scholarly journals LAND-USE AND GREENHOUSE GAS IMPLICATIONS OF BIOFUELS: ROLE OF TECHNOLOGY AND POLICY

2012 ◽  
Vol 03 (03) ◽  
pp. 1250013 ◽  
Author(s):  
XIAOGUANG CHEN ◽  
HAIXIAO HUANG ◽  
MADHU KHANNA

This paper examines the changes in land use in the U.S. likely to be induced by biofuel and climate policies and the implications of these policies for greenhouse gas (GHG) emissions over the 2007–2022 period. The policies considered here include a modified Renewable Fuel Standard (RFS) by itself as well as combined with a cellulosic biofuel tax credit or a carbon price policy. We use a dynamic, spatial, multi-market equilibrium model, Biofuel and Environmental Policy Analysis Model (BEPAM), to endogenously determine the effects of these policies on cropland allocation, food and fuel prices, and the mix of first- and second-generation biofuels. We find that the RFS could be met by diverting 6% of cropland for biofuel production and would result in corn prices increasing by 16% in 2002 relative to the business-as-usual baseline. The reduction in GHG emissions in the U.S. due to the RFS is about 2%; these domestic GHG savings can be severely eroded by emissions due to indirect land-use changes and the increase in gasoline consumption in the rest of the world. Supplementing the RFS with a carbon price policy or a cellulosic biofuel tax credit induces a switch away from corn ethanol to cellulosic biofuels and achieves the mandated level of biofuel production with a smaller adverse impact on crop prices. These supplementary policies enhance the GHG savings achieved by the RFS alone, although through different mechanisms; greater production of cellulosic biofuels with the tax credit but larger reduction in fossil fuel consumption with a carbon tax.

2017 ◽  
Vol 7 (1) ◽  
pp. e00125 ◽  
Author(s):  
Andrea Nocentini ◽  
John Field ◽  
Andrea Monti ◽  
Keith Paustian

2012 ◽  
Vol 03 (03) ◽  
pp. 1250012 ◽  
Author(s):  
ROBERT H. BEACH ◽  
YUQUAN W. ZHANG ◽  
BRUCE A. MCCARL

Biofuels production has increased rapidly in recent years due to higher petroleum prices as well as heightened concerns regarding climate change and energy security. However, because commercially viable biofuels are currently produced primarily from agricultural feedstocks, higher production volumes increase pressure on land resources. Thus, large-scale biofuels production has important implications for the forest and agriculture sectors, land use, trade, and net greenhouse gas (GHG) emissions. Competition for land is expected to continue growing in the future as mandated biofuels volumes increase along with rising demand for food, feed, and fiber, both domestically and internationally. In response to heightened concern regarding impacts such as indirect land-use change and higher food prices, the U.S. policy is focusing on second-generation (cellulosic) feedstocks to contribute the majority of the mandated increase in biofuels volume through 2022. However, there has been little work exploring the logistics of supplying these feedstocks or examining feedstock mix and net GHG effects of combining renewable fuels mandates with climate policy. In this paper, we apply the recently updated Forest and Agricultural Sector Optimization Model with GHGs (FASOMGHG) to explore the implications of alternative assumptions regarding feedstock storage costs and carbon price for renewable energy production mix, land use, and net GHG emissions. The model is used to quantify the magnitude and regional distribution of changes in the optimal mix of bioenergy feedstocks when accounting for storage costs. In addition, we find that combining the biofuels volume mandate with a carbon price policy has additional implications for feedstock mix and provides a substantially larger net reduction in GHG than a renewable fuels mandate alone.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Shannon M. Hoffman ◽  
Maria Alvarez ◽  
Gilad Alfassi ◽  
Dmitry M. Rein ◽  
Sergio Garcia-Echauri ◽  
...  

Abstract Background Future expansion of corn-derived ethanol raises concerns of sustainability and competition with the food industry. Therefore, cellulosic biofuels derived from agricultural waste and dedicated energy crops are necessary. To date, slow and incomplete saccharification as well as high enzyme costs have hindered the economic viability of cellulosic biofuels, and while approaches like simultaneous saccharification and fermentation (SSF) and the use of thermotolerant microorganisms can enhance production, further improvements are needed. Cellulosic emulsions have been shown to enhance saccharification by increasing enzyme contact with cellulose fibers. In this study, we use these emulsions to develop an emulsified SSF (eSSF) process for rapid and efficient cellulosic biofuel production and make a direct three-way comparison of ethanol production between S. cerevisiae, O. polymorpha, and K. marxianus in glucose and cellulosic media at different temperatures. Results In this work, we show that cellulosic emulsions hydrolyze rapidly at temperatures tolerable to yeast, reaching up to 40-fold higher conversion in the first hour compared to microcrystalline cellulose (MCC). To evaluate suitable conditions for the eSSF process, we explored the upper temperature limits for the thermotolerant yeasts Kluyveromyces marxianus and Ogataea polymorpha, as well as Saccharomyces cerevisiae, and observed robust fermentation at up to 46, 50, and 42 °C for each yeast, respectively. We show that the eSSF process reaches high ethanol titers in short processing times, and produces close to theoretical yields at temperatures as low as 30 °C. Finally, we demonstrate the transferability of the eSSF technology to other products by producing the advanced biofuel isobutanol in a light-controlled eSSF using optogenetic regulators, resulting in up to fourfold higher titers relative to MCC SSF. Conclusions The eSSF process addresses the main challenges of cellulosic biofuel production by increasing saccharification rate at temperatures tolerable to yeast. The rapid hydrolysis of these emulsions at low temperatures permits fermentation using non-thermotolerant yeasts, short processing times, low enzyme loads, and makes it possible to extend the process to chemicals other than ethanol, such as isobutanol. This transferability establishes the eSSF process as a platform for the sustainable production of biofuels and chemicals as a whole.


2011 ◽  
Vol 1 (2) ◽  
pp. 224-232 ◽  
Author(s):  
Andre M. Nassar ◽  
Leila Harfuch ◽  
Luciane C. Bachion ◽  
Marcelo R. Moreira

The use of agricultural-based biofuels has expanded. Discussions on how to assess green house gas (GHG) emissions from biofuel policies, specifically on (non-observed) land-use change (LUC) effects involve two main topics: (i) the limitations on the existing methodologies, and (ii) how to isolate the effects of biofuels. This paper discusses the main methodologies currently used by policy-makers to take decisions on how to quantify LUCs owing to biofuel production expansion. It is our opinion that the concerns regarding GHG emissions associated with LUCs should focus on the agricultural sector as a whole rather than concentrating on biofuel production. Actually, there are several limitations of economic models and deterministic methodologies for simulating and explaining LUCs resulting from the expansion of the agricultural sector. However, it is equally true that there are avenues of possibilities to improve models and make them more accurate and precise in order to be used for policy-making. Models available need several improvements to reach perfection. Any top model requires a concentration of interdisciplinary designers in order to replicate empirical evidence and capture correctly the agricultural sector dynamics for different countries and regions. Forgetting those limitations means that models will be used for the wrong purposes.


2012 ◽  
Vol 03 (03) ◽  
pp. 1250015 ◽  
Author(s):  
ALLA A. GOLUB ◽  
THOMAS W. HERTEL

This paper reviews an analysis of land use change impacts of expanded biofuel production with GTAP-BIO computable general equilibrium (CGE) model. It describes the treatment of energy substitution, the role of biofuel by-products, specification of bilateral trade, the determination of land cover changes in response to increased biofuel feedstock production, and changes in crop yields – both at the intensive and extensive margins. The paper responds to some of the criticisms of GTAP-BIO and provides insights into the sensitivity of land use change and GHG emissions to changes in key parameters and assumptions. In particular, it considers an alternative specification of acreage response that takes into account the degree of land heterogeneity within agro-ecological zone (AEZ) for different AEZs and countries. The paper concludes with the discussion of alternative specifications of land mobility across uses employed in CGE models and the agenda for further research to narrow parametric and structural uncertainty to improve the model's performance.


2011 ◽  
Vol 6 (2) ◽  
pp. 66-87 ◽  
Author(s):  
Adele Houghton

Historical records have documented considerable changes to the global climate, with significant health, economic, and environmental consequences. Climate projections predict more intense hurricanes; increased sea level rise; and more frequent and more intense natural disasters such as heat waves, heavy rainfall, and drought in the future (1; 2). The coast along the Gulf of Mexico is particularly vulnerable to many of these environmental hazards and at particular risk when several strike simultaneously—such as a hurricane disrupting electricity transmission during a heat wave. Due to its significant contribution to global greenhouse gas (GHG) emissions, the building sector already plays an important role in climate change mitigation efforts (e.g., reducing emissions). For example, voluntary programs such as the LEED (Leadership in Energy and Environmental Design) Rating System (3), the Architecture 2030 Challenge (4), the American College and University Presidents' Climate Commitment (5), and the Clinton Climate Initiative (6) focus almost exclusively on reducing energy consumption and increasing renewable energy generation. Mandatory regulations such as the International Energy Conservation Code (7), the International Green Building Code (8), and CalGreen (9) also emphasize GHG emission reduction targets. This leadership role is necessary. After all, the United States EPA estimates that the building sector accounts for 62.7% of total annual GHG emissions in the U.S., when the construction sector, facility operations, and transportation are factored in. In fact, the construction sector alone is the third largest industrial emitter of GHGs after the oil and gas and chemical industries, contributing 1.7% of total annual emissions (10; 11). As significant as these contributions appear, the built environment's true contribution to climate change is much larger than the GHG emissions attributed to building construction and operations. It is also a major determinant of which populations are vulnerable to climate change-related hazards, such as heat waves and flooding (12; 13). Architecture and land use planning can therefore be used as tools for building community resilience to the climate-related environmental changes underway (13). Climate change regulations and voluntary programs have begun to incorporate requirements targeting the built environment's ability to work in tandem with the natural environment to both reduce greenhouse gas emissions and protect its occupants from the health consequences of a changing climate. For example, 11 states have incorporated climate change adaptation goals into their climate action plans (14). In 2010, the not-for-profit organization ICLEI: Local Governments for Sustainability launched a climate change adaptation program (15) to complement their existing mitigation program, which supports municipalities who have signed the U.S. Conference of Mayors' Climate Protection Agreement (16). New tools have been introduced to measure community vulnerability to the impacts of climate change. One of these tools, Health Impact Assessments (or HIAs), has emerged over the past decade as a powerful methodology to provide evidence-based recommendations to decision makers and community planning officials about the likely health co-benefits and co-harms associated with proposed policies and land use development proposals (17). While HIAs are becoming a more common feature of community planning efforts, this paper introduces them as an approach to designing climate change resilience into specific building projects. HIAs have been used in Europe and other parts of the world for decades to provide a science-based, balanced assessment of the risks and benefits to health associated with a proposed policy or program (18). In the U.S., they have been used over the past decade to evaluate transit-oriented developments, urban infill projects, and California's capand-trade legislation, among other topics (17; 19). To date, HIAs have been used mainly to inform large-scale community planning, land use, industrial, and policy decisions. However, the recommendations generated through the HIA process often bring to light previously unforeseen vulnerabilities, whether due to existing infrastructure, building technology, or socio-economic conditions. Designers can make use of the HIA process and its resulting recommendations to prioritize design/retrofit interventions that will result in the largest co-benefits to building owners, the surrounding community, and the environment. An HIA focused on the health impacts of climate change will likely generate recommendations that could enhance the longevity of a building project's useful life; protect its property value by contributing to the resilience of the surrounding community; and result in design decisions that prioritize strategies that maximize both short-term efficiencies and long-term environmental, economic, and social value.


2019 ◽  
Vol 97 (9) ◽  
pp. 4010-4020 ◽  
Author(s):  
Claire B Gleason ◽  
Robin R White

Abstract The increasing global population, limited resource availability, and global focus on reducing greenhouse gas (GHG) emissions put pressure on animal agriculture industries to critically evaluate and optimize the role they play in a sustainable food production system. The objective of this review is to summarize evidence of the various roles that the U.S. beef industry plays in the U.S. and global agricultural systems. As the world’s largest beef producer, the United States reaps considerable economic benefit from the beef industry through strong domestic and international demand, as well as employment opportunities for many Americans. Beef production contributes to GHG emissions, land use, and water use, among other critical environmental impacts but provides an important source of essential micronutrients for human consumption. The U.S. beef industry provides sufficient product to meet the protein, vitamin B12, omega-3 and -6 fatty acid requirements of 43, 137, 47, and 487 million people, respectively. In the United States, beef production was estimated to account for 53% of GHG emissions from U.S. animal agriculture and 25% of GHG emissions from all of U.S. agriculture. Footprinting studies suggest that much of the land use and water use associated with beef production are attributed to the development of feed crops or pastureland. On a global scale, beef from U.S. origin is exported to numerous developed and developing countries, representing an important international nutrient routing. Along with other prominent beef-producing nations, the United States continues to pursue a greater level of sustainability in its cattle industry, which will bear important implications for future global food security. Efforts to reduce the environmental impacts of beef production will likely be the strongest drivers of enhanced sustainability.


2020 ◽  
Vol 117 (36) ◽  
pp. 21968-21977 ◽  
Author(s):  
John L. Field ◽  
Tom L. Richard ◽  
Erica A. H. Smithwick ◽  
Hao Cai ◽  
Mark S. Laser ◽  
...  

Biofuel and bioenergy systems are integral to most climate stabilization scenarios for displacement of transport sector fossil fuel use and for producing negative emissions via carbon capture and storage (CCS). However, the net greenhouse gas mitigation benefit of such pathways is controversial due to concerns around ecosystem carbon losses from land use change and foregone sequestration benefits from alternative land uses. Here, we couple bottom-up ecosystem simulation with models of cellulosic biofuel production and CCS in order to track ecosystem and supply chain carbon flows for current and future biofuel systems, with comparison to competing land-based biological mitigation schemes. Analyzing three contrasting US case study sites, we show that on land transitioning out of crops or pasture, switchgrass cultivation for cellulosic ethanol production has per-hectare mitigation potential comparable to reforestation and severalfold greater than grassland restoration. In contrast, harvesting and converting existing secondary forest at those sites incurs large initial carbon debt requiring long payback periods. We also highlight how plausible future improvements in energy crop yields and biorefining technology together with CCS would achieve mitigation potential 4 and 15 times greater than forest and grassland restoration, respectively. Finally, we show that recent estimates of induced land use change are small relative to the opportunities for improving system performance that we quantify here. While climate and other ecosystem service benefits cannot be taken for granted from cellulosic biofuel deployment, our scenarios illustrate how conventional and carbon-negative biofuel systems could make a near-term, robust, and distinctive contribution to the climate challenge.


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