Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Net energy – a useless, misleading and dangerous metric

09.08.2007
As oil becomes scarce, the world needs new transportation fuels. As new fuel options develop we need means of assessing which are most effective at replacing petroleum.

So far many scientists have used a measure called ‘net energy’. 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.

Instead, Dale recommends comparing fuels by assessing how much petroleum fuel each can replace, or by calculating how much CO2 each produces per km 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 grain 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 gasses compared with petrol, while fibre-produced ethanol gives a 88% reduction compared to petrol.

“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.

Jennifer Beal | alfa
Further information:
http://www.wiley.co.uk

More articles from Ecology, The Environment and Conservation:

nachricht When corals eat plastics
24.05.2018 | Justus-Liebig-Universität Gießen

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>