Department Personnel

David Murphy

    David Murphy

      djmurphy@niu.edu              

      

 

Publications & Presentations 

 

  


Publications

Murphy, D, Nelder, C, Jefferson, M, Hall, C, Laherrere, J, Baldauf, J, Kuperus-Heun, M, Dale, M. 2012. Peak Oil is Affecting the Economy Already. Nature 483 (541), Correspondence.

Sell B, Murphy D, Hall, C. 2011. Energy Return on Energy Invested for Tight Gas Wells in the Appalachian Basin, United States of America. Sustainability. 3: 1986-2008. Abstract 

Pelletier N, Audsley E, Brodt S, Garnett T, Henriksson P, Kendall A, Kramer K, Murphy D, Nemecek T, Troell M. 2011. Energy Intensity of Agriculture and Food Systems. Annual Review of Environment and Resources, 36: 223-246. Abstract

Murphy, D.J., Charles A.S. Hall, Michael Dale, and Cutler Cleveland. 2011. Order from Chaos: A Preliminary Protocol for Determining the EROI of Fuels. Sustainability 2011, 3, 1888-1907; doi:10.3390/su3101888 Abstract

Murphy, D.J. and Charles A.S. Hall. 2011. Energy return on investment, peak oil, and the end of economic growth in “Ecological Economics Reviews.” Robert Costanza, Karin Limburg & Ida Kubiszewski, Eds. Ann. N.Y. Acad. Sci. 1219: 52-72. Abstract

Murphy, D.J., C.A.S. Hall, and Bobby Powers. 2011. New Perspectives on the Energy Return on Investment of Corn Based Ethanol. Environment, Development and Sustainability, 13(1) pp 179-202. Abstract

Murphy, D.J. and Charles A.S. Hall. 2010. Year in review: energy return on (energy) investment in “Ecological Economics Reviews.” Robert Costanza & Karin Limburg, Eds. Ann. N.Y. Acad. Sci. 1185: 102 – 118.

Murphy, D.J., M.H.P. Hall, C.A.S. Hall, G. Heisler, S. Stehman, and Carlos Anselmi-Molina. 2009: The Relation Between Land-cover and the Urban Heat Island in Northeastern Puerto Rico. International Journal of Climatology, 31(8) pp 1222-1239.

Hall, Charles A., Stephen Balogh, David J. Murphy. 2009. What is the Minimum EROI that a Sustainable Society Must Have? Energies 2(1) pp 25 – 47.

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 Publications

Sell B, Murphy D, Hall, C. 2011. Energy Return on Energy Invested for Tight Gas Wells in the Appalachian Basin, United States of America. Sustainability. 3: 1986-2008.

Abstract
The energy cost of drilling a natural gas well has never been publicly addressed in terms of the actual fuels and energy required to generate the physical materials consumed in construction. Part of the reason for this is that drilling practices are typically regarded as proprietary; hence the required information is difficult to obtain. We propose that conventional tight gas wells that have marginal production characteristics provide a baseline for energy return on energy invested (EROI) analyses. To develop an understanding of baseline energy requirements for natural gas extraction, we examined production from a mature shallow gas field composed of vertical wells in Pennsylvania and materials used in the drilling and completion of individual wells. The data were derived from state maintained databases and reports, personal experience as a production geologist, personal interviews with industry representatives, and literature sources. We examined only the “upstream” energy cost of providing gas and provide a minimal estimate of energy cost because of uncertainty about some inputs. Of the materials examined, steel and diesel fuel accounted for more than two-thirds of the energy cost for well construction. Average energy cost per foot for a tight gas well in Indiana County is 0.59 GJ per foot. Available production data for this natural gas play was used to calculate energy return on energy invested ratios (EROI) between 67:1 and 120:1, which depends mostly on the amount of materials consumed, drilling time, and highly variable production. Accounting for such inputs as chemicals used in well treatment, materials used to construct drill bits and drill pipe, post-gathering pipeline construction, and well completion maintenance would decrease EROI by an unknown amount. This study provides energy constraints at the single-well scale for the energy requirements for drilling in geologically simple systems. The energy and monetary costs of wells from Indiana County, Pennsylvania are useful for constructing an EROI model of United States natural gas production, which suggests a peak in the EROI of gas production, has already occurred twice in the past century.

Keywords: EROI; natural gas; tight gas; Appalachian Basin; Indiana County; depletion

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Pelletier N, Audsley E, Brodt S, Garnett T, Henriksson P, Kendall A, Kramer K, Murphy D, Nemecek T, Troell M. 2011. Energy Intensity of Agriculture and Food Systems. Annual Review of Environment and Resources, 36: 223-246.

Abstract
The relationships between energy use in food systems, food system productivity, and energy resource constraints are complex. Moreover, ongoing changes in food production and consumption norms concurrent with urbanization, globalization, and demographic changes underscore the importance of energy use in food systems as a food security concern. Here, we review the current state of knowledge with respect to the energy intensity of agriculture and food systems. We highlight key drivers and trends in food system energy use along with opportunities for and constraints on improved efficiencies. In particular, we point toward a current dearth of research with respect to the energy performance of food systems in developing countries and provide a cautionary note vis-à-vis increasing food system energy dependencies in the light of energy price volatility and concerns as to long-term fossil energy availabilities.

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Murphy, D.J., Charles A.S. Hall, Michael Dale, and Cutler Cleveland. 2011. Order from Chaos: A Preliminary Protocol for Determining the EROI of Fuels. Sustainability 2011, 3, 1888-1907; doi:10.3390/su3101888

Abstract
The main objective of this manuscript is to provide a formal methodology, structure, and nomenclature for EROI analysis that is both consistent, so that all EROI numbers across various processes can be compared, and also flexible, so that changes or additions to the universal formula can focus analyses on specific areas of concern. To accomplish this objective we address four areas that are of particular interest within EROI analysis: (1) boundaries of the system under analysis, (2) energy quality corrections,  (3) energy-economic conversions, and (4) alternative EROI statistics. Lastly, we present step-by-step instructions outlining how to perform an EROI analysis. 
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Murphy, D.J. and Charles A.S. Hall. 2011. Energy return on investment, peak oil, and the end of economic growth in “Ecological Economics Reviews.” Robert Costanza, Karin Limburg & Ida Kubiszewski, Eds. Ann. N.Y. Acad. Sci. 1219: 52-72.

Abstract
Adjusting the economy to the new energy realities of the second half of the age of oil

Our research indicates that, due to the depletion of conventional, and hence cheap, crude oil supplies (i.e., peak oil), increasing the supply of oil in the future would require exploiting lower quality resources (i.e., expensive), and thus will most likely occur only at high prices. This situation creates a system of feedbacks where increasing the oil supply to support economic growth will require high oil prices that will undermine that economic growth. We conclude that the economic growth of the past 40 years is unlikely to continue unless there is some remarkable change in how we manage our economy.
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Murphy, D.J., C.A.S. Hall, and Bobby Powers. 2011. New Perspectives on the Energy Return on Investment of Corn Based Ethanol. Environment, Development and Sustainability, 13(1) pp 179-202.

Abstract
New Perspectives on the Energy Return on (Energy) Investment (EROI) of Corn Ethanol

Research on corn ethanol is overly focused on whether corn ethanol is a net energy yielder, and, consequently, has missed some other fundamental issues, including: 1) whether there is significant error associated with current estimates of the EROI of corn ethanol, 2) whether there is significant spatial variability in the EROI of corn ethanol production, 3) whether yield increases will translate linearly to increases in EROI, 4) the extent to which assumptions about co-product credits impact the EROI of corn ethanol, and 5) how much of the ethanol production from biorefineries is net energy. We address all of these concerns in this research by: 1) performing a meta-error analysis of the calculation of EROI, 2) calculating the EROI for 1287 counties across the U.S., and 3) performing a sensitivity analysis for the values of both yield and co-products within the calculation of EROI. Our results show that the average EROI calculated from the meta-error analysis was 1.07±0.2, meaning that EROI values between 0.80 and 1.20 are statistically inseparable from one. The average EROI calculated across 1287 counties in our spatial analysis was 1.01, indicating that the literature tended to use optimal values for energy inputs and outputs compared to the average conditions across the U.S. Increases in yield had a trivial impact on EROI, while co-product credits had a large impact on EROI. Based on our results from the spatial analysis and the location of biorefineries across the U.S., we conclude that the net energy supplied to society by ethanol is only 0.8% of that supplied from gasoline. Recent work indicates that only energy sources extracted at EROIs of 3:1 or greater have the requisite net energy to sustain the infrastructure of the transportation system of the U.S. In light of this work, we conclude that production of corn ethanol within the U.S. is unsustainable and requires energy subsidies from the larger oil economy. 
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Presentations

Murphy, D.J. Peak Oil and Energy Return on Investment: The End of Economic Growth. 9th Annual Conference of the International Association for the Study of Peak Oil and Gas, Brussels, Belgium. April 27th-29th 2011.

Murphy, D.J. The Energy Return on Investment Threshold and the Growth of Renewable Energy. Annual Conference of the United States Association for the Study of Peak Oil and Gas, Washington, D.C. November 2-5th 2011.

Murphy, D.J. EROI, Insidious Feedbacks, and the End of Economic Growth. Sustainable Use of Renewable Energy (SURE) conference. Syracuse, New York, November 2010.

Murphy, D.J. EROI, Insidious Feedbacks, and the End of Economic Growth. Sixth Annual Conference of the Association for the Study of Peak Oil (ASPO). Washington, D.C. October 2010.

Murphy, D.J. EROI, Insidious Feedbacks, and the End of Economic Growth. MassMutual Financial Group, Actuarial Gathering, Chicopee, MA, September 2010.

Murphy, D.J. EROI, Peak Oil, Alternative Energy, and Economic Growth. Wendell Town Meeting, Wendell, MA, May 2010.

Murphy, D.J. Recent Applications of Energy Return on Investment. Fifth Annual Conference of the Association for the Study of Peak Oil (ASPO). Denver, Colorado. October 2009.

Murphy, D.J. The Relation Between Land-Cover and the Urban Heat Island in Northeastern Puerto Rico. 7th Symposium on the Urban Climate, American Meteorological Society. San Diego, California. September 2007.

Murphy, D.J. Energy Return on Investment: In Theory and Application. 2nd Annual Conference on Biophysical Economics.  Syracuse, New York. October 2009.

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