EROEI Energy Returned On Energy Invested

A more complex (quality corrected) version of the equation is this: "...where is the quality factor for fuel type i at time t and E o and E c are the thermal equivalents of energy outputs and energy inputs, respectively. We construct Divisia indices for energy inputs and outputs to account for energy quality in the numerator and denominator. The prices for energy outputs (oil, natural gas, natural gas liquids) and energy inputs (natural gas, gasoline, distillate fuels, coal, electricity) are the prices paid by industrial end-users for each energy type (US Department of Energy, 1997)." (Aggregation and the role of energy in the economy, Cutler J. Cleveland, Robert K. Kaufmann, David I. Stern, Center for Energy and Environmental Studies and Department of Geography, Boston University, Centre for Resource and Environmental Studies, Australian National University, Canberra, 1999)

An EROEI of 1 means that for every unit of energy you put in, you take 1 unit of usable energy out. An EROEI of greater than 1 means you take more energy out than you put in. For each barrel of oil you extract from the Middle East, you take around 30 times that usable energy back. Or put another way, it costs you approximately the energy of 1 barrel of energy to extract 30 barrels, refine it, move it around the world and pump it into the tank of a vehicle.

You have ~100 barrels in the ground Suppose EROEI is 10 Use 9 barrels Get 90 barrels About 10% waste Suppose EROEI is 1.5 Use 40 barrels Get 60 barrels About 40% waste

No, that’s not right. Look at excel

What are some (approximate) EROEIs? Middle east oil30 Tar sands1.5 Hydro45 Coal25 Nuclear5-20 Wind4-10 Solar4 Corn Ethanolless than 1

EROEI from another WEB site Oil and gas (domestic wellhead) -1940's Discoveries > 's Production 23.0, discoveries 8.0 Coal (mine mouth) 's 's 30.0 Oil shale 0.7 to 13.3 Coal liquefaction 0.5 to 8.2 Geopressured gas1.0 to 5.0 Renewable Ethanol (sugercane) 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 dominated.0 (12.0) -Hot dry rock 1.9 (5.7) to 13.0 (39.0)

Tar Sands ERoEI currently 1.5 Amount in place 1.5 – 1.7 Trillion Barrels Amount recoverable 0.3 – 0.4 Trillion B. Environmental Cost? Cost effective?

Embodied Energy? Traditionally considered, embodied energy is an accounting methodology which aims to find the sum total of the energy necessary - from the raw material extraction, to transport, manufacturing, assembly, installation as well as the marketing and other costs of a specific material - to produce a service or product. (From Wikipedia)

Embodied Energy of an Auto 20 – 90 barrels of oil Higher embodied energy cost for hybrids? CNW’s findings show that the Chevrolet Suburban has an energy cost per mile of $3.134, while a Toyota Prius, the darling of the hybrid crowd, comes in at $ Obviously the Prius can go much farther than the Suburban on a gallon of gasoline, but according to the CNW report, that is only part of the equation, as you must also factor in the energy required to build the vehicle, service it through its lifetime, and recycle its parts at the end.Chevrolet Suburban Toyota Prius As you can guess, the green crowd isn’t taking this news sitting down, and are firing back with their own statistics. But this news kind of confirms the feeling I’ve had toward hybrids from the get-go; they aren’t all they’re cracked up to be. They may save a little on fuel, but not nearly enough to justify the higher sticker price, the higher maintenance costs, and the higher cost to retire them. I’m no bean counter, but I know there is much more to the cost of a vehicle than its mpg figures.

s_of_sustainablity/measures_of_sustainablity_embodied.htm

Conclusions??