Ideal EROI (energy return on investment) deepens the understanding of energy systems

This article presents a new EROI (energy return on investment) factor named the ideal EROI, or EROIide, that provides the theoretical upper boundary of the EROI of a given system. The EROIide is the ratio between the inputs within the EROIstnd boundaries and the theoretical maximum output from a given system; i.e, all losses are omitted and the maximum theoretical energy output of the system is used. EROIide resembles the concept of the idealised Carnot heat engine. Although the EROI of a given system can never be equal to EROIide, the EROIide can be used to estimate the potential for improvement; e.g., if the difference between the EROIide and EROIstnd is small then little improvement can be expected from further research funding. Calculations using EROIide can add a valuable depth to the overall results of an EROI study, benefitting policy makers involved in energy policy planning. Three application examples of EROIide are provided, one for a hydroelectric power plant, one for a geothermal power plant and one example for a hypothetical wind farm. The calculations show that the hydro power plant could improve approximately 3 fold, whereas the geothermal plant had a potential of 27 fold improvement over its lifetime.

[1]  D. Pauly,et al.  Fueling Global Fishing Fleets , 2005, Ambio.

[2]  Liselotte Schleisner,et al.  Life cycle assessment of a wind farm and related externalities , 2000 .

[3]  Runar Unnthorsson,et al.  Energy return on investment of hydroelectric power generation calculated using a standardised methodology , 2014 .

[4]  Daniel Weißbach,et al.  Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants , 2013 .

[5]  K. Mulder,et al.  Energy Return on Investment: Toward a Consistent Framework , 2008, Ambio.

[6]  Runar Unnthorsson,et al.  Hot water production improves the energy return on investment of geothermal power plants , 2013 .

[7]  C. Cleveland Net energy from the extraction of oil and gas in the United States , 2005 .

[8]  Andrés Feijóo,et al.  Wind power distributions: A review of their applications , 2010 .

[9]  G. Boyle Renewable Energy: Power for a Sustainable Future , 2012 .

[10]  J L Gordon Hydraulic turbine efficiency , 2001 .

[11]  Charles A. S. Hall,et al.  What is the Minimum EROI that a Sustainable Society Must Have , 2009 .

[12]  Henrik Lund,et al.  Renewable energy strategies for sustainable development , 2007 .

[13]  Joan Martinez-Alier,et al.  The EROI of agriculture and its use by the Via Campesina , 2011 .

[14]  N. Pelletier,et al.  Feeding farmed salmon: Is organic better? , 2007 .

[15]  David J. Murphy,et al.  Order from Chaos: A Preliminary Protocol for Determining the EROI of Fuels , 2011 .

[16]  Charles A. S. Hall Introduction to Special Issue on New Studies in EROI (Energy Return on Investment) , 2011 .