The seemingly most reliable information on EROI is quite old and is summarized in chapter 12 of Hall et al. (1986). Newer information tends to fall into the wildly optimistic camp (high EROI, e.g. 10:1 or more, sometimes wildly more) or the extremely pessimistic (low or even negative EROI) camp (Tyner et al. 1998, Tyner 2002, Fleay 2006 and Caldicamp 2006). One recent PhD analysis from Sweden undertook an emergy analysis (a kind of comprehensive energy analysis including all environmental inputs and quality corrections as per Howard Odum) and found an emergy return on emergy invested of 11:1 (with a high quality factor for electricity) but it was not possible to undertake an energy analysis from the data presented (Kindburg, 2007). Nevertheless that final number is similar to many of the older analyses when a quality correction is included. Figure 9. EROI for nuclear power plotted vs. year of analysis. (Source Robert Powers). Click to Enlarge. Tyner was the author (or co-author) on the 1988 and 1997 reports which are examples of the lower EROI numbers -- less than 5:1. Tyner’s 1997 paper reported an “optimistic value” of 3.84 and a “less-optimistic” value of 1.86 and may be based on “pessimistic” cost estimates.