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Appendix
Prices are from the Energy Information Administration Annual Energy Review 2009. Electricity
price is taken as the total US average. Fuel oil price is assumed same as gasoline price. Both capital
expenditures and the value of einvestment = 14 MJ/$2005 for capital, or indirect energy, are taken from
Guilford et al. (2011) of this special issue of Sustainability [18]. The value of MJ/$2005 is calculated
by summing all direct energy divided by the sum of all direct energy expenditures per Equation (9)
when considering multiple direct energy inputs. The “MJ/$2005 for total investment” is the basis for
plotting the modeled price versus EROI in Figures 3 and 4.
Table A1. Prices for oil and natural gas [21] and EROI estimates from [26] and [18].Year (^) ($2005/BBL)US^ oil^ price^ ($2005/Mcf)US^ NG^ price^ (Cleveland,EROI^ Oil^ and 2005)[26]^ Gas^ (GuilfordEROI etOil al.^ and, 2011)[18]^ Gas^
1919 -- ‐‐ 17.13
1939 -- ‐‐ 21.47
1954 17.05 0.61 17.86 23.71
1958 16.61 0.66 18.36 17.82
1963 15 0.83 21.32 19.02
1967 13.83 0.76 22.28 --
1972 12.73 0.71 24.24 19.84
1977 22.7 2.09 15.74 10.81
1982 51.47 4.44 12.56 7.75
1987 23.78 2.58 19.28 14.57
1992 20.89 2.27 21.41 16.63
1997 20.38 2.74 17.60 14.22
2002 24.44 3.2 15.16
2007 62.63 5.88 11.08