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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

Wealth And Greenhouse Gas Emissions | Earth Wise

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A new study led by researchers from the University of Massachusetts Amherst has found that the wealthiest 10% of Americans are responsible for a staggering 40% of the country’s greenhouse gas emissions. The study, which was recently published in the journal PLOS Climate, is the first to link income, especially income derived from financial investments, to the emissions used in generating that income.

The research team suggests that policymakers adopt taxation strategies focused on shareholders and the carbon intensity of investment incomes in order to meet the global goal of limiting temperature rise to 1.5 degrees Celsius.

Historically, environmental policies have focused on regulating consumption, but the researchers argue that this approach misses something important:  carbon pollution generates income, but when that income is reinvested into stocks, rather than spent on necessities, it isn’t subject to a consumption-based carbon tax.  Rather than focus on how emissions enable consumption, they argue that the focus should be on how emissions create income. 

After analyzing 30 years of data, the researchers found that not only are the top 10% of earners in the United States responsible for 40% of the nation’s total greenhouse gas emissions, but that the top 1% alone account for 15-17% of the emissions. Emissions tended to peak in the 45-54 age group before declining.

The researchers highlight the need for an income and shareholder-based taxation strategy to incentivize climate action among high-income earners and industries, which could expedite decarbonization efforts and create tax revenue to support other climate initiatives.

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America’s Wealthiest 10% Responsible for 40% of U.S. Greenhouse Gas Emissions

Photo, posted June 29, 2015, courtesy of Pictures of Money (via Flickr).

Earth Wise is a production of WAMC Northeast Public Radio

Lampshades And Indoor Air Pollution | Earth Wise

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We mostly think of air pollution as an outdoor problem.  Common sources of air pollution include emissions from vehicles, byproducts of manufacturing and power generation, and smoke from wildfires.  What we don’t often spend a lot of time thinking about is indoor air quality. 

Indoor air pollution refers to harmful pollutants within buildings and structures, which can lead to a myriad of health issues.  Sources of indoor air pollution include smoke from tobacco products, as well as volatile organic compounds (VOCs), including acetaldehyde and formaldehyde, emitted from things such as paints, cleaning products, plastics, and cooking. 

A team of scientists from South Korea’s Yonsei University has developed a special coating that when applied to lampshades can convert pollutants into harmless compounds.  Composed of titanium dioxide and a small amount of platinum, this thermocatalyst can be applied to the inside surface of a lampshade and is triggered to break down VOCs when warmed by the lamp’s existing incandescent or halogen bulb.

In lab tests, the coating was applied to the inside of an aluminum lampshade, warmed by a halogen bulb, and then placed into a sealed chamber containing air and acetaldehyde gas.  The researchers found that the material quickly converted the gas into acetic acid, then into formic acid, and finally into carbon dioxide and water. The scientists are now looking for ways to extend the pollutant-destroying-lampshade concept to LED lightbulbs. 

The findings offer a promising and eco-friendly solution to improve indoor air quality and reduce the health risks associated with prolonged exposure to VOCs. 

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Clever coating turns lampshades into indoor air purifiers

Photo, posted March 21, 2009, courtesy of Levent Ali via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Grid-Scale Gravity Energy Storage | Earth Wise

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As wind and solar energy play a growing part in our energy system, the need for grid-scale energy storage is growing as well.  An historic form of energy storage and still the largest in installed capacity is pumped hydro storage, which makes use of the potential energy contained in having water sitting at a higher elevation where it can be released downward to operate turbine generators.  This is an effective system but is limited to places where geography cooperates.

For the past five years, a company called Energy Vault has been developing a system that uses the same principle to generate electricity but instead of pumping water to a higher elevation, it uses mechanical devices to lift heavy objects such as concrete blocks to an appropriate height.  Lowering the blocks back to the ground drives generators.

To date, Energy Vault has only built demonstration systems with a fraction of the storage capacity needed for grid-scale operation. Their EV1 Tower in Switzerland was successfully grid interconnected in 2020 and demonstrated round-trip efficiency (the fraction of the energy stored that was produced by the generators) above 75%.  Their improved EVx system is expected to do better than 80%.

This year the company, along with partners Atlas Renewable and China TIanying, is now in the first phases of commissioning a grid-scale system located outside of Shanghai, China.  The 25-MW system is built adjacent to a wind farm and a national grid interconnection site

This is the first grid-scale gravity energy storage system and is expected to be fully online in the fourth quarter of this year.  A second, similar system is now under contract to be built elsewhere in China.

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First grid-scale gravity energy storage system undergoes commencement in China

Photo courtesy of Energy Vault.

Earth Wise is a production of WAMC Northeast Public Radio

More Offshore Wind Proposed For New Jersey | Earth Wise

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There have been three offshore wind projects previously approved by utility regulators in New Jersey.  New Jersey is vying to become an East Coast leader in the fast-growing offshore wind industry and now developers have proposed four new projects off the New Jersey Shore.

Two of the projects would be located far out to sea where they would not be visible at all from the shore.  One of them, called Community Offshore Wind, would be built 37 miles offshore from Long Beach Island.  It aims to generate enough electricity to power 500,000 homes.

A second project, called Leading Light Wind, would be located 40 miles off Long Beach Island and would consist of up to 100 turbines that would generate enough electricity to power 1 million homes.

The two companies that are building the already-approved Atlantic Shores Wind Farm have submitted a bid for a new project located 10 to 20 miles offshore.  In addition, a fourth application to the New Jersey Board of Public Utilities has also been submitted, but there is yet no public information about it.

Existing offshore projects have drawn intense opposition from homeowners in part because they are close enough to the Atlantic City and Ocean City shorelines to be seen by beachgoers, albeit as tiny objects on the horizon.  The new proposed projects located far offshore would not have this problem.

The new projects can take advantage of existing federal tax credits, but the bidders say they will not seek the tax breaks from New Jersey that the earlier project received as they have also been the subject of legal challenges by opponents of offshore wind.

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4 new offshore wind power projects proposed for New Jersey Shore; 2 would be far out to sea

Photo, posted March 25, 2016, courtesy of TEIA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Aluminum In Batteries | Earth Wise

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

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

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

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

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

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

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

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

Earth Wise is a production of WAMC Northeast Public Radio

Electric Steel Furnaces | Earth Wise

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Steel was first made thousands of years ago.  The discovery that heating up iron ore in a hot enough charcoal fire could purify the iron into a strong and valuable material was the start of the Iron Age.  In many ways, things have changed very little since then.

Global iron and steel production accounts for 7% of society’s carbon emissions. Making steel generally involves burning coal in a blast furnace to produce the very high temperatures required to turn iron into steel.  The coal is used both as a feedstock and as a fuel.  Steel is made from iron and a substance called coke, which is basically coal that has been carbonized at high temperatures.  Coal itself is burned to provide the high temperatures needed.

A new analysis from the Global Energy Monitor think tank shows that the global steel industry is slowly embracing electric-arc furnaces to produce the necessary heat, which is a cleaner alternative.  The analysis found that 43% of forthcoming steelmaking capacity will rely on electric-arc furnaces, up from 33% last year.

According to the study, the shift to cleaner steel is not happening fast enough.  To meet the emissions reductions goals of the Paris Climate Agreement, electric-arc furnaces must account for 53% of global steelmaking capacity by 2050.  Based on the current plans, those furnaces would only account for 32% of total capacity by that year.

In order to meet these goals, the steel industry will need to retire or cancel about 381 million tons of coal-based manufacturing capacity and add 670 million tons of electric-arc furnace capacity. 

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Steel Industry Pivoting to Electric Furnaces, Analysis Shows

Photo, posted March 3, 2012, courtesy of Jeronimo Nisa via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar Panels On Canals | Earth Wise

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There has been growing interest in installing solar panels on top of reservoirs to make use of the available space to make electricity and reduce evaporation.  There has been far less interest in installing solar on canals and aqueducts.  But that is changing and a new project in California is part of that change.

A study by the University of California, Merced estimates that 63 billion gallons of water would be saved by covering California’s 4,000 miles of canals with solar panels.  All that installed solar would generate a significant amount of electricity.

The idea is going to be tested in the Turlock Irrigation District in Central California with Project Nexus, which is the installation of solar panels over 1.8 miles of canals that are between 20 and 110 feet wide.  The panels will sit between 5 and 15 feet off the ground.  UC Merced researchers will study impacts ranging from evaporation to water quality and use the results to make recommendations with respect to wider use of the technology.

California isn’t the first place to put solar on a canal.  India pioneered it on one of the largest irrigation projects in the world.  The Sardar Sarovar dam and canal project brings water to hundreds of thousands of villages in the dry, arid region of India’s Gujarat State.

Meanwhile, the Gila River Indian Community in Arizona received funding from the Bipartisan Infrastructure Law to install solar panels on their canals in an effort to save water and reduce stress on the struggling Colorado River.

The world of water infrastructure does not embrace change easily but covering canals with solar panels is an idea whose time may have come.

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Solar panels on water canals seem like a no-brainer. So why aren’t they widespread?

Photo, posted December 11, 2005, courtesy of Dave Parker 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

Cleaner And Greener Steel | Earth Wise

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Producing construction materials like concrete and steel is a major contributor to greenhouse gas emissions.  Between 7 and 8% of emissions are due to steelmaking alone, which has been done pretty much the same way for more than a century.

Iron ore is smelted with high-carbon fuel and is turned into so-called pig iron in a blast furnace, which creates the key raw material for the steel industry.  The process uses huge amounts of energy (still often generated by burning fossil fuels) and releases carbon dioxide as a byproduct. 

The Department of Energy is sponsoring 40 projects at universities, national laboratories and companies in 21 states aimed at reducing industrial carbon pollution.  Ten of those projects are focused on decarbonizing iron and steel. These initiatives are part of the overall effort to move the nation towards a net-zero emissions economy by 2050.

A team headed by Case Western Reserve University that includes Lawrence Livermore National Laboratory, the University of Arizona, and steel company Cleveland-Cliffs Inc. has developed a promising new zero-carbon, electrochemical process for producing steel.

The process is a novel molten salt electrolysis method that is low-cost, capable of achieving high rates, and uses environmentally benign chemicals.  The process does not use carbon at all.  Using molten salts, electrochemistry can be performed at moderately high temperatures rather than the temperatures of nearly 3000 degrees Fahrenheit used for conventional steelmaking.  The goal is to enable steel production that is both economically viable at an industrial scale and that is environmentally sustainable.

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Case Western Reserve leading research to develop zero-carbon, electrochemical process to produce iron metal as part of U.S. Department of Energy effort

Photo, posted January 11, 2017, courtesy of Kevin Casey Fleming via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar Power And Water | Earth Wise

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Solar power is a prime example of clean energy, but it does not come without complications and potential problems.  One problem that has arisen in the Californian desert is the effect on scarce water supplies.  Solar farms don’t use up water when they are operating but they consume it when they are being built.

One of the densest areas of solar development in North America is in a corridor along Interstate 10 near Palm Springs, California.  Multiple utility-scale solar projects are underway near the small town of Desert Center.  The projects are being built on public land overseen by the Department of Interior’s Bureau of Land Management.  The location is ideal for solar power projects:  endless sunshine, nearby transmission lines to distribute power, and a major highway for easy transportation of construction materials.

The problem is that during construction of the solar farms, the law requires developers to reduce the amount of dust being generated that can otherwise spread health problems like Valley Fever.  Preventing dust from flying requires water and lots of it.

The water comes from groundwater and building the solar farms is drying up local wells and emptying the aquifer that is part of the Chuckwalla Valley Groundwater Basin.  For the people who live in Desert Center and adjacent areas, this is a serious problem. It is also a problem for the desert ecosystem that supports palo verde and ironwood trees as well as endangered desert tortoises.

This isn’t an easy problem to solve. Seven approved new utility-scale solar projects in the area will provide enough electricity to power 2 million homes. But having enough water to build those projects won’t be easy.

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Solar Is Booming in the California Desert, if Water Issues Don’t Get in the Way

Photo, posted October 16, 2017, courtesy of UC Davis College of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wind And Solar Pass Coal | Earth Wise

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For the first five months of this year, wind and solar generated more electricity than coal in the United States.  This is a first.  Total renewable energy generation exceeded coal-fired power in both 2020 and 2022, but that counted hydroelectric power as one of the renewable sources.

This year, wind and solar alone generated a total of 252 terawatt-hours of energy through May compared with coal’s output of 249 terawatt-hours.  Hydropower generated an additional 117 terawatt-hours during that period.

While solar and wind power have been expanding at a rapid rate, the biggest change this year has been a precipitous drop in coal-fired generation due to a combination of low natural gas prices, a mild winter, and a series of coal plant retirements.

Coal generated almost half of the country’s electricity as recently as 2008.  Since then, coal has steadily declined as older coal plants shut down and were replaced by natural gas plants and renewable energy sources.  The coal industry had a bit of a reprieve last year when natural gas prices spiked in response to the disruptions in gas supplies in Europe due to the war in Ukraine.  The benchmark for natural gas prices – known as Henry Hub – was $8.81 in August 2022.  In May of this year, it was $2.15.  Given this trend, the demand for coal has steadily declined. 

The US has retired another 7% of the coal fleet – 14 gigawatts of capacity – since the start of 2022.  Meanwhile, power companies have added 22.5 GW of wind and solar capacity in just the past 12 months.

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In a First, Wind and Solar Generated More Power Than Coal in U.S.

Photo, posted September 20, 2016, courtesy of Bureau of Land Management via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An Electric Cruise Ship | Earth Wise

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The shipping industry accounts for about 3% of global manmade greenhouse gas emissions.  In 2018, the International Maritime Organization, the UN body that regulates global shipping, set a target to cut the industry’s greenhouse gas emissions by at least half by 2050.

This goal has led to a variety of designs for eco-friendly ships, including car carriers, superyachts, and cargo ships with retractable sails.  But most of the designs still rely to at least some extent on engines that run on fossil fuels.

The Norwegian cruise ship company Hurtigruten has announced that it will build a zero-emissions electric cruise ship with retractable sails covered in solar panels.  The ship is expected to set sail in 2030.  Hurtigruten is a relatively small company, with a fleet of eight ships, each with a capacity of 500 passengers.  But the company hopes that its innovative plan will inspire the entire maritime industry.

The ship will predominantly run off of electric motors powered by 60 megawatt batteries that can be charged in port with renewable energy.  To reduce reliance on the battery, when it is windy, three retractable sails will rise out of the deck, reaching a maximum height of 164 feet.  The sails will be covered in solar panels that will generate energy to top off the batteries while sailing.

The ship will have 270 cabins to hold 500 passengers and 99 crew members.  The streamlined shape of the ship will result in less air resistance to further reduce energy use.

Hurtigruten already has a hybrid, battery-supported cruise ship and is currently in the process of converting its entire fleet to hybrid battery power.

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An electric cruise ship with gigantic solar sails is set to launch in 2030

Photo, posted January 15, 2023, courtesy of Bernard Spragg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Renewables In China | Earth Wise

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A couple of years ago, China set an ambitious goal for renewable energy capacity – which includes wind, solar, hydroelectric, and nuclear power – for it to exceed fossil fuel capacity by 2025.  According to a recent report by Reuters, China has hit this goal two years ahead of schedule.  Renewables now make up 50.9% of the country’s power capacity.

The rapid growth in renewable capacity has largely been driven by investments in wind and solar megaprojects in the sparsely populated west of the country that export power to the manufacturing centers in the east.  China’s most recent 5-year plan calls for 570 gigawatts of wind and solar power to be installed over that period, which more than doubles its installed capacity.  The plan makes use of what it called “clean energy bases”, which utilize sandy and rocky deserts, other types of barren lands, and wastelands left behind by coal mining.  The largest clean energy bases make use of vast deserts in Inner Mongolia and Gansu.

One cautionary note is that power capacity refers to the maximum amount of electricity that a power plant can produce under ideal conditions.  Thus, for example, it refers to how much electricity a solar farm can generate at noon on a cloudless day.  So, the new figures from China don’t necessarily reveal how much electricity China is actually drawing from renewables.  In reality, China still gets a great deal of its power from coal.

China is the world’s largest emitter of carbon dioxide – more than twice as much as the United States, albeit from nearly 4 times the population.  The rapid growth of renewables is at least moving that country in the right direction.

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Fossil Fuels Now Account for Less Than Half of China’s Power Capacity

Photo, posted December 2, 2015, courtesy of IBM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric Motors For Aviation | Earth Wise

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Aviation contributes about 3% of global greenhouse gas emissions.  Its carbon footprint is one of the more difficult ones to reduce.  Electrifying planes would shrink that footprint considerably, but it represents a significant technical challenge.  To date, only small all-electric planes have gotten off the ground.  The electric motors in those planes generate hundreds of kilowatts of power.  To power large planes, like commercial airliners, megawatt-scale motors are required.

A team of MIT engineers is developing a 1-megawatt motor that could be a key step towards electrifying commercial aircraft.  They have designed and tested major components of the motor and have calculated how the completed design could generate one megawatt of power at a weight and size competitive with existing small aircraft engines.

To be suitable for aircraft use, motors have to be compact and lightweight.  The more power electric motors generate, the bigger they are and the more heat they produce.  Cooling motors requires additional components that take up space and add significant weight.  The MIT motor design and associated power electronics are each about the size of a typical checked suitcase and weigh less than an adult passenger.

Once the MIT team can demonstrate an entire functional motor, the design could be used to power regional aircraft and could be the enabling element of hybrid-electric propulsion systems for jet aircraft.  Possible future configurations could make use of multiple one-megawatt motors powering multiple fans distributed along aircraft wings.

Electrification of aircraft is a slow but steady area of development and technologies such as that being developed at MIT could end up meeting the practical needs of the aircraft of the future.

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Megawatt electrical motor designed by MIT engineers could help electrify aviation

Photo, posted September 14, 2019, courtesy of Dylan Agbagni via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Decontaminating Drinking Water | Earth Wise

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At least two billion people around the world often drink water that is contaminated with disease-causing microbes.  Waterborne diseases are responsible for two million deaths each year, mostly among children under the age of five.

There are various ways to decontaminate water, including chemicals that can themselves produce toxic byproducts as well as using ultraviolet light, which takes fairly long to disinfect the water and requires a source of electricity. 

Scientists at Stanford University and the SLAC National Accelerator Laboratory have recently invented a low-cost, recyclable powder that kills thousands of waterborne bacteria every second when the water containing it is exposed to ordinary sunlight.  The discovery of this ultrafast disinfectant could be a tremendous benefit to the nearly 30% of the world’s population with no reliable access to safe drinking water.

The new disinfectant is a harmless metallic powder that works by absorbing both ultraviolet and high-energy visible light from the sun.  It consists of nano-sized flakes of aluminum oxide, molybdenum sulfide, copper, and iron oxide.  The key innovation is that when these four metallic ingredients are immersed in water, they all function together by reacting with the surrounding water and generating chemicals that quickly kill bacteria. The chemicals themselves don’t last long.  They quickly break down in the water leaving completely safe drinking water.

The nontoxic powder is recyclable.  It can be removed from water with a magnet.  It can also be reused at least 30 times.  Apart from its uses in less developed parts of the world, it could be valuable for hikers and backpackers who want to drink water from natural sources of unknown quality.

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New nontoxic powder uses sunlight to quickly disinfect contaminated drinking water

Photo, posted February 27, 2013, courtesy of Petras Gagilas 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

Water For Arizona | Earth Wise

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The Phoenix area is the fastest growing region in the country.  Arizona’s two major sources of water – groundwater and the Colorado River – are dwindling from drought, climate change, and overuse.  Officials in the state are considering a radical plan to construct a desalination plant off the Mexican coast that will take the salt out of seawater, and then pipe that water hundreds of miles, much of it uphill, to Phoenix.

The project is the brainchild of the Israeli company, IDE, which is one of the world’s largest desalination companies.  IDE has asked Arizona to sign a 100-year contract to buy water from the project. 

There are multiple complications surrounding the plan.  Desalination plants are common in California, Texas, and Florida, and in more than 100 other countries.  But the Arizona project is unusual because of the distance involved and because the state is landlocked.  The water would have to travel 200 miles and climb 2,000 feet along the way.

There is also the issue of waste brine, which is a major output of desalination plants.  In this case, the brine would flood the northern Gulf of California, potentially threatening a productive fishery.  In addition, the pipeline, as well as electrical transmission lines, would have to go through the Organ Pipe Cactus National Monument, a UNESCO biosphere reserve.

The plant would be located in Puerto Peñasco, a struggling town with its own water problems.

With booming home construction going on in the Phoenix area, the need for more water continues to grow.  Whether this plan will be approved by Arizona and by Mexico remains to be seen.

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Arizona, Low on Water, Weighs Taking It From the Sea. In Mexico.

Photo, posted September 26, 2008, courtesy of Dan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric Cars And Apartments | Earth Wise

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The transition to electric cars is underway.  People are increasingly buying them, carmakers are switching over to making them, and governments are providing incentives as well as legislating the changeover.  More and more consumers want to lower their carbon footprints and stop burning fossil fuels.  But one very large group of consumers faces an uphill battle in switching to electric cars:  people who rent their dwellings.

About one third of our country lives in rented apartments or houses.  These nearly 110 million Americans are more likely to be in the bottom half of income and net worth and are more likely to be people of color.  These people are less likely to have the spare cash to make upgrades to their property such as car chargers and may not be able to get permission from their landlords to do it anyway.

Renters face what is known as the “split-incentive problem” or the “landlord-tenant problem.”  Three-quarters of tenants in the US pay their own utility bills, so they have a strong incentive to conserve electricity, water, and gas.  Their landlords, on the other hand, have little incentive to upgrade appliances and systems to be more environmentally responsible.  Studies have shown that on average renters use 3% more energy than homeowners for this reason.

There are some landlords who are being proactive and installing facilities for charging cars on their properties.   This will undoubtedly become an increasingly sought-after feature for renters.  But in the meantime, millions of them have a more difficult time driving electric cars.  They can charge at public chargers or perhaps at work.  But at the moment, homeowners are three times more likely than renters to own an electric car.

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The coming battle between Americans who want to go electric and their landlords

Photo, posted July 22, 2022, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Keeping The Colorado River Flowing | Earth Wise

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The Colorado River supplies drinking water to 40 million Americans in seven states as well as to many Mexicans and provides irrigation to 5.5 million acres of farmland.  Electricity generated by dams on the Colorado powers millions of homes and businesses in the West.

A combination of drought, population growth, and climate change has reduced the river’s flows by a third in recent years compared with historical averages.  Further reductions could trigger a water and power catastrophe across the Western states.

California, Arizona, and Nevada all get water from Lake Mead, the reservoir formed by the Colorado at Hoover Dam.  The Interior Department determines how much water each of these three states receives.  The other states that use Colorado River water get it directly from the river and its tributaries.  Last summer, water levels in Lake Mead and Lake Powell fell enough that officials feared that the hydroelectric turbines at the Colorado’s dams would soon cease functioning.

The three states have recently struck an agreement with the federal government to take less water from the Colorado.  The reductions amount to about 13% of the total water use in the lower Colorado.  The government will pay about $1.2 billion to irrigation districts, cities, and Native American tribes for temporarily using less water.  The states have also agreed to make additional cuts to generate the total reductions needed to prevent the collapse of the river.

The agreement runs only through the end of 2026.  At that point, all seven states that rely on the river – which includes Colorado, New Mexico, Utah, and Wyoming – may well be facing a deeper reckoning.  The forces driving the decline of the Colorado are not going away.

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A Breakthrough Deal to Keep the Colorado River From Going Dry, for Now

Photo, posted June 16, 2017, courtesy Karen and Brad Emerson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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