Energy Sources
Energy Sources
Nanomaterials Are Prey To EU Ministers
Jul 14th
In his 2002 novel “Prey,” the late Michael Crichton advanced a fictional scenario in which nanoparticles escaped from a lab and formed swarms in the desert with the drive and ability to kill humans and other animals whom they could use as feeding-templates on which bacteria could grow to replicate more of their kind. While such a scenario does appear alarmist and unlikely in reality, there remains nonetheless a sense of disquiet over the safety of nanomaterials, and their potential toxicity should they be released into the environment.
In 2008, manufacturers of skin care-products decided to avoid them in their formulations and now EU ministers have decided that nanosilver particles (used in washing machines and in shoes to get rid of nasty smells) and multiwalled carbon nanotubes should be banned in electronic and electrical products. Members of the EU Environment Committee made this call during their vote on possible amendments to the “Restriction of Hazardous Substances Directive.”
In addition, the Committee has recommended that all electrical and electronic products (including fast-computers and solar cells) that contained “nanomaterials of any nature” should be so labeled as containing them. Hence an onus would be on manufacturers to provide safety hazard information on any nanomaterials that their products may contain. This appears quite tricky for example given the putative application where carbon nanotubes could be used as “synthetic nerves” in limb prosthetics, by acting as template around which neural tissue might grow. As introduced into the human body directly, any potential toxicity might prove rather difficult.
My awareness of the toxicity of carbon nanotubes is that the jury is out. I know of one study of them designed to search for the formation of free-radicals (toxic, short-lived molecules derived from oxygen) which seemed to indicate that the nanotubes actually soaked-up these species, leaving less of them than would be the case in their absence. That said, there are other studies that support a toxic role for carbon nanotubes. Since silver nanoparticles act in cleaning biological stains and smells by producing hydroxyl and other oxygen radicals, which are toxic in vivo, then if they were ingested the consequences could be dire.
The vote on the proposals is due in October, as reported in the July 2010 edition of Chemistry World, published by The Royal Society of Chemistry.
U.K. Joins Europe On Biogas 'Waste Into Energy' Strategy
Jul 13th
The European Union has a major drive to turn all kinds of waste into energy, particularly from biogas. There are two main incentives for this, the first being the geological feature that natural gas is in finite supply and world production of it is thought might peak within the next few decades, and secondly that burning fossil carbon contributes to the atmospheric concentration of CO2, which scientific consensus accords will cause global warming and climate change. To address either issue, finding a renewable (non-fossil) source of methane is encouraged.
The claims over how important biogas could be to help secure Britain’s energy future are certainly extravagant, and Mark Fairbairn from the National Grid thinks that it could provide for half the country’s gas by 2050 in substitution for natural gas. Given that UK gas consumption is around 103 billion cubic metresĀ of natural gas annually (i.e. around 3.6 trillion cubic feet, tcf) 50-odd billion m^3 (1.8 tcf) of biogas would need to be produced per year to meet this projection. This, roughly (assuming that 6,000 cubic feet of natural gas has an energy equivalence of one barrel of oil) amounts to an equivalent of 300 million barrels or 41 million tonnes of oil. That does sound rather a tall order – to put it mildly.
In Germany biogas is already being fed into into the national gas grid and in Sweden and Spain, vehicles including buses are run on biogas, but they still use an awful lot of oil overall and most of the small number of gas-powered vehicles are run on petroleum-gas. In Yerevan, Armenia, where I was last May, I noticed buses and lorries resplendent with rusty-looking cylinders of gas as their fuel supply, which is more cheaply obtained than liquid fuels, but I emphasise that it is petroleum gas (mainly propane and butane) that is used there and not biogas.
Also in Germany, there are aerobic digesters which are fed by maize (corn) rather than waste and so the same argument would arise over growing crops for fuel or for food as applies to biodiesel production and must ring an eventual death-knell for both biodiesel and biogas, if the latter is made from food too. It is ridiculous to compromise indigenous food-production in any nation, since all nations will find it increasingly untenable to import food on the vast scale most currently do, in the absence of cheap oil or gas.
It is true that a small amount of biogas is produced from landfill and sewage and used for energy in the U.K., but it is anticipated that “new incentives” (i.e. forms of financial encouragement; tax breaks maybe?) will mean that this kind of conversion of waste into fuel would find more extensive applications, including the use of compressed biogas for transport. It sounds great but I question the usual scale-up and engineering required to inaugurate a huge infrastructure based on biogas. In my opinion, like solar energy, the greatest opportunity for the technology is in providing energy for small communities rather than as some attempt to preserve the energy status quo, which is simply unsustainable without fossil fuels, including gas.
