Saturday, December 7, 2013

Working without a net


    I stumbled on a a new energy blogger called the energy skeptic.  Worth a look

    Among other things, the site has lots about ERoEI.  Stuff I hadn't seen before.

    There were a couple of things of note.  First that "net energy" may be more important than Hubbert's  peak.  And that we may cross an important net energy threshold before the peak of oil (all liquids)  production

First the threshold. 

 Here's a review of a 41 page paper by Hall. et al,  in which we find this summary:

Minimum EROI required   Activity
  • 1.1  : 1             Extract oil
  • 1.2  : 1             Refine Oil
  • 3    :  1             Transportation
  • 5    :  1             Grow Food
  • 7-8 :  1             Support Family of Workers
  • 10  :  1             Education
  • 12  :  1             Health Care
  • 14  :  1             Arts and other culture     Source: (Lambert)

  We hit 14:1, we  start to notice that we are living in different world.   We on't have enough " extra energy" to support all the trappings of civilization.      Interestingly,  this threshold may be crossed  before we hit the Hubbert peak..  
Where are we now?
  • The Energy Returned on Investment (EROI) has declined for all fossil fuel resources except coal since the 1950s. In the United States, the EROI of production was 30:1 in the 1970s and less than 10:1 now.  Global EROI has gone from 30:1 in 1995 to around 18:1 in 2006.
Does the US still have a lot of the high EROI stuff?


In the United States, the EROI of production was 30:1 in the 1970s and less than 10:1 now. 

How fast is EROI declining?
   Well, it looks like it dropped from 30:1 to 18:1 in about 20 years.  If I use my calculator correctly, that would be 12 in 20 or .6 per year.  So if it were a straight line (no idea)  - we would hit 14 in 2006+7 = 2013!   Ooops!  
    How would we know if we hit 14:1?    
  • Declining EROI, at the societal level, means that an increasing proportion of energy output is diverted to getting the energy needed to run an economy with less discretionary funds available for “non-essential” projects.
  • The declining EROI of traditional fossil fuel energy sources and this eventual effect on the world economy are likely to result in a myriad of unforeseen consequences.
So, we might see things , like less investment in non energy activities - like infrastructure, police and fire,     And failure to make good on promises made - like Pensions  -.   

What about alternative energy?

  • EROI of renewable energy is very low:
EROI              Source
  • 2:1                 Biofuels are less than 2 to 1, negative or break-even
  • 18:1               Wind (perhaps)
  • 7:1                 Photovoltaic solar
  • Most renewable and nonconventional energy alternatives have substantially lower EROI values than conventional fossil fuels.
I don't like the looks of those numbers.   Hopefully they are wrong.  Here's some pretty detailed  info  from a study of PV in Spain. 

"This is the first time an estimate of Energy Returned on Energy Invested (EROI) of solar Photovoltaics (PV) has been based on real data from the sunniest European country, with accurate measures of generated energy from over 50,000 installations using several years of real-life data from optimized, efficient, multi-megawatt and well oriented facilities.

Prieto and Hall conclude that the EROI of solar photovoltaic is only 2.45, very low despite Spain’s ideal sunny climate.  Germany’s EROI is probably 20 to 33% less (1.6 to 2), due to less sunlight and efficient rooftop installations.

Have nice day!

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