Biofuel is, too, a laughing gas matter

Life Cycle of Bio-Energy


Counter to other, alternative fuel analysis, Crutzen and colleagues question whether growing and burning many biofuel crops actually may raise, rather than lower, greenhouse gas emissions.

Alpha Galileo1 reports on a new study by Paul Crutzen. Best known for his Nobel prize winning work on the study of the ozone layer, Crutzen and colleagues have calculated that the amounts of nitrous oxides released by growing some of the most commonly used biofuel crops is around twice the amount previously thought – “wiping out any benefits from not using fossil fuels and, worse, probably contributing to global warming.”

For rapeseed biodiesel, which accounts for about 80 per cent of the biofuel production in Europe, the relative warming due to nitrous oxide emissions is estimated at 1 to 1.7 times larger than the relative cooling effect due to saved fossil CO2 emissions. For corn bioethanol, dominant in the US, the figure is 0.9 to 1.5. Only cane sugar bioethanol – with a relative warming of 0.5 to 0.9 – looks like a better alternative to conventional fuels.

This blog previously observed, with so much ongoing funding for biofuels, that it is a bit difficult to find scientific study in Europe or North America that questions the push for alternative fuels. The study of N2O release from agro-biofuel production by Crutzen, et al, which is currently subject to open review in the journal Atmospheric Chemistry and Physics, thus is important because it critiques the current wisdom of European policy to set standards for the use of biodiesel.

Biodiesel and Diesel Pumps


Crutzen’s work highlights the importance of establishing correct full life-cycle assessments for biofuels.

The U.S. Department of Energy and the U.S. Department of Agriculture had published the results of a three-and-a-half-year study, Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus (PDF)2, which was to provide a comprehensive “cradle to grave” environmental comparison of the two fuels in order to compare the total “life cycle” costs and benefits of each. The life cycle inventory considered energy resources consumed during production, manufacture, transportation and distribution.

The total fossil energy efficiency ratio used in the study was total fuel energy / total fossil energy used. Since biodiesel and petroleum diesel have very similar energy value, the study showed that biodiesel had an energy efficiency four times greater than that of petroleum diesel. It also demonstrated an advantage over ethanol, because the energy value of ethanol is about three-quarters the energy value of petrol.

The DOE / USDA study also examined air, water and solid waste emissions generated by petroleum diesel fuel and biodiesel. While the biodiesel lif cycle inventory included a consideration of NOx emissions, it focused on the reduction accomplished by blending over 100% RME (rapeseed methyl ester) during combustion.

Soil
The unconsolidated mineral matter on the surface of the Earth that has been subjected to and influenced by genetic and environmental factors of parent material, climate, macro- and microorganisms, and topography, all acting over a period of time and producing a product that differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.
Nitrous Oxide Concentration


The level of N2O emissions is one indicator of the human influence on the atmosphere during the Industrial Era, i.e., the increasing concentration of nitrous oxide is anthropogenic.

Microbes convert much more of the nitrogen in fertilizer to nitrous oxide than previously thought – 3 to 5 per cent, according to Crutzen and colleagues. Their results contradict “the widely accepted figure of 2 per cent used by the International Panel on Climate Change (IPCC) to calculate the impact of fertilizers on climate change.”

As release of N2O affects climate and stratospheric ozone chemistry by the production of biofuels, much more research on the sources of N2O and the nitrogen cycle is urgently needed…Here we concentrated on the climate effects due only to required N fertilization in biomass production and we have shown that, depending on N content, the use of several agricultural crops for energy production can readily lead to N2O emissions large enough to cause climate warming instead of cooling by “saved fossil CO2”. What we have discussed is one important step in a life cycle analysis, i.e. the emissions of N2O, which must be considered in addition to the fossil fuel input and co-production of useful chemicals in biofuel production.

We have also shown that the replacement of fossil fuels by biofuels may not bring the intended climate cooling due to the accompanying emissions of N2O. There are also other factors to consider in connection with the introduction of biofuels. We have not yet considered the extent to which the high percentage of N-fertilizer which is not taken up by the plants, and the organic nitrogen in the harvested plant material, may stimulate CO2 uptake from the atmosphere; estimates for this effect are very uncertain. We conclude, however, that the relatively large emission of N2O exacerbates the already huge challenge of getting global warming under control.

Some of the GCC discussion focused upon the need for materials manufacturing as well as fuel. Still most of the commentary focused on biofuel production and GHG emissions by the agriculture sector.

GCC commentator Jim G. asked some incisive, albeit rhetorical, questions:

  • Isn’t it true according to the above that, for levels of nitrogen oxides to be greater tomorrow than they are today, we’ll have to either use more nitrogen compounds per acre on existing farmland, or boost the quantity of farmland under cultivation?
  • Assuming boosting the quantity of land under cultivation is more likely, biofuels can only be deemed a significant cause of trouble if they take up a significant quantity of that land.

    But then there’s the “food versus fuel” argument, standing in contradiction to this, i.e., the claim that there is a limited quantity of arable land, and that more biofuels will result in less food.

    So if we had 50% biofuels use on arable land under cultivation, and we decided to stop doing so because it produced nitrogen oxides, would we instead let the land lie fallow again? Probably not. And then our nitrogen problems are the same as they were. So if there is a zero-sum relationship between food and fuels, it seems to be that’s a much more serious problem.

  • But if, as pointed out by others, second generation feedstock require no fertilizers, this latter threat diminishes significantly.

    Does anyone know if net land under cultivation increases over time as food demand increases? This certainly isn’t true in the USA, but it could be true globally, no?

Ethanol Scam


“So, not to worry. Biofuels will not be derailed, just slowed to sustainable level of growth.”

So, is “sustainability” the new, Big Farm catchphrase, like democracy is for Big Oil?

Pursuant to a previous reference by Green Car Congress3 to a UN Report, i.e., the livestock sector generates more GHG emissions than the transport sector, GCC commentator Andrey provides a comprehensive summary of concerns about GHG emissions from the agriculture sector:

Agriculture emits much more GHG than combustion of fossil fuels, it is well researched and well downplayed fact. To put numbers into perspective, just released research estimates CO2 emissions from human respiration being 0.6 GT carbon per year, domesticated animals respiration releases 1.5 GTC, plus 1 GTC from decomposition of human and domesticated animals waste; total 3.1 GTC per year. Compare it to 7 GTC emitted by combustion of fossil fuels. Presented numbers do not include huge emissions of methane from domesticated animals farting and belching (regular cow emits close to 600 liters of methane daily), and emissions of GHG associated with growing food for humans and feed for animals.

Politicians do not really give a hood about it. Initial intentions to address GW readily deteriorated into meaningless campaign to tax emissions of CO2 from fossil fuel combustion – no more no less. Examples are plenty:

GHG emissions of New Zealand cattle (farting & belching!) accounts for 60% of total country GHG emissions, and NZ addressed the issue by imposing this week cup™ system on emission of CO2 from fossil fuel combustion;

Diesel engines contribute to warming more than comparable gasoline engines (due to emissions of Black Carbon –diesel soot, which is very potent heating agent), but European politicians prefer to overlook it and promote diesel proliferation to reduce their addiction to Middle East oil.

Russian natural gas supplied to Europe emits more GHG than, say, use of Polish coal (due to no less than 5% of NG venting in Russia NG industry; NG (methane) is 23+ times more potent GHG than CO2), yet Europe increases import of this clean-burning and convenient HC fuel.

Same with US corn ethanol. It barely has positive EROI, and considering that distillation is almost universally is fueled by coal, and taking into account N2O and soil organic decomposition CO2 emissions during corn growing, corn ethanol is substantial net contributor to GW.

It just happened that corn ethanol is extremely beneficial from other points of view: good PR, reduction of oil import, best invented way to subsidize rural America, good leverage to keep corn prices from periodic collapses, improved food security (25% of corn harvest used to produce corn ethanol in US could be easily switched to food&feed in case of emergency).

My estimations are that corn ethanol in US will reach about 10% of current US gasoline consumption by volume, substituting up to 5% of crude oil demand. Further increase will be slow, but steady: increased corn yields, optimized to fuel production corn hybrids, GM yeasts, cellulosic ethanol, etc. This number will be much higher for Brasil, and much lower for Europe.

Continue reading here: Black Liquor to dimethyl ether

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