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A common plant could be a valuable food source

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A new study by researchers at Penn State University has found that a common water plant in the eastern U.S. could be a valuable green fertilizer, a feed for poultry and livestock, and even a life-saving food for people in the event of a catastrophe or disaster.

The plant is the Carolina azolla.  It is sometimes called mosquito fern, fairy moss, or water fern. It is a water plant that grows very rapidly; it can double its biomass in two days.   There are many varieties of azolla, but the Carolina strain is more digestible and nutritious for people than any of the others.

Azolla species have been used across the world for centuries as a livestock feed and as a fertilizer.  They have not been good for human consumption because of high polyphenolic content, which can be 10 times more than that of common food plants.  Polyphenols are abundant compounds in many plants and, in low concentrations, are beneficial antioxidants.  But in high concentrations they act as antinutritional agents.

It turns out that the Carolina azolla – described as having a crisp texture and neutral taste – has a polyphenolic content comparable to many fruits, nuts, and vegetables.  Furthermore, cooking significantly decreases the polyphenolic content in foods.

Carolina azolla has significant nutritional value including high mineral yields and calories,  and moderate protein content.  Whether it is used as a quick-fix in a disaster situation or as part of a long-term resilience plan, the study concludes that Carolina azolla holds excellent potential for use as a fast-growing, short-season crop that requires minimal effort to grow and process and could be used to increase food security in a hungry world.

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Common plant could help reduce food insecurity, researchers find

Photo, posted October 8, 2020, courtesy of Dana L. Brown via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record renewable energy in Scotland

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The Scottish government recently announced that in 2022, renewable technologies in that country produced the equivalent of 113% of Scotland’s electricity consumption.

Fossil fuels still supplied electricity in Scotland, helping to fill in gaps in renewable power, but the government figures showed that the growing amount of Scottish renewable generation can easily generate more power than the country uses.  Scotland has seen significant growth in wind power as well as a small drop in overall electricity consumption.

Scotland, with a population of only 5.5 million, aims to produce enough renewable power to both meet its own demand and export clean electricity to other countries.  The U.K. is the obvious potential customer, but it will need to upgrade its national power grid and develop enough capacity to store up surplus wind and solar power.

The U.K. itself is drawing less power from natural gas and coal than it has at any point in the last 66 years.  Fossil fuels supplied only 33% of British electricity in 2023 while renewables supplied 43%. 

Fossil power use in Britain peaked in 2008.  Since then, power from natural gas has fallen nearly in half while coal power has dropped by 97%.  The U.K. has aggressive decarbonization goals in place, but the current Conservative government under Prime Minister Sunak has recently set about weakening British climate policy.

Meanwhile, the Scottish government is talking about becoming a global renewables powerhouse and is making investments aimed at achieving it.

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Record renewable energy output

Photo, posted July 21, 2010, courtesy of Martin Abegglen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Protecting wine grapes from wildfire smoke

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In recent years, wildfires have become a major threat to the wine industry because of the effects of smoke on wine grapes.  Smoke taint from the California fires of September 2020 significantly impacted the quality of wine grapes.  In total, smoke taint cost the wine industry in Western states more than $3 billion in losses from the hundreds of thousands of tons of wine grapes that could not be harvested because of the off flavors imparted by the smoke.  The California wine industry alone is a $43 billion a year business and the state’s frequent wildfires are a major threat to it.

Researchers at Oregon State University have developed techniques for eliminating the effects of three volatile chemical compounds that contribute to smoke taint in grapes.  The compounds are guaicol, syringol, and meta-cresol.

The researchers developed cellulose nanofiber-based coatings that can be applied to grapes in the vineyard.  The coatings can block guaicol and syringol and capture meta-cresol.

Blocking is ideal because the coating doesn’t absorb the wildfire smoke compounds.  Therefore, it doesn’t have to be washed off.  Capturing means the coating absorbs the compounds and would need to be washed off.  Ideally, a coating that doesn’t need to be washed off would save time, money, and water.

Two years of studies at Oregon State found that the coatings do not impact the growth and quality of wine grapes.  In an era when wildfires are increasingly common and extensive, growers need something they can spray on their vines to protect their grapes.  If the Oregon State technology can be commercialized, it would be a game-changer for the Western U.S. wine industry.

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Spray coating for grapes shows promise in battle between wildfire smoke and wine

Photo, posted October 3, 2006, courtesy of Naotake Murayama via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

One in five cars will be electric this year

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There has been lots of turbulence in the electric car industry of late.  Part of it is aggressive publicity campaigns spreading misinformation and part of it is the natural fits and starts associated with major change.  But apart from the ups and downs of individual companies and countries, analysts are projecting another record year for the sales of electric vehicles and are expecting that plug-in cars will account for 20% of all car sales globally.  Much of the growth will be driven by China, where 38% of new car sales will be electric cars.

Global sales of plug-in cars are expected to grow by 21% this year, according to Bloomberg New Energy Finance.  Total projected sales are 16.7 million cars, including 1.9 million in the U.S., 3.4 million in Europe, and 9.7 million in China.  Because of the rapid adoption of electric cars in China, that country is expected to reach peak gasoline demand this year.  In other words, the use of gasoline in China will be diminishing from now on.

The auto industry is in flux.  The traditional big automakers are currently slowing down EV manufacturing as they work to come up to speed with the technology and market demand.  Meanwhile, EV-only carmakers such as Tesla in the U.S. and BYD in China are ratcheting up production. BYD is focusing on emerging economies with its lower-priced offerings.

In the U.S., EV adoption has been slowed somewhat by high interest rates and the slow rollout of EVs by the Big Three automakers.  But many new vehicles by a growing list of automakers will provide customers with more and more choices of EVs to suit diverse tastes and needs.

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This Year One in Five Cars Sold Globally Will Be an EV

Photo, posted November 18, 2023, courtesy of RL via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Elephants and protected areas

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Standing up to 13 feet tall and weighing up to 7 tons, African savanna elephants are the largest species of elephant and the biggest terrestrial animal on Earth.  According to the World Wildlife Fund, African savanna elephants can be found in 23 countries and live in a variety of habitats, including savannas, forests, and deserts.  The largest populations are in Southern and Eastern African countries.

According to assessments from the International Union for Conservation of Nature, the population of African savanna elephants has decreased by at least 60% over the last 50 years.  Poaching and habitat loss are the two main drivers of the population decline.  In 2021, the status of the African savanna elephant was changed from vulnerable to endangered on the IUCN’s Red List of Threatened Species. 

However, according to a new study recently published in the journal Science Advances, conservation measures have successfully stopped African savanna elephant population declines across southern Africa.  The international team of researchers found that the pattern varies regionally, with some elephant populations soaring while others are still facing large declines.

Overall, the study found that there are the same number of elephants now as there were 25 years ago. According to researchers, the key to long-term elephant population growth and sustainability isn’t where a protected area is, but rather how connected it is to other protected or neutral areas around it. 

This isn’t a new concept; in fact, many parks have been connected to one another.  But this study helps prove that the method is effective for elephant conservation.  

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Protected Areas for Elephants Work Best if They Are Connected

African elephant species now Endangered and Critically Endangered – IUCN Red List

African savanna elephant

Photo, posted October 20, 2018, courtesy of Ray via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Airplanes, corn, and groundwater

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The aviation industry wants to slash its greenhouse gas emissions.  One proposed strategy is to replace ordinary jet fuel with ethanol.  Ethanol in this country mostly comes from corn.  The airlines are enthusiastic about the idea; corn farmers are enthusiastic about the idea.  Ethanol suppliers are obviously enthusiastic about it.  But is it a good idea?

Today, nearly 40% of America’s corn crop is turned into ethanol.  Twenty years ago, the figure was around 10%.  The massive growth was the result of mandates for ethanol augmentation of gasoline for environmental reasons.

But the environmental benefits of corn ethanol have always been controversial at best when all the energy factors are considered. But apart from that, a very serious issue is that corn is a water-intensive crop, and it can take hundreds of gallons of water to produce a single gallon of ethanol.  As the climate warms and corn crops expand, groundwater in many corn-growing areas is being increasingly depleted and groundwater provides half our drinking water and meets far more than just the needs of corn farmers.

Corn farmers and ethanol producers see the rapid growth of electric vehicles as a threat to their lucrative business of supplying the auto fuel industry.  The ambitious goals of the airline industry to reduce its emissions would likely require nearly doubling ethanol production.

The situation is a powerful example of the tradeoffs that can arise as the world tries to make the transition away from fossil fuel.  Even green solutions can have their own environmental cost and sometimes that cost may be too steep.

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Airlines Race Toward a Future of Powering Their Jets With Corn

Photo, posted September 2, 2007, courtesy of Rosana Prada via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cleaning the grid can create messes

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The electric grid is increasingly embracing renewable energy sources like solar and wind power as well as the energy storage systems that support them.  These generation sources differ from traditional sources in that they produce direct current electricity rather than alternating current electricity.  Our power grid runs on alternating current.  Traditional generators produce alternating current that synchronizes with the grid.  Wind and solar power connect to the grid using electronic power converters called inverters that produce the required alternating current. 

All of this technical detail is something we don’t pay much attention to, except that the current state of inverter technology can lead to some problems that don’t exist with a fully synchronous power system. 

The electric grid frequently experiences disruptive events like trees falling on powerlines, squirrels shorting out substation equipment, and so on.  These things normally don’t cause widespread trouble, although there have been notable exceptions such as the massive Northeast blackout of 2003 triggered by an overloaded transmission line drooping onto foliage.

The issue with inverters is that they can shut down in the presence of certain disturbances to the grid.  This has happened on a number of occasions and has exposed vulnerabilities that need to be addressed by the industry.  Inverter-based resources currently constitute only a relatively small fraction of the grid, but that fraction is growing steadily and can have an increasingly widespread impact.  The grid was built predominantly for synchronous generation, and it must be adapted and improved to assure the reliability that is required and expected.  It is an issue that can’t be ignored.

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Renewables are cleaning the grid. They’re also messing it up

Photo, posted July 5, 2017, courtesy of Sue Thompson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Seabirds rescuing coral reefs

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A new study by researchers at Lancaster University in the UK has found that the presence of seabirds on islands adjacent to tropical coral reefs can more than double the coral growth rates on those reefs.

The study found that when coral reefs grow faster, they can bounce back more quickly from bleaching events that occur when the seas become too warm.  The focus of the study was a type of coral called Acropora, which provides complex structures supporting fish populations and reef growth. 

The researchers found that Acropora around islands populated by seabirds recovered from bleaching events about 10 months faster than reefs located away from seabird colonies.  Speeding up coral recovery times could prove the difference between continuing to bounce back from bleaching events and dying off.

The seabirds are helping the coral reefs with their droppings.  The birds feed on fish in the open ocean far from islands and then return to the islands to roost.  They deposit nitrogen- and phosphorus-rich nutrients in the form of guano, some of which is washed off of the islands by rain and into the surrounding seas.  The nutrients fertilize corals and other marine species.

To determine whether the faster growth rates were really due to the bird-supplied nutrients, the researchers studied rat-infested islands that had no bird populations.  The study confirmed that it was the presence of seabirds that provided enhanced nutrients for the coral reefs.  In fact, a primary outcome of the study was to add further weight to the growing body of evidence of the ecological damage across ecosystems on land and sea from invasive rats on tropical islands.

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Feathered friends can become unlikely helpers for tropical coral reefs facing climate change threat

Photo, posted September 15, 2019, courtesy of Rickard Zerpe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

New York’s first offshore wind farm

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New York has set a target of installing 9 GW of offshore wind capacity by 2035.  The first offshore wind farm in the state – South Fork Wind – was approved by the Long Island Power Authority in 2017.  Construction began in 2022.

South Fork Wind Farm is a 132 MW project sited 35 miles offshore from Montauk, New York.  Early this year, the subsea power export cable was installed by Nexans, a cable and optical fiber company.  In June, the project reached its “steel in the water” milestone with the installation of the farm’s first monopile foundation.

In November, the first of South Fork Wind’s 12 Siemens Gamesa wind turbine generators was hoisted into place by the offshore construction team.  The turbines are being installed by a specialized vessel called the Aeolus.  Turbine installation involves using a crane to place the steel turbine tower onto the foundation.  The nacelle and rotor are then installed on top of the tower.  Finally, the blades are bolted one by one to the rotor.

All 12 turbines for the project are expected to be installed by the end of this year or by early 2024.

There have been setbacks for the U.S. offshore wind industry in recent times.  Two projects in New Jersey have been scrapped because of supply chain issues.   Rhode Island Energy pulled out of a project citing higher interest rates, increased expenses, and problems with tax credits.

But despite these setbacks, the industry continues to make headway.  Vineyard Wind in Massachusetts is on the precipice of delivering its first power to the grid and the pipeline of additional projects continues to grow.

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First turbine installed at South Fork Wind, New York’s first offshore wind farm

Photo, posted August 7, 2013, courtesy of SSE / Department of Energy and Climate Change via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record low Antarctic sea ice

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Antarctica’s winter came to a close in September and during that month, the continent reaches its maximum amount of sea ice that grows during the darkest and coldest months.  This year, that maximum occurred on September 10th and turned out to be the lowest on record.

The sea ice around Antarctica reached a maximum extent of 6.5 million square miles according to NASA researchers.  That was nearly 400,000 square miles below the previous record low set in 1986. 

There are several possible causes for the meager growth of Antarctic sea ice this year.  It may be a combination of several factors including El Niño, wind patterns, and warming ocean temperatures.  Recent research indicates that ocean heat is most likely playing an important role in slowing ice growth in the cold season and enhancing ice melting in the warm season.

The record-low ice extent so far this year is a continuation of a downward trend in Antarctic sea ice that has gone on since the ice reached a record high in 2014.  Prior to that year, the ice surrounding the southern continent was actually increasing slightly by about 1% every decade.

Meanwhile, Arctic sea ice reached its minimum extent in September and it was the sixth-lowest level in the satellite record.  Scientists track the seasonal and annual fluctuations of polar sea ice because they shape polar ecosystems and play a significant role in global climate.  Sea ice melting at both poles reinforces global warming because bright sea ice reflects most of the Sun’s energy back to space while open ocean water absorbs 90% of it.

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Antarctic Sea Ice Sees Record Low Growth  

Photo, posted June 30, 2023, courtesy of Pedro Szekely 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

The Captive Lion Problem | Earth Wise

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In the 1990s, there was rapid growth in South Africa of the private wildlife industry.  Large numbers of cattle, sheep, and goat ranchers replaced their domestic livestock with wild animals that wealthy hunters would pay lots of money to shoot.  Lions were among the most prized targets for these people.  Over time, hundreds of ranchers became involved in the business of breeding large numbers of the big cats in cages or small enclosures.  Wealthy clients paid $25,000 to $40,000 to shoot a captive-bred lion – cheaper than the cost of a true wild lion hunt and much easier too.  The animals were not afraid of humans and were easy to find.

By 2015, about 200 ranches held at least 8,000 captive-bred lions.  Over 600 were trophy-hunted that year, generating about $16 million in trophy fees, mostly from Americans.

Journalists and conservationists exposed poor conditions on many lion farms and many other abuses.  Over time, the South African government cracked down on the export of lion bones and other body parts for taxidermy, traditional Chinese medicine, and other uses.  The days of captive lion breeding seemed numbered but shutting down the lucrative industry is not easy.

Wild lions in South Africa are not endangered.  In fact, existing sanctuaries and preserves have as many lions as they can sustain.  What to do with thousands of captive lions is a real problem.  Some have suggested mass euthanasia, but that appalling idea has garnered very little support.  The future of these animals still hangs in the balance and so far, there are really no truly desirable solutions in the offing.

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If South Africa Ends Lion Breeding, What to Do With Captive Cats?

Photo, posted August 21, 2011, courtesy of Leszek Leszczynski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Missing Antarctic Sea Ice | Earth Wise

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It is summer here in the United States, but it is winter in Antarctica.  Antarctic sea ice is water that forms and melts entirely in the ocean and it has a pattern of growth and reduction that has been monitored by satellites for the past 44 years.  The area of sea ice that surrounds the continent of Antarctica is known as the sea ice ‘extent’ and it had been quite stable for much of those years.

In 2016, the sea ice extent began to decline.  Since then, there have been several record summer lows with both the summers of 2021/22 and 2022/23 setting new minimum records.

This August, the deviation from all previous records intensified.  This winter’s sea ice extent is over 900,000 square miles below the long-term average, an area about the size of Greenland or, for example, Texas and Alaska combined.

Climate models have long predicted that Antarctic sea ice would reduce as a result of global warming but the current change to sea-ice extent is so dramatic that it is difficult to explain.  Sea ice extent is affected by multiple factors including the El Niño Southern Oscillation, the strength of the southern hemisphere jet stream, and regional low-pressure systems.  The warming climate is certainly the overall force that is changing Antarctic sea ice extent over time.

Antarctic sea ice extent is important because it covers a vast area of the dark Southern Sea with a bright white surface that reflects the sun’s energy back into space, helping to reduce temperatures at the pole and protecting glaciers and polar ice sheets. 

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The mystery of the missing Antarctic sea ice

Photo, posted November 7, 2016, courtesy of Rob Oo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biosurfactants And Oil Spills | Earth Wise

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About 400 million gallons of oil leaks into the ocean every year.  This is a major source of environmental pollution.  Oil contains many hazardous compounds that are toxic or mutagenic for marine organisms. 

When oil spill incidents occur, large quantities of chemical dispersants, sometimes as much as millions of gallons, are applied to dissolve oil slicks, prevent oil from reaching coastlines, and enhance the dispersion of the oil in the water.  The hope for doing this is that microbial oil degradation will be enhanced as a result.  Certain microorganisms present in the water can feed on crude oil components and break them down into harmless substances.

A study at the University of Stuttgart in Germany in 2015 showed that chemical dispersants in fact can slow down microbial oil degradation and therefore inhibit water purification.  The oil components need to be broken down sufficiently for them to be bioavailable to microorganisms.  The study found that dispersants were not accomplishing this.

A new study by the same group along with researchers from the University of Tubingen in Germany and the University of Georgia has found that using biosurfactants rather than chemical dispersants stimulates different microbial oil degraders with respect to their growth and activity and can enhance our ability to deal with oil spills.   Treating the water with the biosurfactant rhamnolipid rather than any of the generally-used dispersants provided much higher rates of microbial breakdown of oil components.

The hope is that this work can lead to the development of effective and environmentally friendly approaches to combatting oil spills.

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Biosurfactants might offer an environmentally friendly solution for tackling oil spills

Photo, posted June 11, 2010, courtesy of Deepwater Horizon Response via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Floating Solar And Hydropower | Earth Wise

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Installing solar panels on the surface of reservoirs is an up-and-coming trend.  The arrays of solar panels produce renewable energy while at the same time shielding significant expanses of water from the sun’s heat, thereby reducing evaporation.  The panels also help to inhibit the growth of algae.

Two recent floating solar installations are demonstrating the synergy between solar power and hydroelectric power.

The Lazer floating solar plant in France comprises over 50,000 solar panels and is capable of producing 30 MW of power.  The reservoir serves a 16.5 MW hydropower plant.  During the summer, the water from Lazer Reservoir is used primarily for crop irrigation and the solar plant supplements power generation as the reservoir water level experiences variations.  This is the first facility of its kind to be installed in France.  The company that built it – the EDF Group – had already built four floating solar power plants in Israel and the US. 

In Colombia, the Aquasol solar project is installed at the 340 MW Urrá hydropower plant.  Its 2,800 solar panels produce enough power to offset the amount of energy it takes to operate the dam.  The floating solar system is designed to withstand water-level fluctuations of up to 120 feet.

Floating solar systems can help keep power flowing when low water levels or other adverse conditions reduce hydroelectric output.  About 60% of the world’s renewable energy comes from hydropower.  Given this fact, there are countless opportunities to deploy floating solar that maximizes zero-emission energy generation as well as diversifying clean energy sources.

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Floating solar and hydropower: A match made in renewable energy heaven

Photo, posted October 25, 2010, courtesy of Martin Abegglen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Below-Average Dead Zone In The Gulf of Mexico | Earth Wise

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The Gulf of Mexico dead zone, or hypoxic area, is an area of low oxygen content that can kill fish and other marine life.  It occurs every summer and is mostly a result of excess nutrient pollution from human activities in cities and farms throughout the Mississippi River watershed.  The nutrients carried by the river into the gulf stimulate an overgrowth of algae, which eventually die and decompose, which depletes oxygen in the water as the algae sink to the bottom.

The resultant low oxygen levels near the bottom of the gulf cannot support most marine life.  Fish and shrimp often leave the area seeking better places to be.  Animals that can’t swim away – like mussels and crabs – can be stressed by the low oxygen level or even killed.

The National Oceanic and Atmospheric Administration produces a dead zone forecast each year based on a suite of models developed by NOAA and partners at multiple universities. 

The latest forecast, completed in May, found that the discharge of nutrients in the rivers was about one-third below the long-term average between 1980 and 2022.  Nitrate loads were down 42% and phosphorous levels down 5%.

Based on these measurements, the scientists forecast a summer dead zone that will cover an estimated 4,155 square miles, which is 22% lower than the 36-year average of 5,364 square miles.  Ongoing efforts by the Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force to reduce nutrient levels seem to be paying off.

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NOAA forecasts below-average summer ‘dead zone’ in Gulf of Mexico

Photo, posted September 6, 2013, courtesy of NOAA Photo Library via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Big Year For Rooftop Solar | Earth Wise

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The global capacity of rooftop solar power grew by 49% in 2022.  Overall, the installed amount of rooftop solar grew from 79 gigawatts to 118 gigawatts last year and it is projected to reach 159 gigawatts by the end of this year.  By comparison, a typical nuclear power plant can produce 1 gigawatt; a gas-powered power plant is typically half a gigawatt.

Rooftop solar constitutes a relatively small fraction of the total global installed solar capacity, which is dominated by utility-scale solar arrays.  Total installed solar capacity rose from 950 gigawatts to 1,177 gigawatts last year and is projected to reach 1,518 gigawatts this year.  That is enough power to meet more than half the electricity demand of the European Union.

The rapid growth of solar power can only continue if there is more energy storage put in place to manage the peaks and troughs in solar output.  Countries will also need to upgrade their power grids to be able to transport excess solar power from where it is generated to where it is needed.   Bottlenecks in the grids of most of the leading solar-producing nations are already interfering with further solar development.

The overall potential for rooftop solar is based on the number of rooftops that would be suitable for solar power, which depends on the size, shading, orientation, and location of the roofs.  According to the National Renewable Energy Laboratory, rooftops in the United States have the potential for more than 1,000 gigawatts of solar capacity. Currently, only about 4% of US homes have rooftop solar. 

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Rooftop Solar Grew Nearly 50 Percent Globally Last Year

Photo, posted November 16, 2022, courtesy of Oliver Knight via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenhouse Gases Continue To Rise | Earth Wise

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Despite all the focus on reducing emissions of greenhouse gases, there continues to be little progress toward actually accomplishing reductions.  A combination of growing populations, increasing industrialization in the developing world, and just plain reluctance on the part of many sectors of society to act, have all contributed to the continuing buildup of climate-altering gases in the atmosphere.

Levels of carbon dioxide, methane, and nitrous oxide – the three greenhouse gases produced by human activity that are the major contributors to climate change – all continued historically high rates of growth in 2022.

CO2 levels rose by 2.13 parts per million last year, roughly the same rate observed during the past decade.  The current level of 417 ppm is 50% higher than pre-industrial levels.  Increases of more than 2 ppm have occurred for 11 consecutive years.  Prior to 2013, there had never even been 3 years in row with increases of that size.

Methane levels increased by 14 parts per billion, the fourth largest increase over the past 40 years.  Methane levels in the atmosphere are now two-and-a-half times greater than their pre-industrial level. 

The third most significant greenhouse gas – nitrous oxide – also saw a large increase, reaching 24% above pre-industrial levels.

Carbon dioxide emissions are by far the most important contributor to climate change and the continuing widespread burning of fossil fuels is the primary source.  There are widespread intentions to reduce carbon dioxide emissions, but those intentions have not yet resulted in sufficient actions.

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Greenhouse gases continued to increase rapidly in 2022

Photo, posted May 16, 2014, courtesy of 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

Community Solar On The Rise | Earth Wise

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Community solar is a way for people who can’t put solar on their own roofs to still take advantage of its benefits.  Whether they can’t afford to install their own panels, have too much shade on their roof, or don’t even own a home, community solar is another way to participate in green energy.

Community solar – also called “shared solar” or “solar gardens” – is a kind of development in which consumers can subscribe to a large solar installation in their area and receive credits on their monthly utility bills for their share of the solar electricity produced.

The large majority of community solar installations are in six states:  Colorado, Illinois, Massachusetts, Minnesota, New Jersey, and New York.  After substantial growth in community solar in 2022, New York now is the national leader, thanks to initiatives by the state government and the nonprofit sector.  Some programs focus on giving low-income households access to solar.  As of last fall, New York had over 728 community solar projects online.

One should understand that electrons are indistinguishable.  The power generated by a community solar installation is not piped directly to subscribers’ homes.  It just goes into the grid.  Subscribers get credit for their share of the power, but that is essentially a matter of bookkeeping, not physics.

The federal government now has $7 billion that can be used for community solar as part of the Greenhouse Gas Reduction Fund within the Inflation Reduction Act enacted last August.  The EPA plans to award up to 60 grants to assist projects deploying residential and community solar.  Research firm Wood Mackenzie forecasts the community solar market will double by 2027.

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Community Solar Is About to Get a Surge in Federal Funding. So What Is Community Solar?

Photo, posted November 18, 2008, courtesy of the Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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