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Help from elephants in cooling buildings

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Elephant ears play a crucial role in keep the giant animals cool.  Elephants don’t have significant sweat glands.  Instead, they rely on their large ears to regulate body temperature.  Their ears make up 20% of their body’s surface area.  The ears act like a natural air conditioner, making use of a network of blood vessels close to the surface that help dissipate heat when it’s hot and absorb heat when it’s cold.

Researchers at Drexel University have developed a new approach to passive heating and cooling that has the potential to make buildings more energy efficient.  The idea, published in the Journal of Building Engineering, embeds the equivalent of a vascular network within cement-based building materials.  The network, when filled with paraffin-based material, can help passively regulate the surface temperature of walls, floors, and ceilings.

Building energy demand contributes almost 40% of the production of greenhouse gas from energy use, and about half of building energy use is spent maintaining comfortable temperatures.

The new temperature regulation method puts a grid of paraffin-filled channels in the surface of building concrete.  When temperatures drop, the paraffin transitions from liquid to solid and releases heat energy.  When ambient temperatures rise, the paraffin absorbs heat energy, producing a cooler surface.  This is essentially the same way elephants as well as jack rabbits regulate their temperatures with their large ears.

The Drexel study was a proof-of-concept effort, but the results are promising enough to warrant further work.  With additional testing and scaling, it has the potential to make a significant contribution to ongoing efforts to improve the energy efficiency of buildings.

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Drexel Engineers Want to Make Buildings More Energy Efficient by Making Walls, Floors and Ceilings More Like Elephant Ears

Photo, posted September 1, 2016, courtesy of Nane Kratzke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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

Tracking emissions by satellite

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Carbon dioxide and nitrogen oxides are two of the most problematic human-generated air pollutants that negatively impact air quality, the climate, and human health.  Satellites are an important tool for monitoring emissions of these pollutants, but they have limitations.  For the most part, satellites have limited spatial resolution, meaning that they can’t reliably narrow down the source of emissions sufficiently to pin down a specific location such as a power plant. 

Until now, there have been no instruments that can detect both carbon dioxide and nitrogen oxide simultaneously with high spatial resolution.  Often just nitrogen oxide measurements are made, and carbon dioxide levels estimated based on the fact that both are emitted together with typical ratios.

A German research team from the Max Planck Institute and the Heidelberg Institute have developed a technology for the EnMAP environmental satellite to detect both gases with an unprecedented spatial resolution of 30 meters.  Data from the satellite makes it possible to track multiple sources of emission plumes over several tens of kilometers.

The EnMAP system was originally designed for remote sensing of land surfaces.  The new research demonstrates that reliable measurements of trace gases are possible even with an instrument not specifically designed for atmospheric observations.  When using it, it’s possible to determine the distribution of carbon dioxide and nitrogen oxide in emission plumes from individual power plants.  The ability to measure both gases individually means that conclusions can be drawn about the technology, efficiency, and operating mode of the systems being measured.

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German satellite measures CO2 and NO2 simultaneously from power plant emissions for the first time

Photo, posted September 19, 2020, courtesy of Sandor Somkuti via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Vertical-axis wind turbines

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Nearly all wind turbines in use today are horizonal axis wind turbines.  They are a familiar sight with their three giant rotor blades spinning about an axis high above the ground attached to a nacelle containing the gearbox and generator. 

A vertical-axis wind turbine has its rotor shaft transverse to the wind; that is, the shaft rises up from the ground and the gearbox and generator are located close to the ground.

This type of wind turbine does not need to be pointed into the wind, which eliminates the need for wind-sensing and orienting mechanisms.  It is also considerably quieter in operation than horizontal axis wind turbines.  Vertical-axis wind turbines have enjoyed minimal success to date because of a variety of problems including reliability issues and complications related to how they respond to changing wind conditions.

A next-generation vertical wind turbine is going on trial in Australia as part of a research collaboration between Flinders University in South Australia and the start-up company VAWT-X Energy.  The 6KW prototype will be installed at a field site in Australia’s Fleurieu Peninsula.

According to the developers, the new turbine design will be as efficient, or even more efficient, as existing horizontal turbines and will be able to thrive across diverse environments including being part of urban infrastructure where their relative quiet is a real advantage.   Such turbines would be more accessible for applications like off-grid power and sustainable energy solutions for small businesses and farms.  The developers claim the technology can also be scaled up for large-scale windfarms.

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Progress with new-look wind turbine

Photo courtesy of VAWT-X Energy.

Earth Wise is a production of WAMC Northeast Public Radio

Hydrogen-powered aviation

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The transportation sector is responsible for about a quarter of human-generated greenhouse gas emissions.  Most of the energy used by transport systems comes from fossil fuels.  The transition to electric vehicles – cars, trucks, and buses – is making a real difference.  However, the emissions from the aviation industry have continued to grow faster than those of other forms of transportation.  There have been increased efforts to develop hydrogen-powered aircraft, but the challenges are substantial.

Hydrogen can be used for aviation both as a directly combusted fuel, or to power electric fuel cells.  Its advantages are that its use produces no carbon dioxide, and, in fact, hydrogen produces more energy per pound than jet fuel.

A study by researchers at MIT looked at the prospects for hydrogen use in aircraft and what needs to be done to make it practical.  The biggest issue is that the extra bulk of a hydrogen fuel tank and fuel cells in a plane would have to be offset by weight reductions elsewhere, such as reducing payload (cargo or passengers).  This would mean there would need to be more flights, thereby reducing the gains made.  The researchers argued that improvements in fuel cell power and more weight efficient fuel systems could eliminate the need for additional flights.

The bigger challenge is the infrastructure for generating and distributing hydrogen.  There needs to be green hydrogen – hydrogen produced without carbon emissions – and the infrastructure for getting it to planes where it is needed has to also not produce substantial emissions.

The study suggests that the rollout of hydrogen-based aviation should start at locations that have favorable conditions for hydrogen production.

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Fueling greener aviation with hydrogen

Photo, posted December 20, 2016, courtesy of Dylan Agbagni via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A better way to extract lithium

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Lithium is the critical component in the batteries that power phones and computers, electric cars, and the systems that store energy generated by solar and wind farms.  Lithium is not particularly rare, but it is difficult and often environmentally harmful to extract from where it is found.

Traditional ore sources are increasingly difficult and expensive to mine.  The largest known deposits of lithium are in natural brines – the salty water found in geothermal environments.  These brines also contain other ions like sodium, potassium, magnesium, and calcium, and efficiently separating out the lithium is extremely challenging.

Traditional separation techniques consume large amounts of energy and produce chemical waste, particularly hazardous chlorine gas.  These techniques typically suffer from poor selectivity; that is, the process is interfered with by the other ions present in natural brines.

A team of researchers at Rice University has developed a three-chamber electrochemical reactor that improves the selectivity and efficiency of lithium extraction from brines.  The middle chamber of the reactor contains a specialized membrane that acts as a barrier to chloride ions, preventing them from getting to the electrode area where they can form chlorine gas.

The new reactor has achieved a lithium purity rate of 97.5%, which means the setup can effectively separate lithium from other ions in the brine and allow the production of high-quality lithium hydroxide, the key material for battery manufacturing. 

The Rice University reactor design has the potential to be a game changer for lithium extraction from geothermal brines.

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‘Game changer’ in lithium extraction: Rice researchers develop novel electrochemical reactor

Photo, posted October 21, 2023, courtesy of Simaron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mining extinct volcanoes

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Rare earth elements are a group of 17 elements that are used to improve the performance, efficiency, and durability of a wide range of products.  More than 200 products across a diverse set of applications make use of rare earth elements.  Although the amount of rare earth used in a particular product may not be very much of its weight, volume, or monetary value, it may often be necessary for the device even to function.  Rare earth elements react with other elements to form compounds that are essential because of their specific chemical behaviors. 

Rare earth elements are not actually rare; in fact, they are fairly common.  But they are mostly not found in their pure form and are generally difficult to refine.  China accounts for more than 90% of global production of rare earth elements and this represents a strategic problem for the rest of the world.

New research by scientists from the Australian National University has found that some extinct volcanoes, which have not erupted for thousands or even millions of years, may be rich sources of rare earth elements.  Furthermore, those elements may be easier to extract than the ones from other sources because the iron-rich magma that formed the volcanoes could be up to 100 times more efficient at concentrating rare-earths than magma found in active volcanoes today.

The clean tech industry uses rare earths for wind turbines, solar panels, and electric cars.  The demand for rare earths may grow fivefold by the end of this decade.  Relying on just one country for the world’s supply is a major concern.  There are ancient volcanoes all over the planet and they may represent a solution to a global problem.

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Extinct Volcanoes Could Be Source of Key Metals Needed for Clean Tech

Photo, posted June 6, 2020, courtesy of Dennis Jarvis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The impact of climate change on agriculture

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Agriculture is a major part of the climate problem and remains one of the hardest human activities to decarbonize.  Agriculture is responsible for approximately 30% of global greenhouse gas emissions.

On farms around the world, excess fertilizer gets broken down by microbes in the soil, releasing nitrous oxide into the atmosphere.  Nitrous oxide is a greenhouse gas that is 300 times more potent than carbon dioxide.

According to a sweeping global research review recently published in the journal Science, greenhouse gas emissions from agriculture are now 18 times higher than they were in the 1960s. 

The research, which was co-written by professors at the University of Minnesota with more than 20 experts around the world, also reveals the likelihood of an emergent feedback loop between climate and agriculture.  As the changing climate puts more pressure on the global food supply, agriculture will, out of necessity, adopt practices that may exacerbate its environmental impact. Without changes in agriculture, this feedback loop could make it impossible to achieve the Paris Climate Agreement goal of limiting global warming to 1.5 degrees Celsius above pre-industrial levels. 

The research identifies several agricultural practices that could improve efficiency and stabilize our food supply in the decades to come, including precision farming, perennial crop integration, agrivoltaics, nitrogen fixation, and novel genome editing. 

Finding ways to reduce the warming impact of agriculture while maintaining high crop yields are essential to both mitigating climate change and protecting our food supply from its impacts.

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Impact of Climate Change on Agriculture Suggests Even Greater Challenges to the Environment, Global Food Supply and Public Health

Photo, posted October 16, 2010, courtesy of Timlewisnm via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An electric reactor for industry

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The industrial sector accounts for nearly a third of greenhouse gas emissions in the US, which is more than the annual emissions from cars, trucks, and airplanes combined.  These emissions primarily come from burning fossil fuels to produce goods from raw materials as well as from the chemical reactions associated with production.  Many industrial processes require very high temperatures that are not easily achieved other than by burning fossil fuels.

Researchers at Stanford University have developed and demonstrated a new kind of thermochemical reactor that can generate the huge amounts of heat required for many industrial processes that runs on electricity rather than the burning of fossil fuels.  The researchers claim that the design is also smaller, cheaper, and more efficient than the fossil fuel technology it would replace.

Standard industrial thermochemical reactors burn fossil fuel to heat a fluid that is piped into the reactor, much like the way home radiators work, albeit at far higher temperatures.  The new reactor uses magnetic induction, similar to the way that induction cooktops work.  Heat is transferred by inducing a current into materials that heat up as the current flows.

A proof-of-concept demonstration powered a chemical reaction called the reverse water gas shift reaction and resulted in more than 85% efficiency.  The reaction in question converts carbon dioxide into a valuable gas that can be used to create sustainable fuels. 

The Stanford researchers are working to scale up their new reactor technology and expand its potential applications.  They are working on designs for reactors for capturing carbon dioxide and for manufacturing cement. 

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Electric reactor could cut industrial emissions

Photo, posted October 30, 2022, courtesy of Helmut via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water from thin air

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The Earth’s atmosphere contains enormous amounts of water.  Being able to efficiently and economically extract some of it to provide drinking water would be extremely beneficial to the billions of people across the globe who face chronic water shortages.

There are existing technologies for atmospheric water harvesting – or AWH.  But there are downsides associated with size, cost, and efficiency.   A new device developed by mechanical engineering researchers at the University of Utah has the potential to provide a new drinking water source in arid places.

The device is a compact, rapid-cycling, fuel-fired AWH device.  It relies on adsorbent materials that draw water molecules out of non-humid air and then applies heat to release those molecules into liquid form.

Hygroscopic materials are those that have an affinity for water and soak it up at every opportunity.  Such materials are used, for example, in disposable diapers.  The Utah device makes use of metal organic frameworks, which have enormous amounts of surface area on the molecular scale.

The initial work on the Utah device targeted a small compact water generation unit for soldiers in the field.  Instead of lugging around a large canteen filled with water, the small unit can produce water on demand.  The prototype was able to produce 5 liters of water per day per kilogram of adsorbent material.  Within three days in the field, the system outperforms packing water.  The heat required to precipitate the liquid water was provided by a standard-issue Army camping stove.

Non-military needs are the ultimate application for the device.  The researchers have applied for a patent for what they hope will be a potential solution to a persistent global problem.

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Producing water out of thin air

Photo, posted August 9, 2012, courtesy of Enid Martindale via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A giant solar plus storage facility

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One of the country’s largest co-located solar and battery energy storage projects is now fully operational.  The Gemini Solar+Storage project is located in Clark County, Nevada, about 30 minutes outside of Las Vegas.

The project’s 1.8 million solar panels can generate up to 690 megawatts of electricity, which is enough to supply about 10% of Nevada’s peak demand.  The facility is co-located with 380 megawatts of 4-hour battery storage, which is enough to supply Nevadans with 1,400 MWh of power after sundown.

The project makes use of a unique storage configuration that allows the storage system to be charged directly from the solar panels, resulting in increased efficiency and maximizing the capture and storage of solar energy.

The project has minimized the environmental impacts to the nearly 5,000-acre site.  Primergy, the project developer, took measures to leave vegetation in place, installed solar panels to follow the ground’s natural contours, and reduced the overall footprint by more than 20% through careful design.  The project created 1,300 union and prevailing wage jobs and contributed $483 million to Nevada’s economy.

Solar facilities are increasingly co-located with battery storage plants.  There is a huge project in Kern County California that includes 1.9 million solar panels capable of generating 875 megawatts of solar power and storing 3,287 megawatt-hours of energy.  The deserts of the southwest are prime locations for such facilities.

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The house always wins: Massive Gemini solar + storage outside of Las Vegas reaches commercial operations

Photo courtesy of Quinbrook Infrastructure Partners.

Earth Wise is a production of WAMC Northeast Public Radio

Industrial heat and solar power

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Many industrial processes require extremely high temperatures, typically more than 1,800 degrees Fahrenheit.  This heat is generally produced by burning fossil fuels – either coal or natural gas – which emits large amounts of greenhouse gases. This level of heat cannot be economically produced using renewable electricity.  As a consequence, decarbonizing these industrial processes is very difficult.

Researchers at ETH Zurich in Switzerland have recently demonstrated a new method of obtaining high-temperature heat based on solar radiation.  They have engineered a device called a thermal trap.  It consists of a quartz rod coupled to a ceramic absorber that can efficiently absorb sunlight and convert it to heat.

In laboratory-scale experiments, they exposed a foot-long quartz rod to artificial light 135 times more intensive than sunlight and were able to produce temperatures as high as 1,900 degrees.  The artificial light source was needed to mimic the effects of concentrated solar energy plants that typically make use of large numbers of mirrors to direct intense solar energy onto a small area.

There are already concentrated solar power plants that operate at temperatures as high as 1,100 degrees and use the heat to operate turbines to generate electricity.  These plants lose efficiency at higher temperatures because of radiative heat losses.  The Zurich thermal trap minimizes these losses and permits higher temperature operation.

The hope is that at a large scale, the new approach may make it possible to use solar energy to decarbonize energy-intensive industrial processes.

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Using solar energy to generate heat at high temperatures

Photo courtesy of ETH Zurich / Emiliano Casati.

Earth Wise is a production of WAMC Northeast Public Radio

Wireless car charging

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It’s increasingly common to see cars hooked up to charging cables in shopping centers, rest stops, and dedicated charging stations.  Charging electric cars is easy to do, just like charging phones and laptop computers.  These days, it is pretty common to charge phones without using any charging cable at all because of the availability of wireless charging technology.  The same thing may well happen with electric cars.

A team of researchers at Oak Ridge National Laboratory has successfully demonstrated wireless charging of electric cars with high efficiency and fairly fast charging speed.

The patented system was used to charge up a Hyundai Kona EV using electromagnetic fields, which is essentially how phone chargers work.  The technology makes use of a polyphase electromagnetic coupling coil, which is lightweight and small.  Rotating magnetic fields generated in the coil’s windings boost the power available.  The system provided 100-kW of power with 96% efficiency.  That isn’t as powerful as the fastest high-speed charging stations, but it is considerably more than any home charging solution can provide.  For many vehicles, such a charger could provide 50% battery capacity in less than 20 minutes.

Battery technology continues to improve leading to larger capacity, faster charging, longer battery life, and lower cost.  At some point, charging up an electric car will take no more time than pumping gas.

The Oak Ridge researchers consider this development to be a breakthrough achievement that could open the door to fast and efficient wireless charging for electric passenger vehicles.  One could imagine having the ability to drive up to a charging spot and charging up the battery without even getting out of the car. 

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Charging up the commute

Photo, posted July 12, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Who’s driving electric?

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Electric cars are growing in popularity around the world and are expected to represent 20% of new car sales this year.  In some places, they have a much bigger share:  38% in China and a whopping 82% in Norway.  Here in the U.S., things are more complicated.

Last year, EVs represented 8.5% of U.S. new car sales while hybrids accounted for an additional 10%.  But enthusiasm for plug-in vehicles was by no means universal or consistent across the country or across various segments of the population.

Overall, the West Coast, and especially California, dominated the electric vehicle market.  Electric vehicles accounted for more than 30% of new car sales in the San Francisco Bay Area.  In Los Angeles, the number was close to 25%.

A number of metro areas elsewhere also had strong EV sales, including Denver, Las Vegas, Washington DC, Austin, and Phoenix.  New York City had almost 10% EV registrations. 

Americans buying electric cars so far tend to be richer, younger, and more likely to live in urban areas than the average person and are often motivated by environmental concerns.  Meanwhile, about half of American adults say they are not likely to consider purchasing an EV as their next car and that figure rises to 70% for Republicans.

Lack of interest in EVs is often based on concerns about the availability of sufficient charging options or high EV prices, although those are dropping.  There is also concern about EV efficiency in colder climates, although the Norwegians clearly don’t find it to be a problem.

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Electric Vehicles

Photo, posted October 18, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

AI’s Environmental Footprint

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Artificial intelligence is everywhere these days.  Some say it is the biggest development since the discovery of fire.  There is a lot of hype regarding AI, and it will be a while before the hype is sorted out from the reality.  But one thing that is certain is that AI is resource-intensive and has a large environmental footprint.

AI use directly produces carbon emissions from its consumption of non-renewable electricity and is also responsible for the consumption of billions of gallons of fresh water.

Various forms of AI run on many types of devices, but the kind of AI we hear about the most – such as ChatGPT – requires specialized computer equipment that runs in large cloud data centers.  There are roughly 10,000 such centers worldwide and more are under construction.  Estimates are that electricity consumption from data centers will double between 2022 and 2026 to a total of 1,000 terawatts, roughly as much electricity as all of Japan uses.

These estimates include all data center activities, not just AI.  Most operators of data centers don’t reveal what percentage of their energy use comes from AI.  One exception is Google, which says machine learning accounts for about 15% of its data center energy use.

Data centers also consume a great deal of water to cool delicate electronics.  In 2022, Google’s data centers consumed about 5 billion gallons of fresh water.

AI has the potential to improve the efficiency of systems, improve climate models, and perhaps help develop new ways to help reduce humanity’s environmental footprint.  But at the moment, it represents an increasing burden on the environment that cannot just be ignored.

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As Use of A.I. Soars, So Does the Energy and Water It Requires

Photo, posted January 23, 2023, courtesy of Aileen Devlin / Jefferson Lab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How to reduce pollution from food production

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Present in animal manure and synthetic fertilizers, nitrogen is an essential nutrient for plant growth and is a critical input to enhance agricultural productivity on farms around the world.  But excessive and inefficient use of this nutrient is widespread.  In fact, up to 80% of it leaks into the environment, mostly in various polluting forms of nitrogen: ammonia and nitrogen oxides (which are harmful air pollutants), nitrous oxide (a potent greenhouse gas), and nitrate (which affects water quality).

A new report prepared for the United Nations has put forth some solutions to greatly reduce nitrogen pollution from agriculture in Europe.  A group of researchers coordinated by the U.K. Centre for Ecology & Hydrology, the European Commission, the Copenhagen Business School, and the National Institute for Public Health and the Environment of The Netherlands produced the report.

In it, the research team puts forth its recipe to reduce nitrogen pollution in Europe.  The report’s ingredients include:

  • Reducing by 50% the average European meat and dairy consumption
  • More efficient fertilizer application and manure storage
  • Reducing food production demand by reducing food waste by retailers and consumers
  • Better wastewater treatment to capture nitrogen from sewage
  • Adopting policies addressing food production and consumption to transition them towards more sustainable systems

Taking action to reduce nitrogen pollution will require a holistic approach involving farmers, policymakers, retailers, water companies, and individuals. 

Do Europeans have an appetite for change?

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Scientists provide recipe to halve pollution from food production

Photo, posted March 10, 2022, courtesy of USDA NRCS Montana via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Farming the frozen north

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Agriculture is the primary cause of land-based biodiversity loss.  As the global population grows, agricultural production needs to keep pace.  Estimates are that production needs to double by 2050.  How this can be accomplished without doing further harm to the environment and biodiversity is extremely challenging.

Climate change adds further complications to the challenge.  As the climate warms in the middle latitudes, agricultural zones may need to shift northward to regions which have evolved to have more suitable climates.  This represents a very real threat to the wilderness areas of Canada, Russia, and Scandinavia.  These places represent a significant fraction of the world’s wilderness areas outside of Antarctica.

According to researchers at the University of Exeter in the UK, if the forces driving climate change are not diminished, over the next 40 years warming temperatures are expected to make more than 1 million square miles newly suitable for growing crops.  As cropland goes barren in areas that have warmed too much, northern wilderness could be turned over to farming.  The vital integrity of these valuable areas could be irreversibly lost.

The study, published in the journal Current Biology, also says that climate change will shrink the variety of crops that can be grown on 72% of the land that is currently farmed worldwide.  Given this situation along with the rising global population, it is essential that land be used more efficiently.  We can feed a larger population from the farmland we already have, but people need to reduce meat consumption, cut food waste, and grow crops suited to their local climate.

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Warming Could Make Northern Wilderness Ripe for Farming, Study Finds

Photo, posted September 7, 2016, courtesy of Scott 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

Better Zinc Batteries | Earth Wise

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The rapid growth of wind and solar power continues to drive a global quest for new battery technologies that can be used to store the energy generated by these sources when the sun isn’t shining, and the wind isn’t blowing.

For the most part, current battery energy storage systems use lithium-ion batteries – the same sort of batteries found in cellphones and electric vehicles.  There are many other battery chemistries, but they mostly have shortcomings in performance, economy, or longevity. 

Batteries store electricity in the form of chemical energy and chemical reactions convert that energy into electrical energy. Every battery has two electrodes:  the anode, from which electrons flow into external circuits, and the cathode, which receives electrons from the external circuit.  The electrolyte is the chemical medium through which the electrons flow.

One technology that has great potential is zinc-based batteries.  Zinc itself is a metal that is safe and abundant.  Batteries based on it are energy dense. However, zinc batteries have faced the challenge of having a short cycle life.  The batteries end up plating zinc on their anodes and battery performance degrades. 

A team of researchers at Oregon State University and three other universities have recently developed a new electrolyte for zinc batteries that raises the efficiency of the zinc metal anode to nearly 100% – actually slightly better than lithium-ion batteries.

Zinc batteries have a number of potential advantages over lithium-ion.  The new hybrid electrolyte developed by the researchers is non-flammable, cost-effective, and has low environmental impact.  Lithium-ion batteries rely on the supplies of relatively rare metals that are often difficult and environmentally harmful to obtain. 

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Researchers develop electrolyte enabling high efficiency of safe, sustainable zinc batteries

Photo, posted May 13, 2017, courtesy of Jeanne Menjoulet via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Windows To Cool Buildings | Earth Wise

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About 15% of global energy consumption is for cooling buildings.  Because of this, there is an ever- growing need for technologies that can more efficiently cool buildings.   Researchers at Notre Dame University have used advanced computing technology and artificial intelligence to design a transparent window coating that is able to lower the temperature inside buildings without using any energy.

The idea is to create a coating that blocks the sun’s ultraviolet and near-infrared light, which are parts of the solar spectrum that otherwise pass through glass and help to heat an enclosed room.  Cooling needs can be reduced further if the coating can radiate heat from the surface of the window so it can pass through the atmosphere into space.  Designing a coating that does both of those things simultaneously while transmitting visible light is difficult.  Coatings should not interfere with the view out the window.

The Notre Dame researchers used advanced computer modeling to create a so-called transparent radiative cooler that meets these goals.  The coating consists of alternating layers of common materials like silicon dioxide, silicon nitride, and aluminum oxide or titanium dioxide on top of a glass base and topped with a film of polydimethylsiloxane.  The computing method was able to optimize this structure far faster and better than conventional design techniques.

The researchers say that in hot, dry cities, the coating could potentially reduce cooling energy consumption by 31% compared with conventional windows.  The same materials could be used in other applications, such as car and truck windows.  In addition, the quantum computing-enabled optimization method used for this work could be used to design other composite materials.

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Clear window coating could cool buildings without using energy

Photo, posted September 6, 2015, courtesy of Robert Otmn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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