Land Use Changes Are Main Factor In Carbon Emissions From Biofuels.

Not all biofuels are "green" according to where the crops from which they are derived are grown. The worst offenders are palm oils which may have ten times the carbon emissions of normal diesel fuel derived from petroleum, if the palm is grown on converted rainforest land. In contrast, when the palm is grown on previously cleared land, its emissions are around one fifth that for conventional petroleum-derived diesel. These conclusions are from a life-cycle analysis of 14 different source-fuels made by a team at M.I.T. which takes account of the carbon emissions incurred in the growing and harvesting of the crop, including land-clearance, its processing and the CO2 that results from final combustion of the fuel. http://pubs.acs.org/doi/abs/10.1021/es102597f?journalCode=esthag

Accordingly, it is suggested that biofuels that depend far less on changes in land use may be the cleanest in terms of carbon emissions, including those from salicornia and algae. The latter particularly require smaller areas of land to produce them than their equivalent quantity derived from land-based crops, and the fertility of that land is not an issue, since they can be grown in tanks or biorectors placed on land of any quality.

Certainly, greenhouse gas emissions are not the only consideration to be borne in mind in choosing a particular biofuel, and there is the matter of production-costs and the feasibility of making the fuel on the large scale, if any significant substitution for petroleum-derived fuels is to prove practical. In the evaluation of diesel from algae given in the M.I.T. paper, is given a considerable range (0.1 - 2.1) as normalised to conventional diesel, i.e. algal fuel is reckoned as between one tenth to more than twice as carbon-emitting as petro-diesel depending on details of the processing. What is interesting is that the conversions of biomass (e.g. switchgrass and salicornia) to synthetic diesel using Fischer-Tropsch (F-T.) and coal to liquids with F.-T. generally appear favourable in comparison with standard petro-diesel production.

I am grateful to Dr Jim Hileman for sending me a copy of the paper.

British Government Faces Up To Peak Oil.

The UK Secretary for Energy and Climate Change, Chris Huhne, has committed to establish an "Oil Shock Response Plan" to cope with some of the consequences of peak oil (http://www.businessgreen.com/bg/news/2072738/exclusive-government-develop-oil-shock-response-plan). While there remains dissent as to the facts of peak oil, a growing body of experts think that the phenomenon will occur at some point during the next five years. On a recent BBC radio 4 broadcast (March 27th) a former president of Shell, John Hofmeister, reckoned that there was no problem with the production of oil meeting demand for it until 2050/2060. This kind of estimate includes various kinds of unconventional oil for which the EROEI (Energy Returned on Energy Invested) is far lower than for the cheap readily available conventional oil on which the modern global world depends.

Specifically, there are reckoned to be 1.2 trillion barrels of conventional oil and another 3.7 trillion barrels of unconventional oil, which includes oil-shale and tar-sands. Neither of these resources contain "oil" as such, but kerogen and bitumen, respectively, which need to be processed into fuel using substantial amounts of energy and water. By way of comparison, the EROEI for conventional oil is reckoned at somewhere between 11 and 18 (it was 100 for the original Texan "gushers") while it is around 3 for these unconventional sources. The Hirsch report, published in 2005, concluded that to avoid major disruptions, we need to plan 20 years before the arrival of the oil peak, and that we just don't have.

While details of the British plan are yet to be disclosed, it is said that consideration would be made of how to protect the UK economy "if we knew that the oil price would soar to $250 in 2014." This follows Huhne's previous mandate to "wean Britain off oil" by introducing thousands of electric car charging points. It remains less clear where the electricity will come from, other than from fossil fuels (http://blogs.forbes.com/energysource/2011/04/07/the-heretic-electric-cars-should-be-called-coal-cars/), or how long it will take and what material resource challenges will be manifested in the manufacture of sufficient electric cars to substantially supplant the 30 million cars on British roads.

Fracking Does Contaminate Groundwater With Methane, But Jury Still Out On Process Overall.

A study has been undertaken by Duke University of methane levels in water from 68 private wells above the Marcellus and Utica shales in Pennsylvania and New York. The details have just been published in the Proceedings of the National Academy of Sciences http://www.pnas.org/content/early/2011/05/02/1100682108.full.pdf+html. Of these, around one third were in an "active extraction area", which by definition is within one kilometre of a gas well, the remainder being more distant.

The results of the study are striking: in all but one case, making 15 altogether, it is only within 800 metres of a gas-well that levels of methane are high enough (10 - 28 mg/L) to merit warning of the occupants and prudent remediation down to levels ; 10 mg/L, according to the US Office of the Interior, or above 28 mg/L at which point "potentially explosive or flammable quantities of the gas are being liberated in the well and/or may be liberated in confined areas of the home," which requires immediate mitigation. http://arblast.osmre.gov/downloads/Mine%20Gases%20and%20Dust/FINAL-Methane.pdf

In this particular study, no evidence for fracking fluid finding its way into the groundwater was found nor for intrusion from deep saline brines into aquifers closer to the surface. According to an isotopic analysis, the excess methane is consistent as originating from deeper thermogenic sediments, rather than being produced biologically in near surface environments.

The Energy Institute at the University of Texas is set to conduct the first integrated study of the science, policy and environmental issues surrounding hydraulic fracturing to recover shale gas at a cost of $300,000, with preliminary findings expected to be released in October. This project aims to combine an independent assessment of groundwater contamination, fugitive air emissions and seismic events for which fracking has been blamed in shale formations, and to evaluate the effectiveness of legal regulations attendant to the process, focussing on Barnett Shale, which extends under over 20 counties in North Texas . The Environmental Protection Agency is conducting its own investigation with results expected after the end of the year 2012.

The overall conclusions of these studies could not be more crucial to future US energy provision. Production of shale-gas was 2.02 trillion cubic feet (Tcf) in 2008: a 71% increase over the previous year, which in 2009 grew 54% to 3.11 Tcf. Proven US shale reserves at the end of 2009 were observed to increase by 76% to 60.6 Tcf. In its Annual Energy Outlook for 2011, the US Energy Information Administration (EIA) more than doubled its estimate of technically recoverable shale-gas reserves to 827 Tcf from 353 Tcf, by including exploration data taken from new fields such as the Marcellus, Haynesville and Eagle Ford shales. It is estimated that shale-gas production will increase from 14% of total US natural gas production in 2009 to 45% by 2035. But this of course depends on whether the process of hydraulic fracking is proved sufficiently safe to be so widely adopted.

Deep Oil From Diamonds.

According to a new computer model, liquid methane in contact with a partially hydrogen-terminated diamond surface at extremely high pressures and temperatures spontaneously forms longer hydrocarbons, and hence the material of crude oil could be formed deep in the earth. Geologists, certainly in the West, believe that 99% or more of the hydrocarbons present in crude oil and natural gas originate from the "cooking" over millennia of the dead remains of living organisms (biotic), buried under layers of sediments 5-10 miles deep in the Earth's crust. However, the abiotic theory of petroleum generation found force in Russia and Ukraine, proposed by such greats as Dmitri Mendeleev (who devised the Periodic Table the classifies the chemical elements), Alexander von Humboldt and Marcellin Berthelot.

The authors of the present study (http://www.pnas.org/content/108/17/6843.full.pdf+html) do not claim to have proved a case for abiotic oil, but they note that hydrocarbons could be formed by purely mineral means in particular geological environments such as rifts and subduction zones where the temperatures and pressures are "right", i.e. 1,500 K and 50,000 times the pressure at the surface of the Earth. The calculations indicate that the formation of longer chain hydrocarbons can happen in pure methane but the process is accelerated when the methane molecules are in contact with metal or carbon surfaces, e.g. diamond which act as catalysts for the methane-polymerisation to occur.

Fascinating of course, and undoubtedly these results will be taken in some quarters to mean that we will never run out of oil, Peak Oil being bunkum. But even if there were proven to be vast underground lakes of hydrocarbons, if we cannot recover them fast enough to begin matching the current 30 billion barrels/year of contemporary use and rising, it makes no difference. We should not be thrown any red-herrings that we need not press-on toward a future that is far less dependent on oil, and indeed a better planned use of energy in all its forms.

Green Alternatives to Rare Earth Elements?

Always ready to air the other side of an argument, I return to the matter of whether Rare Earth Elements (REEs) and their impending scarcity are the Achilles heel of green energy. Since writing about this and the Chinese monopoly on cheap(ish) REEs on this blog, and my columns on Forbes and on Scitizen, I have become aware of countering polemics that e.g. wind-turbines, hybrid cars and low energy lighting does not depend absolutely on them. This indeed is true, at least in an absolute sense. The majority of current wind turbines don't use REE-based permanent magnets, while electric cars — such as the Tesla Roadster — can run on induction motors that don’t require them either.

The power generated by a wind turbine is directly proportional to the sweep area of the blades and the cube of wind-speed. As the generating power of wind-turbine units increases, so does the dimension of the apparatus to provide it, hence a blade span of 124 metres is required for some 5 MW units, with a unit height of 114 metres.

The use of permanent magnet generators eliminates the need for gear boxes, and can be accomplished with the application of Neodymium-Iron-Boron REE magnets, known as "Neo-magnets". These designs increase mechanical efficiency and reliability, and reduce the internal energy losses in the machines. However, some of the larger units, say 5 MW rated capacity, might require a tonne or more of neodymium. I am aware that ferrite magnets can be used instead of REEs, but my understanding is that weight for weight they are less powerful by a factor of about ten than REE magnets requiring heavier engineering of the wind-power unit to support them. The matter may not be so straightforward however, according to the following written by an experienced engineer in the magnet/wind-power field (http://www.usmagneticmaterials.com/documents/HarvestingWind.pdf):

"One might think that on a pound-for-pound basis, permanent magnet generator using sintered NdFeB will provide the highest energy-conversion efficiency, but this is not necessarily true. In
order to optimize the generator efficiency over a wide speed range, it is best to have some control over the amount of magnetic flux in the circuit, so that the flux can be weakened at higher wind speeds. Sintered NdFeB, with its extremely high flux density and high coercivity, is quite “permanent.” At high speeds, this “permanence” can saturate the generator with flux, leading to greatly increased iron losses. Also, sintered NdFeB is electrically conductive, causing eddy current losses and inductive heating in the magnets.

At higher wind speeds, these parasitic losses increasingly eat into the efficiency and heat up the generator, causing a rapid degradation in performance. Non-conductive sintered ferrite magnets are better in this regard, providing a bit more efficiency headroom at higher speeds. Though the energy product of sintered NdFeB is roughly 10 times that of sintered ferrite, the cost per kilogram of sintered NdFeB is 30 times that of ferrite. The higher cost of NdFeB provides, at best, an incremental gain in overall system efficiency, and I believe that sintered ferrite can provide the best return on investment for a permanent magnet wind turbine generator. There are many interesting magnetic circuit topologies and control schemes that provide flux weakening at higher speeds, thereby increasing the overall system efficiency.

With continuing advances in power electronics and control algorithms, these designs emphasize the “electro” part of the generator with copper and steel, at the expense of the “magnet” part. Several clever generator designs employ lower-energy permanent magnets, such as injection-molded ferrite, to boost the output of what would typically be a non-permanent- magnet machine. These “hybrid magnetic circuit” designs can produce the highest efficiency over the widest speed range, providing the best long-term bang for the buck in a wind turbine system. The cost of such generators is driven by the cost of power electronics and controls, more so than the permanent magnets, wire and steel."

It seems to me that there are definite advantages to using REEs, and there is a move to having 25% of wind-power generation from units containing Neo-magnets by 2015. But since it seems clear that providing sufficient REEs to fill the hole dug by demand for this technology is unlikely, finding an alternative path to such renewable energy is critical. Most of the ongoing efforts to do so are at the "research level" and so having actual wind-devices generating significant green-electricity as fossil-fuel power declines is years away. Even were there no problem over resources or choice of technology, there is a distinct lack of manufacturing capacity for wind energy, certainly on the scale of demand to meet UK "green energy" targets set by the European Commission. It is the perennial rate of flow, conversion or recovery that limits the inauguration of all new technology.