Shortage of Resources for Renewable Energy and Food Production
Rhodes, Christopher J., Science Progress
UK government report calls for "strategic metals" plan
Not only are supplies of oil and natural gas under imminent threat of failing to meet demand for them, but so is that of a whole range of precious metals, along with indium, gallium and germanium and other vital elements such as phosphorus and helium, as is discussed throughout this commentary. A report (1) from the Science and Technology Committee, advised by the Royal Society of Chemistry, warns that if the UK does not secure supplies of strategic metals, its economic growth will be severely jeopardized. Of particular concern are indium, used in touch screens and liquid crystal displays, and rare earth elements (REEs) particularly neodymium and dysprosium, used to fabricate highly efficient magnets for electric cars and wind turbines. Platinum group metals are an issue too, used in catalytic converters and fuel cells. As is true of oil and gas, and indeed the world population, such resources are not evenly distributed around the globe, for example 80% of available new platinum is extracted from just two mines in South Africa; 92% of the niobium used in the world (for superconducting magnets and highly heat-resisting superalloys e.g. in jet-engines and rocket subassemblies) is exported from Brazil, and 97% of REEs are presently supplied from China. In developing a low-carbon transport infrastructure, it is proposed that biofuels should be used principally for aviation where there is no practical alternative to liquid fuels. Thus, it is ventured, electric cars will become increasingly important in providing personalised transport while avoiding the use of petroleum or natural-gas based fuels. The knock-on effect is that new sources of lithium must be found along with the means to mine and process the metal, plus the inauguration of recycling technology to recover it. One can immediately take issue with the practicalities of both arms of this scheme, however. Roughly 20% of all fuel in the UK is used for aircraft, or around 13 million tonnes. At a yield of 952 L/ha and a density of 0.88g/[cm.sup.3], to produce this much biodiesel would take 15.5 million hectares of arable land, of which the UK has only 6.5 million hectares. Thus if we were to stop growing food crops entirely and just rapeseed, we could still only fuel 42% of our aviation fleet. It is obvious that just a few percent at best of our current number of planes can be kept in the air by means of biofuels. Clearly, the days of cheap air-travel are numbered and this may be one reason why the coalition government has scrapped plans to build the controversial and vexed third runway at Heathrow Airport. Given the 30 million cars on British roads are currently fuelled by oil, the case for a widescale implementation of electric-cars might appear compelling. However, the lead-in time to make a dent in that number of vehicles and the 60 million tonnes of crude oil used to fuel them would be decades at best, even if the necessary supplies of REEs, lithium and overall manufacturing capacity for them could be achieved. The most practical use for electricity is to power mass transportation, e.g. tramways and railway networks rather than individual vehicles.
Endangered elements: threat to green energy
Underpinning the above political agenda, a list (2) of "endangered elements" has been published in a new report, including the REEs, in particular neodymium, production of which, it is reckoned (3), will have to increase five-fold to build enough magnets for the number of wind-turbines deemed necessary for a fully renewable future. Nonetheless, my rough calculations indicate that this would still take 50-100 years to implement, depending on exactly what proportion of the renewable electricity budget would be met from windpower, and if the manufacturing capacity and other resources of materials and energy needed for this Herculean task will prevail.
Neodymium is a rare earth metal used extensively to produce permanent magnets found in everything from computer hard disks and cell phones to wind turbines and cars. …