About Green Technology
Addressing the wide-ranging environmental impact of global population growth and industry has become critical to the survival and prosperity of human civilization. Green Technology (also known as "green tech" clean technology, or "clean tech") refers to the development of processes, practices, and applications that improve upon or replace existing technologies that allow us to meet our needs while substantially decreasing our impact on the planet. Focusing on the goals of green technology is becoming increasingly important to an diverse range of industries that includes energy, agriculture, manufacturing, and more.
American Elements is committed to meeting the material supply needs of researchers, industries, and innovators working towards a greener future.
Currently, the vast majority of the world’s energy needs are met by burning hydrocarbon-based fossil fuels. In addition to requiring non-renewable natural resources that will eventually be depleted, this method of energy production produces greenhouse gases that contribute to climate change, releases toxic gases that comprise the smog that plagues modern cities, and requires expensive and often highly-polluting methods of fuel extraction, refining, and transport. Some of these problems have grown more pressing as fossil fuels have become more scarce, requiring drilling in more remote locations, use of less-ideal raw materials such as tar sands that require more intensive processing, and increasingly complex extraction techniques such as fracking.
Today there are essentially two approaches to global warming. The first is best known from the work of former Vice President and Nobel Peace Prize Winner Al Gore, as presented in his film An Inconvenient Truth, holds that global warming should be addressed at its root cause by all of humanity working in consort through technological/industrial innovation and international governmental policy to reduce the quantity of air pollution and CO2 emissions being generated. The second approach is best expressed in the work of the environmentalist Bjorn Lomborg as presented in his writings and books, such as "Cool It" which holds that a "rational as opposed to fashionable" approach to global warming is to recognize that the least expensive method of dealing with its effects is to treat them as they occur sometimes at the very local level. This is based on the premise that when the actual effects are examined in a sober and scientific way, policymakers will discover addressing them piecemeal is significantly less costly in capital than the effort that would be necessary to reduce green house gas emissions to a point where the Earth's temperature actually began to fall again
Goal: Meeting the world’s increasing energy needs with cleaner, more sustainable energy sources and harvesting technologies.
In the long term, the solution to the many problems with fossil fuels is to transition to using solely renewable energy sources including solar, wind, geothermal, hydropower, biofuels, and waste-to-energy technologies. Maximizing the potential of these power sources will require innovation in areas such as photovoltaic materials to lower the cost and increase the efficiency of solar power, gas separation materials for efficient use of gaseous fuels, and improved heat-resistant materials for use in solar power plants. The use of cleaner power sources to power automobiles will require improved battery technology for electric vehicles and better fuel cell technology for fuel cell-powered vehicles.
In the short to medium term, however, fossil fuels will remain a significant source of energy, and therefore every effort should be made to make the use of these fuels less damaging to the environment. Efforts aimed at achieving this include the use of “clean coal” technologies to reduce pollution from power plants, as well as technologies such as catalytic converters that reduce emissions from automobiles.
Another example of a technology intended to reduce both air pollution and CO2 emissions is the use of photovoltaic cells to generate electricity (actually electrons) from photons emitted by the sun. Given the enormous amount of capital today being invested in solar energy technologies globally from Silicon Valley to the Nation of Singapore, solar energy will unquestionably play a major role in reducing green house gas emissions by supplanting hydrocarbons such as oil, coal and gas as our energy source for many applications. From its start solar energy has been essentially a field of materials science. In the 1970s the first silicon-based photovoltaic (PV) cells were produced. These basic cells were created by doping silicon to form two oppositely charged layers.
All silicon-based photovoltaic solar energy collectors, however, suffer due to their ability to absorb energy only from a relatively narrow range of the sun's light wave emission. More recently advanced materials have been developed that can either expand this band gap or create multiple band gaps in order to absorb a greater portion of the solar energy spectrum. This has lead to the development of PV cells based on Copper Indium Selenide (CuInSe2) or "CIS" Absorption Layers which can capture energy from portions of the light's spectrum not collected by silicon-based PV cells. Doping CIS with Gallium increases the band gap even further and as such most PV cells are now based on Copper Indium Gallium Selenide (CuInGaSe2) and are referred to as "CIGS".
Other promising designs include cells based on III-IV Nitride materials and research on Zinc Manganese Telluride, Cadmium Telluride (CdTe) and Gallium Selenide P-Type layers. The band gap for III-IV Nitride materials, such as Gallium Indium Nitride, covers nearly the entire energy spectrum of the sun because of multiple band gaps in the semiconductor materials. Similarly, Zinc Manganese Telluride crystals have three band gaps which can absorb greater than 50% of the solar energy spectrum. Further important research involves nanotechnology approaches using nanoparticles of the above materials.
An example of materials science playing a part in eliminating production of green house gas causing air pollutants is in the use of solid oxide fuel cells (SOFCs). Technologically, SOFCs are all materials science. There are no moving parts in the conversion of hydrogen to electricity. They are comprised of three layers: an electrically conductive cathode made of one of several crystalline perovskite materials such as Lanthanum Strontium Manganite (LSM), Lanthanum Strontium Ferrite (LSF), Lanthanum Strontium Cobaltite Ferrite (LSCF), Lanthanum Strontium Chromite (LSC), and Lanthanum Strontium Gallate Magnesite (LSGM); an ionically conductive electrolyte, such as Yttria Stabilized Zirconia or YSZ (Zirconium Oxide stabilized with Yttrium Oxide), Gadolinia doped Ceria or GDC (Cerium Oxide stabilized with Gadolinium Oxide, Yttria doped Ceria or YDC (Cerium Oxide stabilized with Yttrium Oxide), and Scandia Stabilized Zirconia or SCZ (Scandium Oxide stabilized with Zirconium Oxide; and an electrically conductive anode, which usually is Nickel Cermet compositions of nickel oxide and yttria stabilized zirconia. As hydrogen is pumped under pressure through the electrically conductive anode layer and oxygen is made available through the electrically conductive cathode layer, a circuit is completed through the ionically conductive electrolyte completing the circuit. As long as hydrogen is pumped into the system, electricity will be generated.
SOFCs are electrochemical power sources that are fueled by hydrogen and produce no air pollutants, making them an attractive choice for powering automobiles. However, because they still rely on hydrocarbons as their energy source, they do not eliminate generation of CO2 emissions. This would require the creation of a hydrogen infrastructure which is often discussed but is not being seriously proposed at this time due to both safety concerns and the cost to produce, store and transfer hydrogen.
Hydrogen can easily be generated from renewable energy sources, making it a primary focus in the area of alternative energy research. Hydrogen is the most abundant element in the universe and is produced from various sources such as fossil fuels, water and renewables. As a fuel source, hydrogen is nonpolluting and forms water as a harmless byproduct during use. The challenges associated with the use of hydrogen as a form of energy include developing safe, compact, reliable, and cost-effective hydrogen storage and delivery technologies. Currently, hydrogen can be stored in these three forms: compressed hydrogen, liquid hydrogen, and chemical storage in the form of metal hydrides.
Battery technology has grown rapidly due to the wide-spread use of rechargeable solid-state batteries in computers, vehicular applications and portable electronics. Batteries contain a number of voltaic cells; each voltaic cell consists of two half cells connected in series by a conductive electrolyte containing anions and cations. The type of chemical reaction that can be used in an electrochemical cell is known as an reduction-oxidation (redox) reaction in which one chemical species gives electrons to another. Anions, which are negatively charged ions, oxidize at the anode in the reduction-oxidation reaction, while cations, positively charged ions, are reduced at the cathode. By controlling the flow of ions between the two species through separation, battery engineers make devices in which virtually all of these electrons can be made to flow through an external circuit, thereby converting most of the chemical energy to electrical energy during the discharge of the cell.
Converting wind energy into electricity using various blade and turbine systems has been utilized since the mid-1970s when tax incentives were written in many states to encourage public utilities to purchase the power generated. Many of these earlier systems failed to deliver efficient energy and were only financially viable as tax shelters. More recently advanced materials, particularly advanced ceramics such as yttria stabilized zirconia (YSZ) and composites, have played a part in the development of lighter, less costly and more efficient wind turbines. Additionally, the decades of experience with wind as an energy source has allowed for the design of better overall wind generator "farms" placed in strategically determined locations, such as the 4,000 megawatt farm proposed by T. Boone Pickens in Texas.
The Nuclear Power Dilemma
One source of energy that is entirely free from greenhouse gas emissions is nuclear energy, power generated by the fission of enriched radioactive isotopic materials. Nuclear generators are the single greatest source of energy that in no way impacts global warming. However, all nuclear fission systems generate some form of radioactive waste which must be disposed of. Given the lengthy half-life of the waste materials, "disposal" actually means perpetual storage. The green technology goal of sustainable growth dictates that human activity not produce waste products that cannot be perpetually reused or recycled; the waste generated by nuclear power not only violates this standard but also poses risks to the health and safety of individuals and the environment. However, public policy may come to view the careful management and storage of nuclear waste as a better alternative than allowing for the continual rise in global temperatures from burning fossil fuels.
Another possible solution to the problem of global warming is geothermal energy, or power generated by heat stored in the earth from the formation of the planet, the radioactive decay of minerals, and solar energy absorbed at the surface. Geothermal energy has been used for bathing since Paleolithic times, in the form of hot springs and other natural formations, and for living space heating since ancient Roman times. The earliest industrial exploitation of geothermal energy began in 1827 with the use of geyser steam to extract boric acid from volcanic mud in Larderello, Italy. Lord Kelvin invented the heat pump in 1852, and Heinrich Zoelly had patented the idea of using it to draw heat from the ground in 1912. But it was not until the late 1940s that the geothermal heat pump was successfully implemented. The 1979 development of polybutylene pipe greatly augmented the heat pump’s economic viability.
Today geothermal energy is now better known for generating electricity. Direct geothermal heating is used for district heating, space heating, spas, desalination, industrial processes, and agricultural applications. The Earth's internal heat naturally flows to the surface by conduction at a rate of 44.2 terawatts, (TW,) and is replenished by radioactive decay of minerals at a rate of 30 TW. These power rates are more than double humanity’s current energy consumption from all primary sources, but most of it is not recoverable. In addition to heat emanating from deep within the Earth, the top ten metres of the ground accumulates solar energy (warms up) during the summer, and releases that energy (cools down) during the winter.
Geothermal power is cost effective, reliable, sustainable, and environmentally friendly, but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels. As a result, geothermal power has the potential to help mitigate global warming if widely deployed in place of fossil fuels. Methods have been developed to remove silica from high-silica reservoirs. In some plants silica is being put to use making concrete, and hydrogen sulfide is converted to sulfur and sold. At power plants in the Imperial Valley of California, a facility is being constructed to extract zinc from the geothermal water for commercial sale.
Goal: Reduce overall energy usage, contamination of our environment, and consumer-generated waste
The realization that increase in consumption after World War II was causing an equally massive generation of waste products for which there was little technology or public policy to address spawned the original environmental movement with its emphasize on reducing ground, air and water pollution. As policies and technologies were created to address pollution, it became clear that the real long term goal must be to ultimately establish a fully sustainable planet: one that could perpetually sustain itself in its present form through better management of its resources. This would require efforts on several technological fronts. First, products needed to be designed and built with an eye towards eliminating wasteful materials used and the reuse and recycling of the materials that are used once the product has exhausted its useful life. Second, reliance on difficult to replenish resources from timber to oil needed to be drastically reduced through the development of new recyclable advanced materials.
Energy conservation is essential both to minimizing the impact of our current usage of fossil fuels, and to make the complete replacement of those fuels with renewable energy sources possible. Energy needs can be reduced through the use of more efficient devices that require less power to achieve the same purpose, as when light emitting diodes or improved fluorescent bulbs replace traditional incandescents. These technologies will only continue to expand in use as material innovations allow for more applications and lower costs. Buildings can be designed to demand less energy by using more effective insulation, maximizing the use of natural lighting, and using passive solar heating and cooling. Automotive manufacturers can improve vehicle efficiency through the use of next generation materials such as metal foams that allow for lighter vehicles with better mileage without compromising the structure of the vehicle.
Solid State Lighting
By narrowly controlling the particles distribution (PSD) of quantum dot nanocrystals to within 10 nanometers, discreet colors with long term photostability can be emitted with wave lengths representing the entire visible spectra. Prior to quantum dots, light emitting semiconductors such as light emitting diodes (LEDs) could not emit white light, making them unsuitable for interior lighting.
Currently, lighting consumes 22% of all electricity produced in USA. Lighting is the single biggest user of electricity: incandescent light bulbs are only 1-4% efficient. Fluorescent lighting is significantly more efficient at 15-25%, however, solid state LED lighting can more than double that at 20-52% efficient, and LEDs are thought to have the potential for 60-80% efficiency. The U.S. Department of Energy estimates over $98 billion in energy savings could be realized by 2020 if solid state lighting can achieve an efficiency target of 200 lumens/Watt (60%), alleviate the need for up to 133 new power stations, eliminate about 258 million metric tons of carbon, and save around 273 TWh/year in energy.
Materials innovations are essential for reducing and remediating pollution. One of the most successful means of reducing air pollution has been the requirement that catalytic converters be installed in automobiles to reduce the release of nitrogen and sulfur-containing side products of fuel production. The catalysis that occurs in these devices requires expensive precious metals, and catalyst support materials that maximize effectiveness while limiting the amount of these metals required. Catalyst supports in these devices are typically high-performance ceramics that can withstand the heat of an engine. Similar ceramic materials may be used in filtration devices for removing pollutants from air streams or contaminated water.
In addition to removing polluting compounds after the environment has been contaminated, or capturing them at the site of production, it is possible to prevent the possibility of pollution from some sources by using less hazardous materials. Toxic metals such as cadmium, arsenic, and lead are found widely in electronics, while dangerous synthetic organic compounds are found in or used in making a wide variety of products. Replacing these with nontoxic alternatives prevents their release into the environment when the products containing them are eventually disposed of. The use of lead has already been substantially reduced through the use of lead-free solders in electronics, and similar improvements can be made to reduce contamination with other toxic compounds.
Reducing Consumer Waste
Currently, a large percentage of consumer products are either single-use or have short lifespans, and end their lives in a landfill where they will not biodegrade. Materials of particular concern include plastics and a variety of materials used in electronics. Plastics are entirely synthetic polymers that degrade extremely slowly in the environment, while the inorganic materials used in electronics are at best simply tied up in an unusable state in a landfill, and at worst leach out of dump sites and poison the surrounding environment.
One major way to reduce plastic and e-waste is to recycle these materials, but current recycling techniques are often energy-intensive and not always economically viable. In some cases, this problem can be addressed by designing products with reuse or recycling in mind, and improving recycling methods. Additionally, alternate materials that are renewable and biodegradable can be used in place of polluting plastics and scarce inorganic elements. Improved bioplastics can be developed to replace plastics that can not be easily recycled, while further development of organic electronics could reduce the need for traditional electronics materials.
Advanced Materials for Green Technology
Unlike the technological waves in past decades, green technologies are almost entirely focused on materials science. Making solar energy both economically and environmentally viable for widespread usage, for example, will require more energy efficient photovoltaic devices that contain fewer scarce or toxic elements, better heat resistant coatings and thermal transfer materials for solar thermal plants, and commercially viable and cost-effective energy storage technologies, all of which require advancements and innovations in materials science.
Elements on the periodic table such as copper, tin, iron and carbon are stepping aside in favor of less common metals, such as zirconium, yttrium, tellurium and the 14 elements that make of the group of metals known as the rare earths.
In addition to the use of new metallic elements is the combination of these less common metals with common metals to form new super alloys with unique properties, such as scandium-aluminum, which can combine lightness, extreme strength and high temperature and corrosion tolerance in a single material. Another example would be newly developed metal carbides that yield super hard and corrosive resistant materials with interesting properties. Similarly, the use of glass and ceramics in functional components of electronics and energy efficient systems is giving way to the use of crystal structures, semiconductors, and superconducting materials.
When Thomas Edison first did his experiments with electricity and the electronic equipment it could power, he wasn't concerned with how much copper was required to carry a circuit or the amount of power being used. As electronics became smaller and more complicated, the company he built, General Electric, became very concerned with reducing the scale and volume of metal used. Thinner conductive and semi-conductive layers and wires were necessary. Until the 1970s, this was accomplished using electroplating of metallic solutions, such as metal chlorides combined with etching technologies. Now, thin film coatings do not require electroplating and can be achieved using sputtering targets and high purity foils.
The fabrication of functional layers of materials at the nanoscale can now be accomplished by converting the material into a plasma-like chemical vapor which deposits the material on a substrate. Modern hand-held electronics rely on thin film deposition to achieve their small size.
Nanotechnology & Nanomaterials
Nanotechnology is playing an increasing role in solving the world energy crisis. Platinum nanoparticles are ideal candidates as a novel technology for low-platinum automotive catalysts. Lanthanum Nanoparticles, Cerium nanoparticles, Strontium Carbonate Nanoparticles, Manganese Nanoparticles, Manganese Oxide Nanopowder, Nickel Oxide Nanopowder and several other nanoparticles are finding application in the development of small cost-effective Solid Oxide Fuel Cells (SOFC). And Platinum Nanoparticles are being used to develop small Proton Exchange Membrane Fuel Cells (PEM). Lithium Nanoparticles, Lithium Titanate Nanoparticles and tantalum nanoparticles will be found in next generation lithium ion batteries. Ultra high puritySilicon Nanoparticles are being used in new forms of solar cells. Thin film deposition of silicon quantum dots on the polycrystalline silicon substrate of a photovoltaic cell increases voltage output as much as 60% by fluorescing the incoming light prior to capture.
Silicon nanoparticles have been shown to dramatically expand the storage capacity of lithium ion batteries without degrading the silicon during the expansion/contraction cycle that occurs as power is charged and discharged. Silicon has long been known to have an excellent affinity for storage of positively charged lithium cations making them ideal candidates for next generation lithium ion batteries. Unfortunately, the quick degradation of silicon storage units has made them commercially unfeasible for most applications. Silicon nanowires however, cycle without significant degradation and present the potential for use in batteries with greatly expanded storage times.
Metallic & Ceramic Foams
Metallic foams are becoming increasingly important in the treatment of environmental pollutants. Metallic and ceramic foams are cellular structures consisting of a solid metal or ceramic material containing a large volume fraction of gas-filled pores. The pores can be sealed, closed-cell foam, or they can form an interconnected network, open-cell foam. The defining characteristic of these foams is a very high porosity, typically 75-95% of the volume consisting of void spaces. Metallic and ceramic foams are often used in green technology applications because the high surface area facilitates the adsorption of environmental pollutants and other chemicals. They can also be used for thermal and acoustic insulation, and as a substrate for other catalysts requiring large internal surface area.
American Elements is a supplier of materials to numerous industries operating within the sphere of green technologies.
For the fuel cell industry, we produce catalyst metals such as platinum, cathode materials such as lanthanum strontium manganite, nickel cermets for use as anodes, and electrolyte materials such as yttria stabilized zirconia.
For the solar energy industry, we manufacture semiconductor materials in a variety of forms, including quantum dots. These same materials are used in conjunction with materials such as phosphors to produce more efficient technologies in the lighting industry.