is WAY too low. And 0.8 too high for oil except space heating. R is raw energy in. C is energy out to the consumer. It is also the control ratio, C/R in feedback theory. Consider that our system is a simple feedback loop with increasing EROI acting as negative feedback. Would dropping EROI cause instability? It seems unlikely as our current system is incredibly wasteful in energy. Usually negative feedback justs slows things down rather than sending them spinning out of control. Of course, our system is much more complex than that which again shows that EROEI is too simplistic to be useful as well as outright wrong. The different lines are for different transformational(thermal) efficiencies to go from raw energy to a consumer fuel. Going from crude oil to gasoline is about 80% efficient. Going from coal to electricity is 30% efficient. The result here shows that highly transformationally efficient energy sources are more affected by dropping EROI. CCGT can get 50% efficiency which helps offset high natural gas prices but that just encourages the quick depletion of natural gas. CHP in Denmark was adopted after 1973 when oil was phased out. Denmark's ten major cities have city-wide district heating schemes where most of the heat (95%-98%) is produced in large coal- or gas-fired CHP plants and waste incineration CHP plants. All extra costs, investment and operating costs, as well as lost electricity production , have been paid by the heat consumers, who in turn have gained most