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Recycling solar panels

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The use of solar energy has been growing by leaps and bounds in recent years. It is the fastest growing source of energy in the U.S.   Solar panels have a useful life of about 25 to 30 years and there are growing numbers that have been around that long.  They contain valuable materials, including silver, copper, and aluminum, as well as some hazardous materials, so just committing them to landfills is a bad idea from many perspectives.

Recycling solar panels is a relatively new but increasingly important business.  At the present time, roughly 90% of panels that have lost their efficiency due to age or that are defective end up in landfills because that is much cheaper than recycling them.  The best option is to reuse them where their reduced efficiency is acceptable.  This includes in developing nations or in other places that are able to make use of the lower power in exchange for lower installation cost.

Estimates are that the area covered by solar panels in the U.S. that are due to retire by 2030 would cover about 3,000 football fields.   The amount of potential waste contained in all of those panels is quite substantial.

There are new companies dedicated to solar panel recycling such as one called SolarCycle that are trying to change this situation.  It is much more expensive to have SolarCycle take away solar panels than to send them to landfills, but it is difficult to find landfills that accept panels and many clients want to minimize the environmental impact of their old panels.

Only 10% of retired solar panels are currently recycled. That that is likely to change as economics and regulations continue to evolve.

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As Millions of Solar Panels Age Out, Recyclers Hope to Cash In

Photo, posted November 23, 2024, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Soda can hydrogen

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Hydrogen is an ideal climate-friendly fuel because it doesn’t release carbon dioxide when it is used.  But most hydrogen is produced in ways that result in significant carbon emissions. Thus, the search for green hydrogen goes on. 

Last year, engineers at MIT developed a new process for making hydrogen that significantly reduces the carbon footprint of its production.  The recipe uses seawater and recycled soda cans. 

Pure aluminum reacts with water, breaking up the water molecules to produce aluminum oxide and pure hydrogen.  But when aluminum is exposed to oxygen, it forms a shield-like layer that prevents the reaction.

The MIT researchers found that the shield can be removed by treating aluminum with a small amount of gallium-indium alloy.  Mixing the pure aluminum with seawater not only produces hydrogen, but the salt in the seawater precipitates out the gallium-indium, making it available for reuse.

The research team carried out a “cradle-to-grave” life cycle assessment of the process, taking into account every step in using the hydrogen-production process at an industrial scale.  They found that using recycled aluminum – chopped-up soda cans – is environmentally and economically superior to using “primary” aluminum, mined from the earth. The cans would be shredded into pellet and treated with the gallium-indium alloy.  The pellets would be processed near a source of seawater where they would be combined to generate hydrogen on demand.

According to their analysis, the hydrogen produced would be at least competitive economically and environmentally with other potential methods of producing green hydrogen.

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Study shows making hydrogen with soda cans and seawater is scalable and sustainable

Photo, posted July 29, 2020, courtesy of Bruce Dupree via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Iceland power

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Iceland burns very little fossil fuel to power its economy and heat its homes.  About 85% of its energy comes from geothermal power and hydropower.  Its unique geology provides it with the highest percentage of renewable energy in the world.  The fossil fuel that Iceland does burn is primarily used to power cars and trucks as well as boats in its fishing fleet.  And Iceland is rapidly embracing the use of electric vehicles.

Iceland can make far more electricity than its 373,000 people can use.  The majority of its electricity is essentially exported as bars of aluminum.  Iceland is one of the world’s largest refiners of aluminum.  The aluminum ore comes from other countries but gets shipped to Iceland where electricity is cheap.  Refining aluminum is so energy-intensive that some say that aluminum is basically just pure electricity in solid metal form.

Electricity-rich Iceland is finding other ways to make use of its resources.  There is a proposed project called Icelink, which is an electricity interconnector between Iceland and Great Britain.  The high-voltage direct current link would run between 620 and 750 miles and would be the longest sub-sea power interconnector in the world.  It is controversial in Iceland and it may or may not happen.

Another technology that is establishing an early foothold in Iceland is carbon capture.  An Icelandic company called Carbix is doing leading work on taking captured carbon dioxide and sequestering it underground.  Capturing and storing carbon dioxide is energy-intensive and the promise of cheap, clean geothermal power makes Iceland an attractive place to do it.

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Iceland Is Living in our Future

Photo, posted July 2, 2012, courtesy of  Emily Qualey / PopTech via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Red mud and steel

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Most of us have never heard of red mud.  Otherwise known as bauxite residue, it is an industrial waste product generated by the most common process by which aluminum is made and the world produces 200 million tons of red mud each year.  The stuff is a significant environmental hazard being extremely alkaline and corrosive. Most of it ends up in large landfills and the costs associated with disposing of red mud are substantial.

Red mud is red because it contains large amounts of iron oxide, often as much as 60% of it.  Scientists at the Max-Planck Institute in Germany have developed a method for producing steel from red mud that is much less carbon intensive than traditional steel production and that is economically viable.

The scientists melt the red mud in an electric furnace powered in part by green hydrogen.  Running the furnace this way, even when using electricity from only partially renewable sources, results in far fewer greenhouse gas emissions as well as economic benefits.  In the furnace, liquid iron separates from the other liquid oxides and can be extracted easily.  The resultant iron is so pure that it can processed directly into steel.  The remaining metal oxides are no longer corrosive, and they solidify into a glass-like material that can have practical uses in construction.

There are 4 billion tons of red mud that have accumulated worldwide to date.  According to the researchers, their process could produce over 700 million tons of green steel from it, potentially saving 1.6 billion tons of carbon dioxide emissions. 

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Green steel from toxic red mud

Photo, posted September 7, 2021, courtesy of Healthy Gulf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Recycling Solar Panels | Earth Wise

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Solar panels generally have a useful life of around 20 to 25 years.  The great majority of deployed panels have been installed fairly recently, so they have a long way to go.  But the growth in solar technology dates back to the 1990s, so there are growing number of panels that have already or are shortly coming to their end-of-life.

Today, roughly 90% of solar panels that have lost their efficiency due to age, or that are defective, end up in landfills because recycling them is too expensive.  Nevertheless, solar panels contain valuable materials, including silver, copper, and crystalline silicon, as well as lower-value aluminum and glass. 

The rapid growth of solar technology means that in the coming years, large numbers of retired solar panels will enter the waste stream.  The area covered by solar panels that are due to be retired by 2030 in the U.S. alone would cover about 3,000 football fields.  Clearly, more cost-effective recycling methods are sorely needed.

Engineers at the University of New South Wales in Sydney Australia have developed a new, more effective way of recycling solar panels that can recover silver at high efficiency.  The panel frames and glass are removed leaving just the solar cells themselves.  The cells are then crushed and sieved in a vibration container that effectively separates 99% of the materials contained in them.

Silver is the most valuable material contained in solar cells.  The Australian researchers estimate that between 5 and 10 thousand tons of silver could potentially be recycled from retired solar panels by the year 2050.  But even the other materials contained in solar panels are well worth recovering if it can be done cost-effectively.

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New environmentally friendly solar panel recycling process helps recover valuable silver

Photo, posted November 22, 2008, courtesy of Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Aluminum In Batteries | Earth Wise

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Batteries are playing a bigger and bigger role in our lives.  Apart from their use in ubiquitous smartphones, laptops, and other devices, millions of electric vehicles are hitting the roads, and utilities are installing giant banks of batteries to store energy generated by wind and solar farms.

The necessary characteristics of batteries are high energy density and stability.  The latter is needed so that batteries can be safely and reliably recharged thousands of times.  For decades, lithium-ion batteries have been the go-to for all these modern battery applications.  And they have gradually gotten better and cheaper all the time.  But the improvements are getting smaller, and the price reductions have limits.

For these reasons, researchers are always looking for batteries with higher energy density – so that, for example, electric cars can drive farther on a charge – and that can be made more cheaply, are not flammable, and are very stable.

Since the 1970s, researchers have investigated the use of aluminum for the anode of batteries because its properties would allow more energy to be stored.  However, when used in lithium-ion batteries, aluminum developed fractures and failed after a few cycles.

Researchers at Georgia Tech University have developed a type of aluminum foil with small amounts of other materials that create specific microstructures.  Used in battery anodes, this material does not degrade and appears to be a path to a better battery.  When incorporated into a solid-state battery that does not contain the flammable liquid found in standard lithium-ion batteries, the result is a battery that checks most of the boxes in the search for a better battery.

Much more work is needed to assess the potential for the aluminum-based battery, but it looks very promising.

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Aluminum Materials Show Promising Performance for Safer, Cheaper, More Powerful Batteries

Photo, posted August 27, 2019, courtesy of Marco Verch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Aluminum And Deodorants | Earth Wise

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Aluminum is the third most common element in the earth’s crust.  That element and its compounds are contained in numerous foods and products intended for consumers.  Aluminum can occur naturally in certain foods and it can be a part of food additives.  Apart from that, it is also possible for aluminum to transfer to food from packaging and tableware.   We also can take in aluminum from cosmetic products like whitening toothpaste, lipsticks, particles in sunscreens, and in the form of aluminum chlorohydrate in antiperspirants.

The concern about aluminum intake is related to its effects on the nervous system, on the mental and motor development of children, and upon possible negative effects on the kidneys and bones.  When aluminum is ingested via food, its toxicity is low and for healthy people, the kidneys do a good job of excreting it.  However, people with chronic kidney disease may not be able to get rid of aluminum as readily and it can accumulate in the body.

Six years ago, a study looked at the amount of aluminum absorbed through the skin from the use of antiperspirants, but the data at that time was considered to be unreliable and a need for further research was identified.

Recently, the results of two new studies have been published by a German research institute that quantifies the absorption of aluminum salts through the skin.  The results were that significantly less aluminum is absorbed through the skin than previously calculated and that a significant absorption of aluminum from antiperspirants is unlikely.

The total burden of aluminum from all sources can be high among some population groups, but it appears that use of aluminum-containing antiperspirants is not an important contribution to that burden.

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Aluminium in antiperspirants: Low contribution to the total intake of aluminium in humans

Photo courtesy of NutritionFacts.org.

Earth Wise is a production of WAMC Northeast Public Radio.

Concrete Production And Diminishing Coal Burning | Earth Wise

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Coal burning is still one of the primary means of generating electricity in the United States, but its use is diminishing and doing so fairly rapidly.  The coal burning process produces residual, incombustible materials.  One of them is fly ash, which is composed of fine, glassy, rounded particles rich in silicon, aluminum, calcium, and iron oxides.  Fly ash is captured from coal plant flue gas by precipitators and bag filters. It turns out that two-thirds of this fly ash is not dumped into landfills or impoundments, but rather is put to use.

Because of its chemical and physical characteristics, fly ash can substitute for a portion of portland cement in concrete.  Using this byproduct material in making cement actually reduces its cost. Beyond cost, the addition of fly ash as a so-called supplementary cementitious material or SCM improves concrete’s long-term strength and reduces porosity and permeability.  It reduces the risk of thermal cracking and provides good long-term mechanical properties.

The amount of fly ash used in concrete products increased by 5% between 2011 and 2017 while the amount produced dropped by 36%.  Concrete production continues to increase steadily while fly ash production is steadily dropping.

Therefore, the concrete industry is looking for alternative sources of SCM.  The most obvious is the approximately 1/3 of fly ash that hasn’t been used to make concrete.  Much of that is landfilled or ponded onsite at power plants.  So, opportunities exist for excavating or dredging and recovering these materials.

As coal burning goes away, concrete manufacturing needs to make some changes.

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What Does the Changing Face of Electricity Production Mean for Concrete?

Photo, posted February 16, 2017, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Fresh Produce | Earth Wise

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Fresh fruits and vegetables can sometimes become contaminated by microorganisms during their long journey from fields to restaurants and grocery stores.  Contaminated produce can spoil other produce, which increases the number of fruits and vegetables in the supply chain that can cause illnesses. 

In order to prevent this cross-contamination between produce, researchers from Texas A&M University have designed a coating that can be applied to food-contact surfaces, like buckets, rollers, and conveyor belts.  The newly-created dual-function coating is both water-repellent and germicidal.  In other words, it can both repel and kill.  Without water, the researchers say bacteria can’t stick or multiply on surfaces, drastically reducing contamination.

To make this dual-function coating, the researchers chemically-attached a thin layer of silica to an aluminum sheet.  They then added a mixture of silica and lysozyme, a naturally-occurring germicidal protein found in egg whites and tears.  Together, the silica-aluminum and the silica-lysozyme formed microscopic bumps and crevices.  According to the research team, this rough texture, albeit microscopic, is the key to the coating’s superhydrophobic properties.  

The researchers tested the coating’s effectiveness at curbing the growth of two strains of disease-causing bacteria:  Salmonella and Listeria.  Upon review, the number of bacteria found on the dual-coating surfaces was 99.99% less than what was found on the uncoated surfaces. 

Despite the success in preventing bacterial spread, the research team said more research needs to be done to see how well the coating works for mitigating viral cross-contamination.  Since the coating would need to be reapplied after a certain amount of use, the researchers also plan to develop more permanent, dual-function coatings. 

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New dual-action coating keeps bacteria from cross-contaminating fresh produce

Photo, posted April 14, 2012, courtesy of U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Other Ways To Cut Vehicle Emissions

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It is pretty clear that the way to drastically reduce vehicle greenhouse gas emissions is to switch as many vehicles as possible to electric power.  As a result, more and more localities are putting in place policies that encourage electrification.

While there is no doubt that electrification is the long-term solution to vehicle emissions, a recent study by MIT and the Ford Motor Company found that, in the short term, there are some places in the US where electric cars are not the best way to reduce emissions.

The study looked at a variety of factors that affect the relative performance of vehicles.  These include the role of low temperatures in reducing battery performance, regional differences in the average number of miles driven annually, and significant differences in the way electricity is generated in different parts of the US.

The results showed that electric vehicles definitely provide the greatest impact in reducing greenhouse gas emissions for most of the country – and particularly on both coasts and in the south – but that there are some places in the upper Midwest where the greatest reduction would be achieved by the use of lightweight gasoline-powered vehicles.

In places like parts of Wisconsin and Michigan, it is mostly rural, there are cold winters, and electricity is predominantly generated by coal-powered plants.  In these places, if gas-powered lightweight cars were to be used, the overall benefit would be greater than that of electric cars.  Unfortunately, there are no high-volume lightweight gasoline-powered mid-sized cars on the market in the US.  Ironically, the only cars of that class using lightweight aluminum construction are Teslas.

While electric cars are truly the long-term solution, the study does demonstrate the benefits of reducing the weight of vehicles.

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What’s the best way to cut vehicle greenhouse-gas emissions?

Photo, posted February 9, 2018, courtesy of Dave Field via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Using The Sun To Remove Ice

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Ice buildup can cause all sorts of problems ranging from performance issues to catastrophic failures.  For example, ice buildup can negatively impact things like airplanes, power lines, wind turbines, and the like.  Preventing this ice buildup typically requires energy-intensive heating systems or environmentally-harmful chemical sprays.

[Read more…] about Using The Sun To Remove Ice

A New Low-Cost Battery

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Batteries have never been more important.  Not only do we all depend on cell phones, tablets and laptop computers that run on batteries, but two enormous industries are in major transitions that rely upon battery technology: personal transportation and the utility industry.   The electricity grid is increasingly turning to solar and wind power for generation and both will require effective energy storage if they are to truly become the predominant sources of electricity.

[Read more…] about A New Low-Cost Battery

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