Methane digesters and biogas recovery - masking the environmental consequences of industrial concentrated livestock production.

Author:Di Camillo, Nicole G.
  1. INTRODUCTION II. METHANE DIGESTERS AND BIOGAS RECOVERY--IN THE SPOTLIGHT A. Digesters Have Received Attention for Their Potential to Mitigate Greenhouse Gas Emissions from Livestock Production Facilities B. How Digesters Work--Their Potential for Environmental Benefits" and Renewable Energy Production C. Critiques of Digesters--Pollution Problems and Applicability Limited to Large CAFO-Style Facilities 1. Digesters Release "Traditional" Air Pollutants 2. Digesters Do Not Address the Large Quantities of Manure Generated by Large Scale Livestock Production 3. Digesters are Expensive to Install and are Typically Only Cost-Effective for Large, CAFO-Scale Facilities III. EVEN BEYOND MANURE-ASSOCIATED METHANE EMISSIONS, INDUSTRIAL LIVESTOCK OPERATIONS ARE MAJOR CONTRIBUTORS TO GREENHOUSE GAS EMISSIONS A. Methane from Manure Accounts for a Relatively Small Portion of Livestock Associated Methane Emissions B. An Analysis of The Livestock Industry's Entire "Chain of Supply" Reveals Enormous Contributions to Greenhouse Gas Emissions 1. Feed Crop Production 2. Land Use Changes Associated with Feed Crop Production Contribute to Greenhouse Gas Emissions 3. The Final Stages--Fossil Fuel Use in Processing, Storing and Transport of Feed and Consumer Products Results in the Release of Greenhouse Gas Emissions C. Subsidies for Digesters Distract from the Broad Range of Greenhouse Gas Emissions Associated with Industrial Livestock Production IV. THE INDUSTRIAL LIVESTOCK INDUSTRY'S CONTRIBUTION TO "TRADITIONAL POLLUTANTS" AND REGULATION UNDER EXISTING ENVIRONMENTAL LAWS A. The Environmental Consequences of Industrial Livestock Production 1. Environmental Consequences of Manure 2. Other Environmental and Health Consequences Stemming from CAFOs B. Traditional Pollution Control Laws-Regulation of CAFOs Should be Secured and Expanded Under the Clean Air Act and Clean Water Act 1. Air Pollution--CAFOs' Contribution to Air Pollution Warrant Regulation Under the Clean Air Act 2. Water Pollution--CAFOs' Contributions to Water Pollution and Contamination Warrant More Stringent Regulation Under the Clean Water Act C. Digesters and Other "Technological Fixes" Can Dovetail with Increased Regulation of CAFOs, but Should Not "Greenwash" CAFOs' Environmental Practices V. CONCLUSION I. INTRODUCTION

    As climate change becomes a prominent focus in environmental protection policy, the agriculture sector's role in greenhouse gas emissions is gaining attention. It has become clear that agriculture, and livestock production in particular, are major worldwide contributors to greenhouse gas emissions, and government agencies are seeking solutions to deal with these emissions. Methane digesters ("digesters"), alternatively referred to as "dairy digesters" or "anaerobic digesters," are being promoted by the U.S. Environmental Protection Agency ("EPA") and tile U.S. Department of Agriculture ("USDA") as a way to reduce greenhouse gas emissions from intensive livestock and dairy operations; the accompanying biogas recovery systems are promoted as an auspicious source of renewable energy production from such facilities. Digesters, marketed as an alternative waste management technology, ostensibly mitigate methane emissions caused by the high concentration of livestock manure stored on such facilities. They capture the methane that is released as a result of anaerobic bacterial digestion of manure, which can subsequently be burned as an alternative biogas fuel source, potentially providing economic and environmental benefits. The EPA, USDA and U.S. Department of Energy ("DOE") jointly coordinate the AgStar program, which provides financial subsidies and educational guidance for developing digester systems, and many states provide additional subsidies or tax credits for encouraging the implementation of digesters.

    The benefits of digesters are not, however, unequivocal. First, there are serious questions about the efficiency of digesters--they are very expensive, often prohibitively so without subsidies. The biogas recovery process itself creates emissions of other air pollutants, which in turn can contribute to global warming. In addition, digesters do not in fact reduce the actual quantity or nutrient load of manure, which are among the major problems associated with large-scale livestock production; in other words, at the end of the digestion process, large-scale facilities still have a large manure problem on their hands.

    Second, it is important to recognize the context in which most digesters tend to be cost-effective and profitable. Digesters are profitable, arguably only with the help of subsidies, at industrial-scale concentrated livestock facilities, often referred to as concentrated Animal Feeding Operations ("CAFOs"). (1) These facilities contribute to a host of environmental problems aside from methane emissions. Notwithstanding the benefits derived from methane digestion and biogas recovery systems extolled by the EPA and USDA, industrial livestock production in its entirety is still a major contributor to greenhouse gas emissions. Methane emissions from manure management are responsible for only a fraction of the system-wide greenhouse gas emissions associated with such production and only a small percentage--approximately seven percent--of overall methane emissions in the United States. Beyond greenhouse gas emissions, industrial livestock production contributes to "traditional" air and water pollution problems, and raises important public health concerns. Although CAFOs are a significant source of air and water pollution, their regulation under U.S. environmental laws has been inconsistent or sometimes non-existent. (2) CAFOs emit air and water pollutants (3) and water quality is consistently threatened by the large quantity and high concentration of manure stored on such facilities, (4) problems which digesters do nothing to address.

    The purported benefits of digesters must, thus, be assessed within the context of these issues so that they do not have the effect of "greenwashing" the environmental practices of large industrial livestock operations--making it seem that those who implement digesters are part of a solution instead of a major contributor to the problem. I argue in this comment that, in light of the major pollution problems associated with CAFOs, the benefits conferred by digester systems are minimal, and moreover, that the government should not offer obligation-free subsidies and resources to CAFOs to implement such systems. These systems can potentially confer economic benefits to such operations while the operators continue to practice in the same environmentally unsound manner, apart from some reduction in methane emissions. Subsidies for digester systems are an inefficient and dangerous distraction from the real environmental problems posed by CAFOs, which should be the focus of agriculture-related environmental protection efforts.

    Instead of promoting digesters, which provide only minimal environmental benefits, I argue that the government should be increasing regulation of CAFOs under existing environmental laws. CAFOs should be required to internalize the environmental costs of their method of livestock production, not subsidized to continue to produce livestock in a largely unsustainable manner. I ultimately conclude that the government should focus attention and resources not on such arguably dubious technologies as a way to address the environmental problems associated with industrial livestock production, but instead on ways of promoting more comprehensive, sustainable, long-term solutions to developing livestock and agricultural production systems which are protective of the environment and public health.

    Part I will discuss the recent attention that digesters have received from government agencies, describe the AgStar program, and explain how digester systems work. This section will also discuss some of the critiques that have been made of digester systems-in particular, criticisms that digesters contribute to other forms of air pollution, and are only feasible for industrial-scale, concentrated livestock facilities. Part II will discuss the contribution of industrial livestock operations to climate change more broadly. The focus will be on how, when viewed in the context of the entire industrial livestock commodity chain, methane from manure accounts for only a small fraction of the sector's greenhouse gas emissions. Part III will discuss how, beyond greenhouse gas emissions, industrial livestock production contributes to "traditional" pollution problems and raises significant public health concerns. This part will also review the inadequacy of current regulation of CAFOs and suggest increasing regulation. This part will conclude with the argument that, given the substantial environmental impact of CAFOs, the cost of digesters (if implemented) should be borne by CAFO operators themselves, not supported with scant public resources.


    1. Digesters Have Received Attention for Their Potential to Mitigate Greenhouse Gas Emissions from Livestock Production Facilities

      As climate change begins to take center stage in the environmental protection dialogue, dairy and livestock facilities, as well as agriculture more broadly, are beginning to garner attention. (5) Agriculture is a major international contributor of greenhouse gas emissions (GHGs)--"about one-third of the total human-induced warming effect due to GHGs comes from agriculture and land-use change." (6) In the United States, agricultural emissions constitute approximately 8% of total U.S. GHG emissions. (7) Worldwide, it is estimated that the livestock sector alone (beef and dairy cattle, swine, and poultry) accounts for 18% of GHGs, more than the transportation sector. (8) Agricultural operations release carbon dioxide, methane and nitrous oxides and "increasing evidence shows that the greater...

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