Buenos Aires based ABATEC SA announces the release of a line of small biodiesel plants with modular design, high temperature reaction for the best yield, to produce from 50 to 1000 gal/day (190 to 3785 liter/day) of high quality methylester and valuable glycerol.
Expert: 'net energy' - a useless, misleading and dangerous metric
Even though we often use the concept of the energy balance of fuels to compare different biofuels, taking this metric of 'net energy' further for comparisons with other transport and energy options is not a good idea according to an expert. Years ago, a Biopact member came to the same conclusion, criticizing the value of the concept, which is profusely used in a wholly unscientific way by some environmentalists, peak oil 'analysts' and journalists alike.
As new fuel options develop we need means of assessing which are most effective at replacing petroleum, - on this most of us would agree. So far many have used the measure called ‘net energy’, often to argue against biofuels. However, Professor Bruce Dale from Michigan State University claims, "Net energy analysis is simple and has great intuitive appeal, but it is also dead wrong and dangerously misleading – net energy must be eliminated from our discourse." Dale’s perspective is published in the first edition of Biofuels, Bioproducts and Biorefining, which was recently launched to make the debate on the nascent bioeconomy more scientific and rigorous.
In his article titled "Thinking clearly about biofuels: ending the irrelevant net energy debate and developing better performance metrics for alternative fuels" professor Dale recommends comparing fuels by assessing how much petroleum fuel each can replace, or by calculating how much CO2 each produces per kilometer driven.
A fuel’s 'net energy' is calculated by attempting to assess how much energy a new fuel supplies, and then subtracting the energy supplied by fossil fuels needed to create the new fuel. The calculation is often carried out in a way that leaves corn ethanol with a net energy of -29%, giving the impression that it uses more fossil fuels to produce it that the new fuel supplies. Dale claims that this figure is then used by opponents of biofuels to pour scorn on the new products.
The problem with net energy, says Dale, is that it makes an assumption that all sources of energy (oil, coal, gas etc) have equal value. "This assumption is completely wrong – all energy sources are not equal – one unit of energy from petrol is much more useful than the same amount of energy in coal, and that makes petrol much more valuable," says Dale.
For evidence, he points to the markets, where a unit of energy from gas, petrol and electricity are worth 3.5, 5 and 12 times as much as a unit of energy from coal, respectively.
"Clear thinking shows that we value the services that energy can perform, not the energy per se, so it would be better to compare fuels by the services that each provides... not on a straight energy basis, which is likely to be irrelevant and misleading," says Dale.
For example, biofuels could be rated on how much petroleum use they can displace or their greenhouse gas production compared with petroleum. His calculations indicate that every MJ of ethanol can displace 28 MJ of petroleum, in other words ethanol greatly extends our existing supplies of petroleum. Using corn ethanol provides an 18% reduction in greenhouse gases compared with petrol, while sugarcane based ethanol gives an 80% reduction and cellulosic ethanol is expected to yield an 88% reduction compared to petrol:
energy :: sustainability :: ethanol :: biodiesel :: biomass :: bioenergy :: biofuels :: energy balance :: net energy :: science ::
“As we embark on this brave new world of alternative fuels we need to develop metrics that provide proper and useful comparisons, rather than simply using analyses that are simple and intuitively appealing, but give either no meaningful information, or worse still, information that misleads us and misdirects our efforts to develop petroleum replacements,” says Dale.
Note that several years ago, a Biopact member made a similar argumentation saying that the concept of 'net energy' (EROEI - energy returned on energy invested) may be useful for comparisons of one particular biofuel with another, provided clear system parameters and boundaries are defined, but that beyond such comparisons, the concept becomes wholly inadequate. EROEI says nothing about the complex social, economic and environmental services of different energy, transport and fuel production concepts.
Moreover, 'net energy' calculations have no fixed starting and end point, they suffer under poorly defined 'horizons' and can be extended indefinitely to become absurd. For example, debates went so far as to ask whether, in a calculation of the EROEI for oil, the energy spent on food consumed by oil exploration workers had to be factored in (for biofuels, some argue that you should include energy inputs in the laborers who harvest, e.g. jatropha seeds); or that the energy needed to produce the cotton used in the clothes of Siberian oil drillers needed to be taken into account; for wind power, do you need to factor in the energy put into cleaning up the copper mining sites where the copper used in the turbine is mined? Do you need to take a generic type of copper? Or do you factor in the energy needed to protect the copper mines in Congo, where the UN has its largest peace-keeping force, which, in turn, spends huge amounts of energy on doing its job? Clearly, this is problematic.
EROEI can be used to compare different biofuels produced in relatively similar ways, when comparable boundaries are set for the production steps of each fuel, at the beginning of the calculus. Using the concept to make comparisons of entirely different energy systems, is often not possible.
Back then, his criticism infuriated some members of the Peak Oil community, who often (ab)use the concept of EROEI to make a case against all alternatives to the petroleum based economy. They do so to push an unnecessary, apocalyptic message of doom and global societal collapse, which stiffles all attempts to create a new future. Obviously, not all people involved in studying the decline of oil resources are that fanatic, but the EROEI concept keeps getting used in unscientific ways by many people, including environmentalists, journalists and Peak Oil amateurs.
References:
Bruce E. Dale, "Thinking clearly about biofuels: ending the irrelevant net energy debate and developing better performance metrics for alternative fuels", Biofuels, Bioproducts and Biorefining, Volume 1, Issue 1, September 2007, DOI: 10.1002/bbb.5
Eurekalert: Net energy - a useless, misleading and dangerous metric, says expert - August 9, 2007.
As new fuel options develop we need means of assessing which are most effective at replacing petroleum, - on this most of us would agree. So far many have used the measure called ‘net energy’, often to argue against biofuels. However, Professor Bruce Dale from Michigan State University claims, "Net energy analysis is simple and has great intuitive appeal, but it is also dead wrong and dangerously misleading – net energy must be eliminated from our discourse." Dale’s perspective is published in the first edition of Biofuels, Bioproducts and Biorefining, which was recently launched to make the debate on the nascent bioeconomy more scientific and rigorous.
In his article titled "Thinking clearly about biofuels: ending the irrelevant net energy debate and developing better performance metrics for alternative fuels" professor Dale recommends comparing fuels by assessing how much petroleum fuel each can replace, or by calculating how much CO2 each produces per kilometer driven.
A fuel’s 'net energy' is calculated by attempting to assess how much energy a new fuel supplies, and then subtracting the energy supplied by fossil fuels needed to create the new fuel. The calculation is often carried out in a way that leaves corn ethanol with a net energy of -29%, giving the impression that it uses more fossil fuels to produce it that the new fuel supplies. Dale claims that this figure is then used by opponents of biofuels to pour scorn on the new products.
The problem with net energy, says Dale, is that it makes an assumption that all sources of energy (oil, coal, gas etc) have equal value. "This assumption is completely wrong – all energy sources are not equal – one unit of energy from petrol is much more useful than the same amount of energy in coal, and that makes petrol much more valuable," says Dale.
For evidence, he points to the markets, where a unit of energy from gas, petrol and electricity are worth 3.5, 5 and 12 times as much as a unit of energy from coal, respectively.
"Clear thinking shows that we value the services that energy can perform, not the energy per se, so it would be better to compare fuels by the services that each provides... not on a straight energy basis, which is likely to be irrelevant and misleading," says Dale.
For example, biofuels could be rated on how much petroleum use they can displace or their greenhouse gas production compared with petroleum. His calculations indicate that every MJ of ethanol can displace 28 MJ of petroleum, in other words ethanol greatly extends our existing supplies of petroleum. Using corn ethanol provides an 18% reduction in greenhouse gases compared with petrol, while sugarcane based ethanol gives an 80% reduction and cellulosic ethanol is expected to yield an 88% reduction compared to petrol:
energy :: sustainability :: ethanol :: biodiesel :: biomass :: bioenergy :: biofuels :: energy balance :: net energy :: science :: “As we embark on this brave new world of alternative fuels we need to develop metrics that provide proper and useful comparisons, rather than simply using analyses that are simple and intuitively appealing, but give either no meaningful information, or worse still, information that misleads us and misdirects our efforts to develop petroleum replacements,” says Dale.
Note that several years ago, a Biopact member made a similar argumentation saying that the concept of 'net energy' (EROEI - energy returned on energy invested) may be useful for comparisons of one particular biofuel with another, provided clear system parameters and boundaries are defined, but that beyond such comparisons, the concept becomes wholly inadequate. EROEI says nothing about the complex social, economic and environmental services of different energy, transport and fuel production concepts.
Moreover, 'net energy' calculations have no fixed starting and end point, they suffer under poorly defined 'horizons' and can be extended indefinitely to become absurd. For example, debates went so far as to ask whether, in a calculation of the EROEI for oil, the energy spent on food consumed by oil exploration workers had to be factored in (for biofuels, some argue that you should include energy inputs in the laborers who harvest, e.g. jatropha seeds); or that the energy needed to produce the cotton used in the clothes of Siberian oil drillers needed to be taken into account; for wind power, do you need to factor in the energy put into cleaning up the copper mining sites where the copper used in the turbine is mined? Do you need to take a generic type of copper? Or do you factor in the energy needed to protect the copper mines in Congo, where the UN has its largest peace-keeping force, which, in turn, spends huge amounts of energy on doing its job? Clearly, this is problematic.
EROEI can be used to compare different biofuels produced in relatively similar ways, when comparable boundaries are set for the production steps of each fuel, at the beginning of the calculus. Using the concept to make comparisons of entirely different energy systems, is often not possible.
Back then, his criticism infuriated some members of the Peak Oil community, who often (ab)use the concept of EROEI to make a case against all alternatives to the petroleum based economy. They do so to push an unnecessary, apocalyptic message of doom and global societal collapse, which stiffles all attempts to create a new future. Obviously, not all people involved in studying the decline of oil resources are that fanatic, but the EROEI concept keeps getting used in unscientific ways by many people, including environmentalists, journalists and Peak Oil amateurs.
References:
Bruce E. Dale, "Thinking clearly about biofuels: ending the irrelevant net energy debate and developing better performance metrics for alternative fuels", Biofuels, Bioproducts and Biorefining, Volume 1, Issue 1, September 2007, DOI: 10.1002/bbb.5
Eurekalert: Net energy - a useless, misleading and dangerous metric, says expert - August 9, 2007.
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