• Net Energy List (EROEI) Comparing Different Energy Processes from Energy and the U.S. Economy: A Biophysical Perspective　　http://www.eroei.com/eval/net_energy_list.html

『Summary
　A series of hypotheses is presented about the relation of national energy use to national economic activity (both time series and cross-sectional) which offer a different perspective from standard economics for the assessment of historical and current economic events. The analysis incorporates nearly 100 years of time series data and 3 years of cross-sectional data on 87 sectors of the United States economy. Gross national product, labor productivity, and price levels are all correlated closely with various aspects of energy use, and these correlations are improved when corrections are made for energy quality. A large portion of the apparent increases in U.S. energy efficiency has been due to our ability to expand the relative use of high-quality fuels such as petroleum and electricity, and also to relative shifts in fuel use between sectors of the economy. The concept of energy return on investment is introduced as a major driving force in our economy, and data are provided which show a marked decline in energy return on investment for all our principal fuels in recent decades. Future economic growth will depend largely on the net energy yield of alternative fuel sources, and some standard economic models may need to be modified to account for the biophysical constraints on human economic activity.』

（Introduction）
Statement of hypotheses
Energy and economic production
　Energy costs of capital and labor
　Fuel use and economic output
　Fuel efficiency
Labor productivity and technical change
Energy and inflation
Natural resource quality from an energy perspective
　Alternative fuel sources
Conclusions
References and notes

Table 1. Eastimates of energy return on investment (EROI) ratios for some existing and proposed fuel supply technologies (54). Numbers in parentheses for electricity generation include a quality factor based on a heat rate of 2646 kcal/kWh.

Process		EROI
Nonrenewable
Oil and gas (domestic wellhead)
	1940's	Discoveries＞100.0*
	1970's	Production 23.0, discoveries 8.0
Coal (mine mouth)
	1950's	80.3
	1970's	30.0
Oil shale		0.7 to 13.3
Coal liquefaction		0.5 to 8.2
Geopressured gas		10. to 5.0
Renewable
Ethanol (sugarcane)		0.8 to 1.7
Ethanol (corn)		1.3
Ethanol (corn residues)		0.7 to 1.8
Methanol (wood)		2.6
Solar space heat (fossil backup)
	Flat-plate collector	1.9
	Concentrating collector	1.6
Electricity production†
Coal
	U.S. average	9.0 (27.0)
	Western surface coal
	No scrubbers	6.0 (18.0)
	Scrubbers	2.5 (7.5)
Hydropower		11.2 (33.6)
Nuclear (light-water reactor)		4.0 (12.0)
Solar
	Power satellite	2.0 (6.0)
	Power tower	4.2 (12.6)
	Photovoltaics	1.7 (5.1) to 10.0 (30.0)
Geothermal
	Liquid	4.0 (12.0)
	Hot dry rock	1.9 (5.7) to 13.0 (39.0)
*Based on discovery rates reported by Hubbert (44) and the assumption that energy use in drilling was ;ess than 1 barrel per foot [Hall and Cleveland (44)]. †Does not include energy in fuel.

• （44） W.Davis, Oil Gas J, 56, 105 (1958); M.K.Hubbert, in Hearing Before the U.S. Senate Committee on Interior Insular Affairs (Seris No. 93-40, Government Printing Office, Washington, D.C., 1974); H.W.Menard and G.Sharman, Science, 190, 337 (1975); C.A.S.Hall and C.J.Cleveland, ibid., 211, 576 (1981).
• （45） Oil and gas: C.A.S.Hall, C.J.Cleveland and R.Kaufmann, Biophysical Economics (Wiley, New York, in press) [see also (44)];
  imported petroleum: R.Kaufmann and C.A.S.Hall, in Energy and Ecological Modelling, W.J.Mitsch, R.W. Bosserman and J.M.Klopatek, Eds. (Elsevier, New York, 1981), pp.697-702;
  coal: C.Hall, C.J.Cleveland and M.Berger, ibid., pp.715-724.
  The decline in EROI for coal is due to (i) physical factors such as smaller seam thicknesses and a 1 percent per year decline in the average heat content of bituminous coal from 1955 to the mid-1970's; (ii) a relative increase in surface mining, which is more energy intensive than underground mining, and (iii) the effects on output of the Coal Mine Health and Safety Act of 1969.
• （54） Oil shale: C.G.Lind and W.J.Mitsch, in Energy and Ecological Modelling, W.J.Mitsch, R.W.Bosserman, J.M.Klopatek, Eds.(Elsevier, New York, 1981).
  Coal loquefaction: General Accounting Office, “DOE funds new energy technologies without estimating potential net energy yields” (report to Congress, July 1982).
  Geopressured gas: C.J.Cleveland and R.Costanza, Energy, 9, 35 (1984).
  Ethanol from sugarcane: C.S.Hopkinson,Jr. and J.W.Day,Jr., Science, 207, 302 (1980).
  Ethanol from corn: R.S.Chambers, R.A.Herendeen, J.J.Joyce and P.S.Penner, ibid., 206, 789 (1979).
  Ethanol from corn residues: D.Pimentel et al., ibid., 212, 1110 (1981).
  Ethanol from wood: B.Hannon and H.Perez-Blanco, “Ethanol and methanol as industrial feedstocks,” report to Argonne National Laboratories, Argonne, IIi., contract ANL 31-109-38-5154 (1979).
  Residential solar: B.Hannpn, in Energy, Economics, and the Environment, H.E.Daly and A.F.Umana, Eds. (westview, Boulder, Colo., 1981).
  Electricity Production: U.S. average: D.Pilati, Energy, 2, 1 (January 1977); western surface coal: P.Penner, J.Kurish, and B.Hannon, “Energy and labor cost of coal electric fuel cycles” (Document 273, Energy Research Group, University of Illinois, Urbana, 1979);
  Hydropower: M.W.Gilliland, J.M.Klopatek and S.G.Hildebrand, Net Energy of Seven Small-Scale Hydroelectric Power Plants (Oak Ridge National Laboratory, Oak Ridge, Tenn., 1981);
  Power satellite: R.A.Herendeen, T.Kary and J.Rebitzer, Science, 205, 451 (1979);
  Power tower: A.J.Frabetti, “A study to develop estimates of merit for selected fuel technologies” (Development Sciences, Inc., East Sandwich, Mass., 1975);
  Photovoltaics (low estimate): D.Grimmer, “ Solar energy breeders” (Report LA-UR-78-2973, Los Alamos Scientific Laboratory, Los Alamos, N.M., 1978), quoted in Hannon, op. cit.;
  Geothermal: R.Herendeen and R.Plant, “Energy analysis of geothermal electric system” (Document 272, Energy Research Group, University of Illinois, Urbana,1979).
  See C.A.S.Hall et al. (45) and R.Kaufmann and C.A.S.Gall (45) for nuclear and other solar estimates.