration, 2005
4 Nabuurs GJ, Masera O, et al., "Chapter 9: Forestry" in Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007.
5 Johnson R. Climate Change: The Role of the U.S. Agriculture Sector and Congressional Action, Congressional Research Service, 2009. Report RL33898.
6 Hansen EA, "Soil Carbon Sequestration beneath Hybrid Poplar Plantations in the North Central United States," Biomass and Bioenergy 5: 431-436, 1993.
7 McLauchlan KK, Hobbie SE, Post WM, "Conversion of Agriculture to Grassland Builds Soil Organic Matter on Decadal Timescales," Ecological Applications 16: 143-153, 2006.
8 Johnson R, Gorte RW, Estimates of Carbon Mitigation Potential from Agricultural and Forestry Activities, Congressional Research Service, 2009. Report R40236.
9 Lewandroski J, Peters M, et al., Economics of Sequestering Carbon in the U.S. Agricultural Sector, U.S. Department of Agriculture Technical Bulletin Number1909, 2004.
10 Murray BC, Sohngen B, et al., Greenhouse Gas Mitigation Potential in U.S. Forestry and Agriculture, U.S. Environmental Protection Agency (EPA) Publication No. 430-R-05-006, 2005.
11 U.S. EPA , "Representative Carbon Sequestration Rates and Saturation Periods for Key Agricultural & Forestry Practices," 2006.
12 Energy Information Administration (EIA), Energy Market and Economic Impacts of H.R. 2454, the American Clean Energy and Security Act of 2009, 2009. See Table ES-1.
13 For more information on H.R.2454, the American Climate and Energy Security Act of 2009 (ACESA), see /acesa.
14 Degryze S, Six J et al., "Soil Organic Carbon Pool Changes Following Land-Use Conversions," Global Change Biology 10: 1120–1132, 2004.
15 Parrotta JA, "Restoration and Management of Degraded Tropical Forest Landscapes," in Modern Trends in Applied Terrestrial Ecology, R.S. Ambasht and N.K. Ambasht (eds.), Kluwer Academic/Plenum Press, New York, 2002.
16 Richards K, Sampson RN, and Brown S, Agricultural & Forestlands: U.S. Carbon Policy Strategies, 2006.
17 Stavins, 2005.
18 Paustian K and Antle JM, Agriculture's Role in Greenhouse Gas Mitigation, 2006.
19 Sohngen B and Mendelsohn R, Optimal Forest Carbon Sequestration, Department of Agricultural, Environmental, and Development Economics, Ohio State University. Working Paper AEDE-WP-0009-01, 2001.
20 Nabuurs et al., 2007.
21 Schlamadinger B, Johns T et al., "Options for Including Land Use in a Climate Agreement Post-2012: Improving the Kyoto Protocol Approach," Environmental Science and Policy 10: 295-305, 2007.
23 European Union, "Questions and Answers on Deforestation and Forest Degradation," MEMO/08/632, 2008.
24 Chicago Climate Exchange, "CCX Exchange Offsets and Exchange Early Action Credits" in CCX Confidential, 2004.
25 California Climate Action Registry, Forest Project Protocol, 2009.
26 Regional Greenhouse Gas Initiative (RGGI), "Offset Project Categories: Afforestation."
27 Smith P, Martino D, et al., "Chapter 8: Agriculture," in Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007.
29 Richards et al., 2006.
It will probably take some time to fully understand what went wrong in the Deepwater Horizon oil spill, and what ought to be done to make sure it doesn’t happen again. But at least one thing is already perfectly clear: recent technological advances in extracting oil in deep water offshore have been dramatic, whereas unfortunately the same cannot be said for technological advances in spill prevention and cleanup techniques.
Why is this the case? Innovation is complicated, but we do know something about it. In the private sector, the profit motive is a primary driver of innovation. Because of the world’s seemingly insatiable demand for petroleum products (mainly gasoline and diesel), oil companies have invested hundreds of millions of dollars in offshore drilling technology (just one company, GE Oil & Gas, reported offshore oil and gas drilling-related R&D spending of $150 million from 2009-2011) in order to reap tens of billions in proceeds from fuel sales (for fiscal year 2009, MMS reported oil production worth $20.2 billion from the Gulf of Mexico federal outer continental shelf). According to the U.S. Energy Information Administration (EIA), oil production from federal offshore areas accounted for 29 percent of total domestic oil production in 2009. In 2009, ultra-deepwater offshore drilling (drilling in more than 5,000 feet of water) accounted for about a third of total federal offshore oil production, and ultra-deepwater production tripled from 2005 to 2009. Until recently there has been no comparable incentive for spill prevention and cleanup techniques: the pre-Deepwater Horizon spill record had been excellent, lulling both regulators and oil companies into complacency.
The free market by itself cannot motivate investment in spill prevention and cleanup technology, because spills themselves yield public damage, not private profits. Our government, on behalf of the public interest, could have put rules in place that would have motivated the private sector to make such investments – such as requiring oil companies to actually demonstrate that spill prevention technology works as a condition for obtaining drilling rights.
We have an analogous situation with respect to energy security and climate change. The free market by itself is driving innovation, but in the wrong things: in energy investments that are warming the climate and making us ever more dependent on foreign oil. We need our government to intervene on behalf of the public interest to motivate private investment and innovation in clean energy, through comprehensive energy and climate legislation.
The catastrophe in the Gulf is still unfolding, and will ultimately provide many lessons relevant to our energy and environmental future. But one lesson we can take to heart and act on right away is that there is a profound public interest in spurring innovation in clean and safe energy and that the private market on its own will not adequately provide it. It is our job as the public to demand it, and it is our government’s job to use all the tools at its disposal – from regulations to incentives to penalties – to make it happen.
Judi Greenwald is Vice President for Innovative Solutions
Through a recently signed Presidential Memorandum, Barack Obama is continuing the push to regulate greenhouse gas emissions from the transportation sector using its authorities under the Clean Air Act (CAA) and the Energy Independence and Security Act of 2007 (EISA). While the memorandum includes provisions for passenger cars, light-duty trucks, and support of an electric vehicle charging infrastructure, the most notable component involves vehicles that have eluded fuel efficiency regulators.
When it comes to GHG emissions and the transportation sector, the elephant in the room has been medium- and heavy-duty vehicles (freight trucks). The recently released memorandum will bring these vehicles under the regulatory umbrella and increase the likelihood that the transportation sector will contribute its share to economy-wide GHG emission reductions.
- Advanced biohydrocarbons – as defined in this fact sheet – are derived from lignocellulosic biomass (e.g., trees, grasses, wastes, and agricultural or forest residues) or algae and do not compete with the production of feed or food crops.
- Depending on technology advancement and capital investment in biorefineries, some estimates have advanced biohydrocarbons displacing as much as 30 percent of the amount of petroleum consumed in the United States by 2050.
Advanced biohydrocarbons are similar to conventional hydrocarbon fuels such as gasoline or diesel but are produced from biomass feedstocks, such as woody biomass or algae, through a variety of biological and chemical processes. Advanced biohydrocarbons are considered a ‘drop-in’ fuel; in other words, their use does not require significant modifications to existing fuel distribution infrastructure or vehicle engine modifications (for gasoline or diesel powered vehicles), unlike ethanol as it is used today. Similarly, the energy content of advanced biohydrocarbons is equivalent to that of their petroleum-based counterparts (i.e., gasoline and diesel).
Manufacturers can produce advanced biohydrocarbons by four primary pathways:
- Fermentation: In this case, manufacturers pre-treat the biomass with heat, enzymes, or acids to make the cellulose easier to break down into simple sugars using a chemical reaction called hydrolysis. The sugars from the biomass are subsequently fermented using genetically engineered microorganisms. This process is similar to the one used to produce corn or sugarcane ethanol (see Climate Techbook: Ethanol). However, these microorganisms are engineered to break down the biomass to produce hydrocarbons rather than alcohols. This is an important distinction in the genetic modification of the microorganisms because alcohol formation generally would create a poisonous environment, thereby reducing the efficacy of the catalyst. With the modified microorganisms, however, hydrocarbons immediately form an organic layer separate from the microorganisms.
- Gasification: In this pathway, solid woody biomass is leftuntreatedand then converted at very high temperatures into a combination of carbon monoxide (CO) and hydrogen (H2), a mixture termed syngas. Syngas is the starting material for catalytic chemical reactions, such as Fischer-Tropsch synthesis, which convert the syngas into a liquid fuel.
- Pyrolysis: Similar to gasification, untreated woody biomass is heated quickly at high temperatures, but in the absence of oxygen. The high heating leads to the breakdown of the complex structure of the lignin to produce an intermediate bio-oil. Typically, this bio-oil is subsequently refined to a liquid fuel via a catalytic reaction called hydrotreating.
- Algal conversion: There are currently three main pathways to produce a fuel from algae: 1) algae is genetically engineered to secrete bio-oils efficiently; 2) a bio-oil extract from algae is chemically treated to produce a bio-oil; or 3) algae cultures are converted in their entirety via pyrolysis (see above). In any case, the algae can be genetically modified to thrive in otherwise harsh conditions (e.g., high salinity or nonpotable water). In all cases, the bio-oil product derived from algae is subsequently upgraded via hydrotreating and becomes a liquid fuel similar to diesel or gasoline.
Figure 1: Production Pathways for Advanced Biohydrocarbon Fuels
This figure illustrates a) chemical (black), b) biological (green), and c) thermal (red) production pathways for advanced biohydrocarbons derived from i) woody biomass and ii) algae. The production of gasoline or diesel equivalents is dependent on the technology and pathway. Note that while jet fuel can also be produced, it is not discussed further in this summary.
- Biological and Chemical Catalysts: In each of these four pathways, liquid biofuels are formed as the result of biological and chemical catalysis. Catalysis is a process in which a material (the catalyst) is added to a reactive environment to increase the rate of reaction without being consumed by the reaction. As shown in Figure 1, most of these pathways are processes that are characterized as chemical catalysis. Chemical catalysts have a number of advantages over biological catalysts. The advantages of chemical catalysts include: broader range of reaction conditions, lower residence time (i.e., faster reactions), potential for lower cost fuel production, and the elimination of a sterilization step. However, compared to biological catalysis, chemical catalysis, as it relates to the complex structures of the compounds that make up biomass, is a relatively new field. Developing these processes is a challenge.
Environmental Benefit / Emission Reduction Potential
The environmental benefits of advanced biohydrocarbons are significant. For instance, they have the potential to overcome obstacles related to the use of ethanol: land use changes; transportation and distribution of finished fuel; impacts on other agricultural commodities; and the need for vehicle modification.
The primary feedstocks for advanced biohydrocarbons are woody biomass (primarily food and agricultural waste) and algae — neither of which have the same land requirements as biofuels derived from traditional food or feed crops (such as corn or sugarcane). While there will inevitably be some pressure on agricultural lands and forestry resources, the impacts are less than first generation biofuels.
The development of heterogeneous chemical catalysts, used in combination with biological catalysts to produce advanced biohydrocarbons, has the potential to improve biofuel production efficiency and reduce costs. Furthermore, advanced biohydrocarbon fuels are chemically equivalent to the fuels derived from petroleum, which may make it possible to link biorefining processes to existing petroleum refineries. This has the potential to reduce the environmental impact of construction of new refineries and distribution networks (e.g., pipelines), and other fueling infrastructure.
Advanced biohydrocarbons have the potential to reduce significantly the amount of water used in feedstock production and in fuel processing compared to the crops for “first generation” biofuels and the processing using dilute sugar solutions for ethanol production.
The greenhouse gas emissions reduction potential of advanced biohydrocarbons is significant. However, there are no reliable estimates of the GHG emissions (reported as grams per megajoule, g/MJ) of advanced biohydrocarbons because there are no commercial scale processes that can be used to develop the appropriate energy balance equations.
The Department of Energy (DOE) has estimated that the availability of domestic biomass streams, with “relatively modest changes in land use and agricultural and forest practices,” could yield advanced biohydrocarbons at a volume equivalent to approximately 30 percent of petroleum used in the United States by 2050. The oil yield of algal-based diesels is predicted to be as much as an order of magnitude higher than other biodiesel crops. Assuming a lower limit for the oil yield of algal-based biodiesel (30 percent by weight), only 2.5 percent of existing U.S. cropping area would be required to displace 50 percent of petroleum based diesel use in the United States.
The current cost of large-scale production of advanced biohydrocarbons is unknown, as only bench-scale production has been conducted thus far. As such, only estimates of cost are available at this time.
There are four primary factors that determine the cost of the finished product: the feedstock, chemical processing (e.g., pyrolysis), refining and finishing the crude product, and the transportation and distribution of finished fuel.
Feedstock: The cost of woody biomass feedstocks is dependent on a number of factors including, but not limited to: crop yield, land availability, harvesting, storage and handling, and transportation costs. Huber estimates a cost of $34 to $70 per dry ton, or $5 to $15 per barrel of oil energy equivalent. This is generally consistent with the BRDI review of the literature. They report costs for a number of advanced biofuel feedstock types, including agricultural residues (e.g., corn stover), forest biomass, urban woody wastes and secondary mill residues, herbaceous energy crops (e.g., switchgrass), and short rotation woody crops.
Catalyst: The long-term potential of advanced biohydrocarbons is linked to the ability of producers to produce liquid fuels using cost-effective catalysts. Looking at existing catalytic processes, the DOE has a projected cost of cellulase enzymes for the production of ethanol between $0.30–0.50 per gallon of ethanol. In contrast, the chemical catalysts in the petroleum industry are estimated to cost about $0.01 per gallon of gasoline.
Refining and Upgrading: Estimates for refining and upgrading the bio-oil produced from pyrolysis or hydrolysis suggest that these steps account for about 33–39 percent of the capital costs of producing the finished product. The range varies due to the variable amount of refining and upgrading required based on the pathway.
Transportation: The cost of transporting biomass feedstocks can increase production costs considerably. The savings derived from economies of scale at centralized facilities are often offset by the increased transportation costs of the raw material(s). Developing a distribution system that is built on local and distributed production facilities rather than large centralized facilities will help reduce transportation costs.
In terms of net production, various start-up companies have claimed that they anticipate that in the long term, advanced biohydrocarbons will be competitive with conventional petroleum products at oil prices of about $40–60 per barrel.
Advanced biohydrocarbons are currently in the development and demonstration stage. A variety of processes have been demonstrated using bench-scale reactors to produce liquid fuels and liquid fuel components (e.g., aromatic compounds). Most estimates suggest that commercial scale production of advanced biohydrocarbons will begin within the next five to ten years.
Most recently, the DOE’s ARPA-E awarded seven projects (out of 37) a total of $37.2 million (out of $151 million) in areas related to advanced biohydrocarbons as part of their solicitation for Transformational Energy Research Projects.
The DOE awarded $78 million for the development of ‘drop-in’ renewable hydrocarbon biofuels such as advanced biohydrocarbons and associated fueling infrastructure.
Within the past year alone, five major oil companies – BP, Chevron, ExxonMobil, Royal Dutch Shell, and Total – announced joint ventures with biofuel companies to work on the development of advanced biohydrocarbons.
Obstacles to Further Development or Deployment
Currently, there are no low-cost technologies to convert the large fraction of energy in biomass or the bio-oils derived from algae into liquid fuels efficiently. Production costs must be reduced considerably, and the production volumes necessary for widespread use still need to be demonstrated. The lower limit benchmark for commercial scale processing of biomass is about 150,000 metric tons per year.
Ultimately, the optimization of advanced biohydrocarbon production processes is an essential step to allow biorefineries to produce up to commercial volumes. These barriers exist in processes such as selective thermal processing, liquid-phase catalytic processing of sugars and bio-oils, and catalytic conversion of bio-gas.
- Selective thermal processing via pyrolysis
- The production of bio-oil using fast pyrolysis results in a product that is high in oxygen content. This bio-oil is not compatible with the existing fueling infrastructure, so the oxygen needs to be removed, typically via hydrotreatment or hydrocracking. This process can be expensive and requires large quantities of hydrogen.
- Another concern is that bio-oils tend to be acidic and can cause corrosion in standard refinery units. Furthermore, they are toxic and require careful handling.
- Liquid-phase catalytic processing of sugars and bio-oils
- There is a need to increase our understanding of the intermediate processes during liquid-phase catalytic processes, namely the composition of the intermediate components, to help researchers tailor the finished product.
- Catalyst development for biohydrocarbon production is difficult because of the aqueous (i.e., water-based) environment. The catalysts developed in the petroleum and petrochemical refining industries are unstable under aqueous conditions as they operate in the gas phase or in organic solvents.
- There are also limitations related to the stability of the catalyst. For instance, a catalyst that works on bench scale may break down when applied to biomass feeds because of the various impurities present in the feedstock.
- Catalytic conversion of bio-gas
- Cost-effective production of bio-gas is challenging because the quantity of biomass required for commercial production is either not readily accessible or is currently being used for other purposes. Currently, gasification is done on a small scale (10,000-20,000 barrels per day of oil equivalent) at the local level which increases the costs of fuel distribution.
- The clean-up of bio-gas is an important step to streamline the processing of advanced biohydrocarbons. Bio-gas can contain impurities due to the various biomass feedstocks used in its production, which may require the development of feedstock-dependent catalysts.
- In addition to the conversion to bio-gas and the clean-up, the final step of conversion of bio-gas to liquid fuel requires considerable advancement in areas including the Fischer-Tropsch Synthesis, reactor technologies, and the integration of catalysts and reactors.
Policy Options to Help Promote Advanced Biohydrocarbon Fuels
Federal, state, county, and local governments support advanced biohydrocarbons in a variety of ways. Although current policies are aimed at alcohol transportation fuels, recent debate over the potential environmental and societal impacts of using feed and food crops for energy production has bolstered interest in biofuels produced from non-food feedstocks. Current support for advanced biohydrocarbons generally falls into three categories: 1) policies that mandate levels of use of biofuels, 2) policies that offer subsidies or tax credits for fuel production and/or use, and 3) and research initiatives.
- The Energy Independence and Security Act (EISA) of 2007 established a Renewable Fuel Standard that requires the production of 100 million gallons of cellulosic biofuel in 2010 and increasing over time to 16 billion gallons of cellulosic fuel in 2022.
- The Low Carbon Fuel Standard in California requires a 10 percent reduction in the carbon intensity of transportation fuels sold in California by 2020. In order to meet these requirements, one of the strategies that can be pursued is the introduction of advanced biohydrocarbons. The credit towards the LCFS is ultimately a function of the volume sold and the reduction in lifecycle emissions of the fuel as compared to the baseline fuel, i.e. gasoline or diesel.
Existing taxes and subsidies
- Registered cellulosic biofuel providers are eligible to receive a tax incentive up to $1.01 per gallon of biofuel that is sold and used by the purchaser in the purchaser's trade or business to produce a cellulosic biofuel mixture; sold and used by the purchaser as a fuel in a trade or business; sold at retail for use as a motor vehicle fuel; used by the producer in a trade or business to produce a cellulosic biofuel mixture; or used by the producer as a fuel in a trade or business. Biodiesel blenders can claim a tax credit of $1 per gallon. Note that only blenders that have produced and sold or used the qualified biodiesel mixture as a fuel in their trade or business are eligible for the tax credit.
Other tax and subsidy policies that may be considered:
- Promote additional tax incentives for processes and biorefineries that use biomass feedstocks from non-food sources.
- Support distribution and transportation infrastructure, including tax incentives to attract the required capital investments.
- Promotion of public-private partnerships for interdisciplinary research for the entire supply chain of advanced biohydrocarbons. For example, the recent DOE awards for $78 million of funding for advanced biofuels research are matched by $19 million in private and non-federal cost share funds.
- Support for research on non-food feedstock production in areas such as increased crop yields.
- Continued and focused support for the research and demonstration of conversion technologies in biohydrocarbon processing. The National Advanced Biofuels Consortia, led by NREL, received about $34 million of the recent DOE award for research to develop “infrastructure compatible, biomass-based hydrocarbon fuels.”
- Continued and increased support of bench- and pilot-scale research into the production of advanced biohydrocarbons.
Related Business Environmental Leadership Council (BELC) Company Activities
Related C2ES Resources
Further Reading / Additional Resources
Biomass Energy Data Book, 2008.
Green Car Congress, Bio-Hydrocarbons.
National Biofuels Action Plan, October 2008, Biomass Research and Development Board
Biomass Research and Development Initiative (BRDi), “The Economics of Biomass Feedstocks in the United States, A Review of the Literature,” 2008.
Chisti, Y. (2007). Biodiesel from microalgae. Palmerston North: Biotechnology Advances.
Hubert, GW, et al. “Synthesis of Transportation Fuels from Biomass: Chemistry, Catalysis, and Engineering.” Chemical Reviews, 2006, 106, pp. 4044-4098.
Perlack R., L. Wright, A. Turhollow, R. Graham, B Stokes, and D. Erbach, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply, USDA/DOE, DOE/GO-102005-2135, ORNL/TM-2005/66, April 2005.
Regalbuto, J. “Cellulosic Biofuels – Got Gasoline?” Science, Vol 325, 5492, pp. 822-824, August 2009.
NSF. “Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels: Next Generation Hydrocarbon Biorefineries”. Ed. George W. Huber, 2008, 180 p.
Green Car Congress, “Terrabon to Open New Demonstration Facility Next Week for Biomass to Renewable Gasoline Technology,” October 2008.
Wu, M.; Mintz, M.; and Wang, M. Water Consumption in the Production of Ethanol and Petroleum Gasoline,” Env Mngmt, 44, 981-997, 2009.
 See Perlack R., L. Wright, A. Turhollow, R. Graham, B Stokes, and D. Erbach, Biomass as Feedstock for a “Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply,” USDA/DOE, DOE/GO-102005-2135, ORNL/TM-2005/66, April 2005. In their report, Perlack et al. answer the question as to whether the “land resources of the United States are capable of producing a sustainable supply of biomass sufficient to displace 30 percent or more of the country’s present petroleum consumption.” Their scenario assumes “relatively modest changes” in land use and agricultural and forestry practices. In other words, the report evaluates the resource availability, rather than the economic viability of biomass as a feedstock for transportation fuels.
 An example of a biological catalyst is yeast in the fermentation of sugars yielded from the starch in corn or sugarcane. Biological catalysts in fermentation (to produce alcohol) have been used for thousands of years.
 Heterogeneous catalysts are those that are in a different phase (i.e., gas, liquid, or solid) than the reactants.
 Wu, M., Mintz, M., and Wang, M. “Water Consumption in the Production of Ethanol and Petroleum Gasoline,” Env Mngmt, 44, 981-997, 2009.
 Perlack et al. 2005.
 Chisti, Y. Biodiesel from microalgae. Palmerston North: Biotechnology Advances. 2007.
 Biomass Research and Development Initiative (BRDi), “The Economics of Biomass Feedstocks in the United States, A Review of the Literature,” 2008.
 Hubert, GW, et al. “Synthesis of Transportation Fuels from Biomass: Chemistry, Catalysis, and Engineering.” Chemical Reviews, 2006, 106, pp. 4044-4098.
 National Science Foundation, “Breaking the Chemical and Engineering Barriers to Lignocellulosic Biofuels: Next Generation Hydrocarbon Biorefineries,” Ed. George W. Huber, 2008, p. 180.
 NSF/Huber 2008.
 Regalbuto, J. “Cellulosic Biofuels – Got Gasoline?” Science, Vol 325, 5492, pp. 822-824, August 2009 and Green Car Congress, “Terrabon to Open New Demonstration Facility Next Week for Biomass to Renewable Gasoline Technology,” October 2008,” October 2008.
 LS9. “LS9 Secures $25 Million in Latest Round of Funding.” Press Release, September 2009.
 Shell and Codexis. “Shell and Codexis Deepen Collaboration to Speed Arrival of Next Generation Biofuel.” Joint Press Release, October 2009.
 Gevo, Inc. “Major Oil and Gas Company, Total, Invests in Advanced Biofuels Leader Gevo.” Press Release, April 2009.
 NSF/Huber 2008.
 U.S. Department of Energy. Alternative Fuels and Advanced Vehicles Data Center – Federal and State Incentives and Laws. Last accessed March 19th, 2010.
With the long-awaited release of the Kerry-Lieberman clean energy and climate bill (The American Power Act) and EPA’s final action on its “tailoring” rule, two important clues emerged this week to the unfolding mystery of whether or not we will have climate legislation this year. And buckle up and enjoy the ride -- two more major developments are just around the corner. On Wednesday, the National Academy of Sciences will be releasing three of its panel reports on America’s Climate Choices and sometime in the next two weeks Senator Murkowski may bring forward for a vote her effort to overturn EPA’s endangerment finding.
The release of the K-L bill demonstrates both how far we have gone and how distant the goal remains. The bill achieved support from some key elements of the business community and goes much further in adding in elements (nuclear power and a hard price collar) that could expand its base of support. But the loss of Senator Graham as a co-sponsor and the absence of any bipartisan backing underscore the challenges it faces in achieving the 60 votes it will need to avoid a filibuster in the Senate. The Senate clock also continues to wind down making it harder to find floor time to move a comprehensive bill forward.
EPA’s recently issued interpretation of when greenhouse gases become regulated pollutants and its final tailoring rule show EPA’s willingness to make reasonable use of the existing Clean Air Act to tackle climate change. By delaying the effective date when new source review will apply to greenhouse gases, and limiting new source requirements for best available control technology to only the largest sources (estimated to impact approximately 900 additional major sources annually), the agency put to rest the fears of some that the Agency’s rules would sink the economy and harm small businesses. The rule shows that the existing Act, though cumbersome, can be used as a tool to reduce greenhouse gas emissions.
Both EPA’s action and the upcoming National Academy panel reports provide the perfect preface to the expected vote in the Senate on overturning EPA’s endangerment finding which links greenhouse gas emissions to health and welfare impacts from climate change. To argue for overturning the finding, some Senators will point to recent controversies: the errors in the IPCC report; the hacked e-mails referred to as “climategate;” and even the DC snowstorms of last winter as evidence that the science of climate change is somehow suspect. Despite the media attention these have received, none in any way undercut the overwhelming case underlying concerns about climate change. Three independent investigations have each cleared the scientists who authored the e-mails of charges that they manipulated data or infringed on the peer review process. The IPCC has corrected the two mistakes (the expected date of the melting of Himalayan glaciers and the percent of land in the Netherlands under water) uncovered to date in its reports – out of a total of thousands of pages, two mistakes neither of which undercuts the IPCC’s key conclusion that “warming of the climate system is unequivocal” and “that most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.” Finally, notwithstanding Washington D.C.’s blustery winter, globally 2009 proved to be one of the warmest years on record. The NAS panel reports this week are likely only to reinforce these conclusions, further calling into question any votes in support of overturning EPA’s endangerment finding based on denying what we know about climate science.
Others in the Senate, including Senator Murkowski, make the case that the goal of overturning the endangerment finding is really about the need to take the worst option (EPA regulations) off the table and thereby protect our economy from the potentially dire consequences of EPA action particularly on small businesses. They argue that this would allow our elected representatives the opportunity and time to address this issue. But the limits EPA adopted in its tailoring rule (and its earlier decision to delay implementation) appear to take off the table these concerns about widespread and costly controls on small sources. Although legal challenges to the tailoring rule are possible, they would take time to work their way through the courts, and if they were successful, Congress would then be in a far better position (and have a more compelling case) to provide a narrow legislative fix addressing a specific problem.
When the debate on overturning EPA’s endangerment finding moves to the Senate floor (10 hours of debate is permitted), many will be wondering why the Senate isn’t instead focusing its debate on finding the common ground solutions urgently needed to get our nation on a path that enhances our energy independence, spurs the growth of new technologies, and slows climate change.
Steve Seidel is Vice President for Policy Analysis
Our corporate energy efficiency conference opened by answering the big question: What actions should businesses take to reduce energy use?
- Don't just set goals, set big hairy audacious ones even if you may not know exactly how to achieve them, asserted PepsiCo.
- Efficiency is done better together – you have to get all your business units moving forward on efficiency, advised IBM.
- Make the data visible – quarterly scorecards on efficiency measures lead to shared knowledge, clear measures against goals and the ability to hold leaders accountable and reward those who deliver results, suggested Dow Chemical.
- Show them the money – you need to show everyone from the board room to the boiler room that energy efficiency is good for business, stressed Toyota.
So how do you do all this? The solutions-oriented conference provided answers through panels covering the various components of corporate energy efficiency.
The conference marked the launch of our recent report, "From Shop Floor to Top Floor: Best Business Practices in Energy Efficiency" authored by William Prindle, Vice President of ICF International. Held April 6-7 in Chicago, the two-day conference brought together a diverse audience, including representatives of numerous companies with products ranging from software to soft drinks.
The conference was kicked off with presentations from six companies whose best practices in energy efficiency were highlighted in the report's case studies (Best Buy, Dow Chemical, IBM, PepsiCo, Toyota, and UTC). Subsequent panels examined issues such as overcoming financial barriers in pursuing energy efficiency projects, gaining senior level support for energy efficiency, engaging employees, suppliers and customers in energy efficiency efforts, and the challenges of gathering and reporting energy efficiency data.
In every panel session there was an abundance of questions, and lively discussions spilled out into the hallways during breaks. Panelists discussing financial barriers to energy efficiency were asked about building a financial case for employee engagement programs, PACE financing, and tradable energy efficiency certificates. Attendees had panelists pondering the idea of a best-of-the-best list within the joint U.S. DOE/U.S. EPA ENERGY STAR program and how to include supply chain efficiency metrics in labeling. How to keep employees engaged in energy efficiency measures and bringing suppliers into the fold were other key questions asked of conference panelists.
While the discussions mostly focused on what companies can do to be more energy efficient, the broader issue of climate change was not far from everyone's minds. Former Senator John Warner, a keynote speaker, was asked about the right message that would get Congress moving on climate change legislation. And keynotes John Rowe, CEO and Chairman of Exelon, and our President Eileen Claussen both noted that policy that puts a price on greenhouse gas emissions is essential to moving the United States to a low-carbon economy and addressing climate change.
Videos and presentations from the conference are available on our Web site.
Aisha Husain is an Energy Efficiency Fellow.
Previous posts in this series discussed how the demand for electricity from plug-in electric vehicles (PEVs) would affect the grid as well as a potential problem related to clustering. This final post describes an opportunity for these vehicles to help increase the stability of the grid and hold down utility rates for consumers. As a reminder, a PEV is either an all-electric vehicle (EV) or a plug-in hybrid electric vehicle (PHEV).
In our previous post in this series, we provided evidence that the existing electrical grid has enough spare capacity to accommodate plenty of plug-in electric vehicles (PEVs), if the right incentives are put in place. In this post, we will discuss a technical problem that has its roots in social behavior.
The transition from traditional powered vehicles to electric vehicles will not be without its hiccups. While the aggregate impact of PEVs on the grid is likely moderate, one concern is clustering, which can be thought of as the realization of the famous comic strip Keeping up with the Joneses. If people buy what their neighbors have, this could lead to a clustering of PEVs in certain neighborhoods which might place excessive demand on local areas of the grid.
One of the main concerns over the electrification of vehicles is their impact on the electrical grid. Will they lead to power outages due to the increased demand in certain areas? Will a marked increase in electricity demand raise prices for consumers who don’t own a plug-in hybrid electric vehicle (PHEV) or an all-electric vehicle (EV)? In a series of blog posts, we’ll take a look at a claim from some utilities that vehicle electrification could actually help improve the stability of the grid while keeping costs low through a process called frequency regulation.
In this post, we’ll try to answer the capacity question. In order to determine whether the grid has the capacity to handle the influx of Plug-in Electric Vehicles (PEVs or PHEVs/EVs), utilities must estimate at what time of day these vehicles will demand power from the grid and how many of them the grid can charge at a time without causing power disruptions.
Earth Day – it’s the perfect day to start your energy diet. It’s great to hug a tree, (in fact, that’s how you measure the carbon it sequesters) but for most of us, it’s even better to wrap our arms around that tangle of charger cords and pull the plug. Reducing your energy consumption is the very best way to honor Mother Earth – and save money – this year and every year.
Since I am perpetually on a diet, let me share some of the best strategies for getting started: