Thursday, May 31, 2012

Rare earth materials and Renewable


As the threat of global warming looms large, Governments and Industries are looking for innovative, alternative and renewable energy sources and energy efficiency solutions. But how many alternative energy sources are available and what are their potentials? How to reduce our carbon footprint without making larger new investment? How to improve the energy efficiency of the existing systems so that we can increase energy output for the same amount of fuel input and cut the cost of energy? These are some of the fundamental questions Governments and industries are grappling with, for the past few years. We are used to generating cheap energy from coal, oil and gas at the expense of the environment for several decades. We are used to water supply free of cost or at negligible cost for several decades. Governments were able to survive year after year because they were able to supply these two fundamental requirements of the people namely, energy and water at low cost. But this situation changed swiftly when scientists raised the alarm bells on carbon emission and global warming. Still many Governments, especially industrialized countries with large energy and water usage, are still playing ‘wait and watch’ game, because they cannot afford to increase the tariffs on power and water. Any such increase will make Governments unpopular and their re-election to the office doubtful. The real alternative to fossil fuels is only solar energy, which is clean, reliable and abundant. All other forms of renewable sources such as wind, geothermal, ocean thermal energy and wave energy are only offshoot of solar energy. The prime source is still the sun and the source of energy is from the chain nuclear fusion reaction of Hydrogen atom. The radiation of this nuclear reaction in the sun has to travel an average distance of 93 million miles to reach the earth, yet it is sufficient to meet current energy requirement of entire humanity by a factor of 20,000 times. But to convert sun’s light and heat energy into Electricity and other useful forms of energy, we require some rare materials which we never used in the past. They are called ‘rare earth materials’ because their available sources and supplies are rare on planet earth. But these exotic and rare earth materials are becoming indispensable in the development of renewable energy products and applications. The future growth of clean energy technologies depend on supply of such rare earth materials. Fourteen elements and related materials were selected for a criticality assessment by US Government department of energy. Eight of these are rare earth metals, which are valued for their unique magnetic, optical and catalyst properties. The materials are used in clean energy technologies as follows. Lanthanum, cerium, praseodymium, neodymium, cobalt and lithium are used in electric vehicle batteries. Neodymium, praseodymium and dysprosium are used in magnets for electric vehicles and wind turbines. Samarium is also used in magnets. Lanthanum, cerium, europium, terbium and yttrium are used in phosphors for energy-efficient lighting. Indium, gallium and tellurium are used in solar cells. The materials were selected for study based on factors contributing to risk of supply disruption. Though usage of such material is relatively small, it is anticipated that the growth of clean technologies will require a substantial quantity of these materials. Currently China is endowed with almost 95% of such rare materials in the world. These materials are available in the form of ores and minerals under the earth. They have to be mined, processed and extracted in a pure form so that they can be used in developing clean energy products of the future. We will discuss about such products and technologies in our future articles. The anomaly is the energy required to mine, process and extract these rare earth materials require energy and such energy has to come only from the sun. It is once again Nature that comes to the rescue of human beings at such critical junctures.