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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

Can All Plant Species Survive? | Earth Wise 

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Many animal populations around the world are struggling and people are mostly to blame.  Species are declining because of all sorts of things including changes in land and sea use, pollution, invasive species, and climate change.

Like many animal species, plants are also struggling to adapt to a human-dominated world.  Plants provide the planet with food, oxygen, and energy, and are used to produce fibers, building materials, and medicines.  Even though plants are easier and cheaper to protect, they are often overlooked in conservation efforts. 

According to a paper recently published in the journal Trends in Plant Science, preventing all future land plant extinctions across the globe is possible with the right approaches.  The author of the paper, Richard Corlett of the Xishuangbanna Tropical Botanical Garden in China, writes that “if zero extinction is potentially achievable for plants, a less ambitious target would be inexcusable.” 

According to the paper, one big barrier in plant conservation is the lack of trained specialists, especially in tropical areas where there is a backlog of unidentified species.  It’s likely that many “dark extinctions,” which is when species slip away without us knowing they existed, have already occurred.

Another roadblock in preventing plant extinctions is information access, which can be solved by building an online “metaherbarium.”  This collaborative database would link digitized records from herbarium specimens with photographs, status assessments, and recovery plans.

Finally, the creation of “microreserves” – which are tiny pieces of protected land designed to get around space constraints – would further contribute to effective conservation of targeted plant species. 

Zero plant extinctions should be the goal.   

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‘Zero plant extinction’ is possible, says plant ecologist

Photo, posted May 16, 2008, courtesy of Andrew Otto via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric Cars Getting Cheaper | Earth Wise

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A sticking point for buying electric cars has always been that they are typically more expensive than equivalent gasoline-powered cars.  But increasing competition, government incentives, and falling prices for lithium and other battery materials is changing the equation.  In fact, the tipping point when electric cars are as cheap or even cheaper than internal combustion cars is likely to happen this year for many cars and, in fact, has already happened for some.

Battery production is ramping up for Tesla, General Motors, Ford, and others, creating cost savings from mass production. Companies manufacturing batteries in the United States are receiving government subsidies as part of a drive to establish a domestic supply chain and reduce dependence on China.  Before anyone cries foul, it should be noted that globally, oil companies received a trillion dollars in subsidies last year.  The Inflation Reduction Act is making it cheaper for automakers to build electric cars (provided they do it in the United States using US materials) and cheaper for consumers to buy them because of tax credits.

Multiple companies have lowered the price of their electric vehicles in recent months, including both the Tesla Model 3 and Model Y, which are the best-selling electric cars in the United States. GM’s electric Equinox crossover will start at about $30,000, which is still about $3,400 more than the gas-powered version.  But once the electric vehicle tax credit is figured in, it will actually be cheaper.

Electric cars are already cheaper to own and operate because of the much lower cost of powering with electricity instead of gas as well as the greatly reduced maintenance costs for the vehicles.  Once the purchase price of these cars is less than that of gas-powered cars, the economics becomes a no-brainer.

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Electric Vehicles Could Match Gasoline Cars on Price This Year

Photo, posted May 11, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cheaper Carbon Capture | Earth Wise

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As the years roll by without sufficient progress in reducing carbon dioxide emissions, the need for technologies that can capture CO2 from its sources or remove it from the air becomes stronger and stronger.  People have developed various ways to capture carbon dioxide, but to date, they generally suffer from some combination of being too costly or not being able to scale up to the necessary magnitude.

Scientists at the Pacific Northwest National Laboratory in Richland, Washington recently announced the creation of a new system that they claim is the least costly to date that captures carbon dioxide and turns it into a widely-used chemical: methanol.

Technologies that simply capture carbon dioxide that then needs to be stored in some secure location are difficult to implement from a cost perspective.  The PNNL researchers believe that turning CO2 into methanol can provide the financial incentive for widespread implementation.   Methanol can be used as a fuel, a solvent, or an important ingredient in plastics, paint, construction materials, and car parts.

The system is designed to be installed in fossil fuel-fired power plants as well as cement and steel plants.  Using a capture solvent developed by PNNL, the system grabs carbon dioxide molecules before they are emitted and converts them into methanol. Creating methanol from CO2 is nothing new, but capturing the carbon dioxide and converting into methanol in one continuously flowing system is new.

More work is needed to optimize and scale the process and it may be several years before it is ready for commercial deployment.

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Scientists Unveil Least Costly Carbon Capture System to Date

Photo, posted November 25, 2022, courtesy of Massachusetts Department of Environmental Conservation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Driving Electric Is Cheaper For Almost Everyone | Earth Wise

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A study by University of Michigan researchers found that about 90% of U.S. households would save money on fuel costs by owning an electric car rather than a gas-powered car.  So apart from the environmental benefits of electric cars, there are real economic benefits as well.

Both the price of gasoline and the price of electricity vary considerably across the country, so there are differences by location.  The study found that 71% of U.S. drivers would see their fuel expenses cut at least in half by driving an electric car.


Drivers in California, Washington, and New York would see the largest fuel savings as well as the biggest emissions reductions from a new electric car.  Those states have cleaner electric grids and a bigger gap between the cost of electricity and the cost of gas.

The study, published in the journal Environmental Research Letters, only looked at fuel costs and did not take into account the purchase cost of new cars.  Generally speaking, plug-in cars have higher sticker prices than gas-powered cars but multiple studies have shown that over their lifetimes, electric vehicles end up being cheaper to own than comparable gas-powered vehicles because of lower maintenance costs on top of the fuel savings.  The price gap between equivalent gas and electric cars continues to narrow in any case as the cost of batteries continues to decline.  On top of that, the recent expansion of federal tax credits on electric cars is making the vehicles cost-competitive right at the point of purchase.

Gasoline prices have come down considerably from their peak a year ago, but for almost everyone, it is still much cheaper to drive on electricity.

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Seven in 10 U.S. Drivers Could Halve Their Fuel Costs by Going Electric, Study Finds

Photo, posted April 23, 2022, courtesy of Pedrik via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Energy From Rice Straw | Earth Wise

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Rice straw is produced as a byproduct of rice production.  Globally, as much as a billion tons of rice straw is produced each year, three-quarters of it in Asia.  Straw incorporation in soil for fertilization is not practical in most places because with multiple crops per year, there is not enough time for the material to decompose and become good fertilizer.  As a result, open-field straw burning is increasingly the standard practice.

Scientists at Aston University in Birmingham in the UK are embarking on a project to convert rice straw in Indonesia into low-cost energy on a commercial scale.

Indonesia produces 100 million tons of rice waste each year, of which 60% is burned in open fields, causing air pollution. 

The Aston researchers are developing a biomass conversion process based on pyrolysis.  This involves heating the rice straw to high temperatures over 900 degrees Fahrenheit to break it down, producing vapor and solid products.  Both of these things can be used to generate electricity.

A new combustion engine designed by a company called Carnot Limited is capable of converting 70% of the thermal energy extracted from the rice straw into electricity.

Energy extracted in this way could help low and middle-income countries to create their own locally generated energy, thereby reducing emissions, creating jobs, and improving human health.   The biomass electricity is predicted to be cheaper than solar, geothermal, wind, coal, or even subsidized gas-generated power.

The Aston University project will help develop a business model that could support companies and communities to produce local, cheap energy in Indonesia and other countries with biomass capacity. 

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Aston University to help power Indonesia with affordable energy made from rice straw

Photo, posted September 11, 2006, courtesy of Kristen McQuillin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lab-Grown Meat Is Legal | Earth Wise

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We’ve heard more and more about laboratory meat.  Other names for it are cultured meat, cultivated meat, or test tube meat.  Whatever name ends up sticking, the idea is to take living cells from animals and grow them in a controlled laboratory environment to produce a meat product that doesn’t involve the slaughter of any animals.  Supporters say cultured meat is more efficient and environmentally friendly than traditional livestock.  Livestock agriculture is one of the largest emitters of greenhouse gases, uses vast amounts of land, and consumes much of the world’s fresh water.

Years ago, we reported on a company called Memphis Meats, which was one of a number of companies developing techniques for harvesting cells from animal tissues and using them to grow edible flesh in bioreactors.

Recently, that company – now called Upside Foods – has become the first company to receive FDA approval declaring their meat product to be safe for human consumption.  The USDA still needs to give its approval and it may be a little while longer before Upside’s first chicken products will end up in supermarkets.  There are more than 150 cultivated meat companies around the world backed by billions of dollars in investments.  The FDA is in ongoing discussions with multiple firms in the business.

Upside Foods, based in the San Francisco Bay area, is planning to market chicken, beef meatballs, and duck in the near future.  Other companies are working on seafood products.  Up until now, Singapore has been the only country in which lab-grown meat products are legally sold to consumers.  With this landmark FDA ruling, that is all about to change.

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US declares lab-grown meat safe to eat in ‘groundbreaking’ move

Photo, posted April 15, 2008, courtesy of Andrew Otto via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Decarbonizing Could Save Trillions | Earth Wise

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Scientists have long been calling for a transition to clean energy to prevent catastrophic impacts of climate change.  For much of that time, many people and, specifically, many of those in power, were skeptical of the need to do something about the warming climate.  But even as the facts about the changing climate became increasingly undeniable, there continued to be fears that the transition to clean energy sources would be unacceptably expensive and harmful to the economy.

A recent study published by Oxford University shows that the opposite is true:  a concerted effort to convert to green energy technologies such as solar, wind, and batteries, will save the world enormous amounts of money.

The Oxford study shows that a transition to nearly 100% clean energy by 2050 results in a lower-cost energy system that provides energy access to more people around the world.  The energy transition is expected to save the world at least $12 trillion compared to continuing our current levels of fossil fuel use.

The cost of renewable energy sources has been going down for decades and they are already cheaper than fossil fuels in many situations.  It is expected that they will become cheaper than fossil fuels across almost all applications over time.  Accelerating the transition will allow renewables to become cheaper faster.

The study made use of probabilistic models to estimate the costs of various possible future energy systems based on past data.  Even the most pessimistic models showed that scaling up green technologies is likely to drive their costs down so far that they will generate net cost savings and that the faster the transition goes, the more will be saved.  The result will be a cleaner, cheaper, more energy secure future.

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Decarbonising the energy system by 2050 could save trillions

Photo, posted July 12, 2010, courtesy of Tom Shockey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Progress On Perovskite Solar Cells | Earth Wise

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Perovskites are semiconductors with a specific crystal structure.  Their properties make them well suited for making solar cells.  They can be manufactured at room temperature, using much less energy than it takes to make the silicon-based solar cells widely used today.  As a result, perovskite solar panels would be cheaper and more sustainable to produce.  Manufacturing silicon solar cells takes a lot of energy because silicon is forged at around 3000 degrees Fahrenheit. In addition, perovskites can be made flexible and transparent, making it possible to use them in ways unavailable with silicon solar technology.

But unlike silicon, perovskites are very fragile.  The early solar cells made from perovskites in 2009 and 2012 lasted for only minutes.  Lots of potential, but little practicality.

Recently, Princeton Engineering researchers have developed the first perovskite solar cell with a commercially viable lifetime, which is a major breakthrough.  The team projects that the device can perform above industry standards for about 30 years, which is much more than the 20 years designated as a viability threshold for commercial cells.

The research team has developed an ultra-thin capping layer between two of the layers of a perovskite solar cell.  The layer is just few atoms thick but has been demonstrated to dramatically increase the durability of the device. 

There is great potential for the new solar cell technology.  It has efficiency to compete with silicon cells but can be tuned for specific applications and can be manufactured locally with low energy inputs.  If successfully commercialized, the result will be solar panels that are cheaper, more efficient, and more flexible than what are available today.

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Once seen as fleeting, a new solar tech shines on and on

Photo, posted January 8, 2020, courtesy of David Baillot/UC San Diego Jacobs School of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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The Sounds Of Coral Reefs | Earth Wise          

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Coral reefs around the world face multiple threats from climate change, pollution, and other impacts of human activity.  Reef conservation and restoration projects must be able to monitor the health of reefs and that is not such a simple matter.  Surveying reefs generally is labor-intensive and time consuming.  But in a new study, scientists at the University of Exeter in the UK have found a new way to do it.

The fish and other creatures living on coral reefs produce a vast range of sounds.  The meaning of these various sounds is for the most part unknown, but reefs nonetheless have distinctive sonic signatures.

The Exeter researchers decided to make use of machine learning technology.  They trained a computer algorithm using multiple recordings of both healthy and degraded coral reefs.  This essentially taught the computer to learn the difference between them.  A computer can pick up patterns that are undetectable to the human year.  This application of artificial intelligence can tell us faster and more accurately how a reef is doing.

The computer was then used to analyze a set of new recordings, and successfully identified reef health 92% of the time.  The team then was able to use this technique to track the progress of reef restoration efforts.

It is generally much cheaper and easier to deploy an underwater hydrophone on a reef and leave it there instead of having expert divers make repeated visits to a reef to survey its status.  Sound recorders and artificial intelligence could be used around the world to monitor the health of coral reefs and determine whether efforts to protect and restore them are working.

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AI learns coral reef “song”

Photo, posted January 11, 2015, courtesy of Falco Ermert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cheaper Electric Cars | Earth Wise

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The price of the batteries that power electric cars has fallen by about 90% since 2010.  This continuing trend will eventually make EVs less expensive than gas cars.

For many years, researchers have estimated that when battery packs reach the price of $100 per kilowatt-hour of energy storage, electric cars will cost about the same as gasoline-powered vehicles.  In 2021, the average price of lithium-ion battery packs fell to $132 per kilowatt-hour, down 6% from the previous year.  According to analysts, batteries should hit the average of $100 as soon as 2024.

It is not the case that as soon as the $100 level is reached, EVs will abruptly reach cost parity.  Across different manufacturers and vehicle types, the price shift will occur at different rates.  However, by the time batteries reach $60 a kilowatt-hour, EVs will be cheaper than equivalent gasoline models across every vehicle segment.

It is not known exactly when EVs will cost less than gasoline models, but there is little doubt that this point is coming.  We have only been talking about the purchase price of a new vehicle.  When one looks at the total cost of ownership of a vehicle, including fuel, insurance, maintenance, and depreciation, it is a different story.

Because of savings on fuel and maintenance, EVs are already in many if not most cases cheaper to own than gas-powered cars.  The Department of Energy provides an online calculator to help consumers estimate the cost differences between gasoline and electricity.

In any case, the number of electric cars on the market is increasing and the number of gas-powered cars will be shrinking.  Sooner or later, we will all drive electric.

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Inside Clean Energy: Batteries Got Cheaper in 2021. So How Close Are We to EVs That Cost Less than Gasoline Vehicles?

Photo, posted July 29, 2017, courtesy of Steve Jurvetson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing COVID-19 Spread With UV Light | Earth Wise

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New research published by the University of Colorado Boulder analyzes the effects of different wavelengths of ultraviolet light on the SARS-CoV-2 virus.   The research found that a specific wavelength of UV light is not only extremely effective at killing the virus that causes COVID-19, but also that this wavelength is safer for use in public spaces.

UV light is naturally emitted by the sun and most forms of it are harmful to living things – including microorganisms and viruses.   The most harmful UV radiation from the sun is filtered out by the atmosphere’s ozone layer.   Human-engineered UV light sources screen out harmful UV rays with a phosphorus coating on the inside of the tube lamps.  Hospitals and some other public spaces already use UV light technology to disinfect surfaces when people are not present.

The new research found that a specific wavelength of far-ultraviolet-C, at 222 nanometers, was particularly effective at killing SARS-CoV-2, but that wavelength is blocked by the very top layers of human skin and eyes.  In other words, that light has essentially no detrimental health effects for people while it is very capable of killing off viruses.

The researchers argue that this safe wavelength of Far UV-C light could serve as a key mitigation measure against the COVID-19 pandemic.  They imagine systems that could cycle on and off in indoor spaces to routinely clean the air and surfaces or perhaps create an ongoing, invisible barrier between teachers and students, customers and service workers, and other places where social distancing is not practical.  Installing these specialized UV lights would be much cheaper than upgrading entire HVAC systems in buildings.

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Specific UV light wavelength could offer low-cost, safe way to curb COVID-19 spread

Photo, posted January 18, 2008, courtesy of Phil Whitehouse via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Carbon Capture And The Infrastructure Bill | Earth Wise

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The trillion-dollar infrastructure bill contains a variety of provisions related to energy and the environment.  Among them is authorization for more than $12 billion for carbon capture technologies, including direct air capture and demonstration projects on coal, natural gas, and industrial plants and supporting carbon dioxide infrastructure.

Inclusion of this provision has largely been driven by energy companies, electrical utilities, and other industrial sectors.  The strongest proponents have been fossil fuel companies.  The reasons are fairly clear.

Support for carbon capture and storage (or CCS) technologies would yield billions of dollars for corporate polluters while allowing them to continue to burn fossil fuels.  To date, CCS technology has not progressed very far.  It is very expensive and has done little to reduce emissions. 

The strongest argument against directing significant resources into CCS for the power sector is that the plummeting costs of wind and solar energy have made renewable energy sources competitive with or cheaper than burning fossil fuels to generate electricity.  Adding expensive carbon capture equipment to a power plant only makes the economics of using fossil fuels worse.

The infrastructure bill does promote direct air capture technology, which is literally pulling carbon dioxide out of the air independent of any industrial activities generating it.  Given the world’s progress on reducing emissions, direct air capture technology may be an essential part of the global strategy to combat climate change.  If infrastructure funds largely go in that direction rather than for propping up fossil fuel companies, they may prove to be of great value.

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Fossil Fuel Companies Are Quietly Scoring Big Money for Their Preferred Climate Solution: Carbon Capture and Storage

Photo, posted March 15, 2021, courtesy of Michael Swan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Insanely Cheap Energy | Earth Wise

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The International Energy Agency, founded in 1974, keeps track of the world’s energy systems and anticipates how they are likely to change over time.  Policymakers around the world look to the agency’s annual World Energy Outlook publication for guidance.

In 2000, the agency made the prediction that by the year 2020, there would be a total of 18 gigawatts of photovoltaic solar power installed.  Within seven years, that number was already too small.

The IEA was not the only source to miss the mark on solar power.  The head of solar analysis at BloombergNEF in 2005 expected solar to eventually supply 1% of the world’s electricity.  It is already 3% and Bloomberg now predicts that it will be 23% by 2050 and expects that to be an underestimate. 

What has happened is that the world has unexpectedly gotten to the point where solar is the cheapest source of energy in most places.  Over the past decade, every time solar production capacity has doubled, its cost has dropped by 28%.

Historically, a combination of groundbreaking research in Australia and intense Chinese industrial development led to the creation of a massive new industry.  When Germany passed laws encouraging the use of solar power, suddenly there was massive global demand and a struggle to keep up with supply.

The industry had its fits and starts, and many players fell by the wayside.    But at this point, solar technology continues to get better and cheaper.  Market forces are pretty hard to beat and when solar technology can supply insanely cheap energy, it is going to be used in more and more places.

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‘Insanely cheap energy’: how solar power continues to shock the world

Photo, posted January 10, 2020, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Banning Short Plane Flights | Earth Wise

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Almost everything we do ultimately results in greenhouse gases entering the atmosphere and therefore has an impact on the climate.  But some activities have much more impact than others.  The aviation industry is responsible for about 5% of global warming.

This doesn’t seem like that large a contribution, but only a very small percentage of the world’s population flies frequently and even in richer countries, only around half the population flew in any given year (at least before the pandemic.)

Flying is generally the only practical option for most long-haul trips and unless people give up on seeing the world or conducting global business in person, they are not going to give up taking air trips.

But shorter flights are a different story.  If you are planning to take a reasonably short trip in France, a plane will soon no longer be an option.  The French government says that flights will be banned on any route where the trip could be made on a train in 2.5 hours or less.  The driving force is the reduction of CO2 emissions.  A plane trip emits an average of 77 times more CO2 per passenger than taking a train on the same route.

The Netherlands and Belgium are also considering bans on short-haul flights and Austrian Airlines recently replaced its Vienna-to-Salzburg flights with train service.

Advocates of the flight bans say that not only does taking the train significantly reduce a traveler’s carbon footprint, but it can be cheaper and actually faster than a plane when factoring in the time spent getting to airports, standing in security lines, getting on and off planes, and so on.  Europe’s extensive train system makes this approach broadly practical. Unfortunately, here in the U.S., it is not quite that easy.

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France Will Ban Short Flights That Could Be Replaced By a Train Trip

Photo, posted December 17, 2016, courtesy of Dylan Agbagni via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Plunging Cost Of Lithium-Ion Batteries | Earth Wise

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Lithium-ion batteries are the power source for phones, laptops, and electric cars.  These rechargeable batteries were first commercially introduced in 1991.  Since then, their performance has improved, and their cost has dropped tremendously.

There have been dramatic cost declines in many advanced technologies.   The price of big-screen televisions is a prime example.  Most people think of solar photovoltaic panels as the most exceptional case.  In the 1970s, solar panels cost over $100 per watt. Today, they are 20 cents a watt.

How much lithium-ion batteries have dropped in price has been somewhat unclear.  This is because much of the information about battery costs is in the form of closely held corporate data.  Most lithium-ion batteries are not sold directly to consumers but rather are built into consumer electronics and cars.  Large companies like Apple and Tesla buy batteries by the millions or manufacture them themselves, and the true costs are not publicly disclosed.

Recently, MIT researchers have carried out an extensive analysis of lithium-ion battery costs over the past three decades.  The researchers found that the cost of these batteries has dropped by 97% over that period.

It is clear that the decline in battery costs has been an enabler of the recent growth in sales of electric vehicles.  It is also clear that further declines in lithium-ion battery costs are likely to increase the batteries’ usage in stationary applications such as storing energy from intermittent green power sources like solar and wind.

The batteries have ever-improving energy density (energy stored within a given volume) and specific energy (energy stored within a given mass.)  As lithium-ion batteries continue to get better and cheaper, their role in the world continues to grow.

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Study reveals plunge in lithium-ion battery costs

Photo, posted October 26, 2020, courtesy of Ajay Suresh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Understanding How To Enhance Desalination | Earth Wise

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Desalination is the process of removing mineral components – notably salt – from saline water, generally seawater.  Over 16,000 desalination plants operate across 177 countries, generating 25 billion gallons of fresh water each year.  Currently, desalination accounts for about 1% of the world’s drinking water.

The leading process for desalination in terms of installed capacity as well as new installations is reverse osmosis that makes use of a thin-film composite membrane based on ultra-thin polyamide.

Despite the fact that these membranes are widely used for desalination, they are actually rather poorly understood.  It has not been known exactly how water moves through them.  As a result, much of the progress made on the technology over the decades has been essentially based on guesswork.

A team of researchers at the University of Texas, Austin has used advanced microscopy techniques to solve some of the mysteries of reverse osmosis membranes.  By mapping membranes at very high resolution – less than half the diameter of a DNA strand – they gained a much better understanding of what makes a membrane better at reverse osmosis.

They found that desalination membranes are inconsistent in mass distribution and density and that these inconsistencies can impair membrane performance.  It turns out that inconsistencies and dead zones in membranes play a bigger role than membrane thickness.  By making the membranes more uniform in density at the nanoscale, they were able to increase desalination efficiency 30 to 40 percent, therefore cleaning more water with less energy and at lower cost.

Producing fresh water is not just essential for public health, it is also crucial for use in agriculture and energy production.

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Nanoscale control of internal inhomogeneity enhances water transport in desalination membranes

Photo, posted February 13, 2017, courtesy of Jacob Vanderheyden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plants Paying For Biofuels | Earth Wise

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Biofuels are an important element in broader strategies to replace petroleum in transportation fuels like gasoline, diesel, and jet fuel.  The idea is that biofuels recycle carbon by getting it from growing plants rather than from fossil sources.  The biggest problem with biofuels is that they cost more than conventional petroleum fuels, so there is economic incentive to keep burning the fossil fuels.

One strategy to make biofuels cost competitive is to have the plants provide additional economic benefits beyond being a feedstock for fuel.  This in principle can be done by engineering plants to produce valuable chemical compounds, or bioproducts, as they grow.  Bioproducts include such things as flavoring agents and fragrances as well as biodegradable plastic.  These bioproducts can be extracted from the plants and then the remaining plant material can be converted to fuel. 

Researchers at Lawrence Berkeley National Laboratory recently published a study to determine what quantities of bioproducts plants need to produce to result in cost-effective biofuel production.

The study looked at a compound called limonene, which is used for flavoring and fragrance.  They calculated that if this compound was accumulated at 0.6% of the biomass dry weight, it would offer net economic benefits to biorefineries.  This corresponds to recovering 130 pounds of limonene from 10 tons of sorghum on an acre of land.

Such quantities are completely practical but, on the other hand, none of these substances are needed in huge quantities. Just six refineries could supply the world with limonene.  So, fuel crops would need to be engineered to produce a broad range of bioproducts to enable a viable cost-effective biofuel industry.

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Making Biofuels Cheaper by Putting Plants to Work

Photo, posted September 28, 2019, courtesy of Michele Dorsey Walfred via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Air Pollution With Plants | Earth Wise

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New research by Ohio State University suggests that adding plants and trees to the landscapes near factories and other pollution sources could reduce air pollution by an average of 27%.  In addition, the study indicates that, in many cases, plants may be a cheaper option for cleaning the air than more technological approaches.

The study looked at public data on air pollution and vegetation on a county-by-county basis across the lower 48 states. It then calculated what adding additional trees and plants might cost.  The calculations included the capacity of current vegetation to mitigate air pollution as well as the effects that restorative planting might have on pollution levels.

In 75% of the counties analyzed, it was cheaper to use plants to mitigate air pollution rather than add technological interventions such as smokestack scrubbers to the sources of pollution.  The results varied according to the pollution source.  For example, technology is cheaper at cleaning the air near industrial boilers than ecosystem approaches.  For the broad manufacturing industry, one approach or the other was favorable, depending on the type of factory.

Adding trees or other plants generally can lower air pollution levels in both urban and rural areas, although success rates depend on a variety of factors including how much land is available to grow new plants and current air quality.

Reducing air pollution is critical to public health.  An estimated 4 in 10 people in the U.S. live in areas with poor air quality, leading to health issues including asthma, lung cancer, and heart disease.  The study shows that nature should be part of the planning process for industry to deal with air pollution.

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Nature might be better than tech at reducing air pollution

Photo courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Roofs Going Green

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Green roofs are roofs on buildings that are partially or completely covered with vegetation and a growing medium, generally planted over a waterproofing membrane.  The modern version of these roofs began in Germany in the 1960s and spread to many other European countries over time.  With concerns about climate change and shrinking natural resources rising, green roofs are becoming increasingly popular across North America.  The Toronto-based organization Green Roofs for Healthy Cities estimates that the number in North America has increased by about 15% since 2013.

Replacing black asphalt and shingles with plants can lower the surrounding air temperature, filter dirty storm water, and reduce building energy use.  The National Research Council of Canada estimates that a green roof can reduce air conditioning use in a building by as much as 75%.  The roofs also help to reduce air pollution and greenhouse gas emissions according to the EPA.

As the benefits of green roofs become more widely known, cities around the world are passing green roof legislation.  Copenhagen passed a law in 2010 requiring all new commercial buildings to have green roofs if their roofs are not sloped too much.  Toronto was the first city in North America to pass a green roof law in 2009.  Over 640 green roofs covering more than five million square feet have since been constructed in Toronto.

Apart from the environmental benefits, green roofs are providing pleasant spaces in the urban environment that may include flower beds, trees, herb gardens, gazebos and picnic tables.  As for the economics, studies show that over the course of a roof’s lifetime, green roofs are actually considerably cheaper than conventional roofs taking into account energy savings.

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The Green Revolution Spreading Across Our Rooftops

Photo, posted July 15, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)