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Moisture swing carbon capture

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As the world grapples with limiting the amount of carbon dioxide in the atmosphere, there is a growing need to capture the carbon dioxide that is emitted as well as preventing it from being emitted in the first place.  Carbon capture can be accomplished at the source of emissions (such as power plants) or it can be done by taking it out of the atmosphere.  The latter is called “direct air capture”.

It is not at all clear whether direct air capture can be accomplished on a scale that would really make a difference and at an acceptable cost either in dollars or energy expended.  But if it can be done that way, it would be a major tool in combatting climate change.

Direct air capture technology generally makes use of sorbent materials whose capacity to capture carbon dioxide and later release it is a function of temperature.  The process requires significant amounts of energy to release the carbon dioxide that has been captured. 

New research from Northwestern University makes use of the “moisture-swing” technique which uses materials whose ability to capture and release carbon dioxide depends on humidity rather than temperature.  While it takes some amount of energy to humidify the volume of air containing the sorbent material, it is very small compared to temperature-driven systems. 

There are many groups working with moisture-swing technology, but the Northwestern Group has identified a number of new sorbent materials with superior properties.

The fundamental questions of scalability and cost remain, but moisture-swing is a promising approach to direct air capture.  If carbon dioxide can be pulled out of the atmosphere in large volumes, it can be concentrated and stored or converted into useful products.

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Pulling carbon dioxide right out of the air

Photo, posted May 15, 2020, courtesy of James Watt 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

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

Chatbots Are Thirsty | Earth Wise

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We hear a lot about artificial intelligence these days.  ChatGPT has found its way into education, technology, and many other aspects of life.  It and its brethren are a source of fascination, enthusiasm, and even fear.  Many of us have given queries to the bot to see what kind of results we can obtain.  But a recent study has found out something about AI systems that we probably didn’t know – they use up lots of fresh water.

According to researchers at the University of California, Riverside, running a few dozen queries on ChatGPT uses up about half a quart of fresh water from already overtaxed reservoirs.

Running artificial intelligence systems like ChatGPT relies on cloud computations done in racks of servers in warehouse-sized data processing centers.  Google’s data centers in the U.S. alone consumed nearly 3.5 billion gallons of fresh water in 2021 in order to keep their servers cool.

Data processing centers consume water in two ways.  They often draw much of their electricity from power plants that use large cooling towers that convert water into steam emitted into the atmosphere.  In addition, the servers themselves need to be cooled to keep running and are typically connected to cooling towers as well.

It isn’t going to be easy for AI systems to reduce their water use.  The study’s authors noted that people make use of AI at all hours of the day and night.  But a significant amount of AI activity is actually the training of the systems.  That could be scheduled for the cooler hours, when less water is lost to evaporation.

In an era of scarce fresh water and droughts, it is important to make AI less thirsty.

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AI programs consume large volumes of scarce water

Photo, posted May 22, 2023, courtesy of Jernej Furman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Minimizing The Impact Of EVs On The Grid | Earth Wise

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Two current trends are the increasing reliance on renewable sources in the electric grid and the increasing use of electric vehicles.  According to some projections, these trends could lead to the need for costly new power plants to meet peak loads in the evening when cars are plugged in to charge.  Overproduction of power from solar farms during the daytime would require expanded energy storage capacity so as not to waste all that generating capacity.

A new study by MIT researchers has found that it is possible to mitigate or eliminate these problems without the need for advanced technological systems and complex infrastructure.  The key elements of the strategy are the strategic placement of charging stations and the practice of delaying the onset of home charging.

Better availability of charging stations at workplaces could help to soak up peak power being produced at midday from solar power installations.  In general, placing of charging stations in strategic ways, rather than letting them spring up just anywhere, could make a big difference.

Delaying home charging to times when there is less electricity demand could be accomplished with the use of a simple app that would estimate the time to begin the charging cycle so that it finishes charging just before the car is needed the next day.  Since different people have different schedules and needs, by delaying the onset of charging appropriately, not everyone will be charging at the same time, and therefore the peak in demand would be smoothed out.

There are substantial government funds earmarked for charging infrastructure and creating that infrastructure in suitably strategic ways could make a big difference in supporting EV adoption and supporting the power grid.

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Minimizing electric vehicles’ impact on the grid

Photo, posted July 2, 2020, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Renewables’ Growing Share | Earth Wise

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Not long ago, many states across the country were setting goals to obtain 20% of their electricity from renewable sources. For a few states, like New York and Washington, ample amounts of hydropower made 20% an easy target.  But for many others, 20% seemed like a very ambitious objective.

Things have certainly changed.  According to the latest monthly Short Term Energy Outlook, a report from the federal government, the combination of wind, solar, and other renewable sources will exceed one-quarter of the country’s generation by 2024.

Renewables are already at 24% of U.S. electricity generation and are expected to rise to 26% by next year.  Coal, which used to be the largest source of electricity, will continue to drop from its current 18% to 17% by next year.  Overall, renewables passed coal for the first full year in 2020.  Coal staged a bit of a comeback in 2021, but has once again resumed its decline.  Many coal-fired power plants continue to close, and there are not new ones being built because of diminishing economic benefits as well as concerns about emissions.

The largest source of electricity generation continues to be natural gas at 38%, but that number is also expected to slowly decrease over time. The growth in renewable energy is coming from wind and solar power.  Two-thirds of that growth is from solar and one-third is from wind. 

Together, wind and solar power will add up to 18% of the country’s electricity supply.  The government still tracks them lumped together as renewables, but both are so large and growing so quickly that the Energy Information Agency is likely to soon start tracking them as separate categories.

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Renewables Projected to Soon Be One-Fourth of US Electricity Generation. Really Soon

Photo, posted April 18, 2011, courtesy of Allan Der 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

Solar Parking Lots In France | Earth Wise

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France has passed legislation that will require all parking lots with more than 80 spaces to be covered over by solar panels.  This is part of a broader effort to put solar panels on vacant lots, empty land alongside roadways and train tracks, and even some farmland.  The overall program would add 11 gigawatts of solar power to the French electricity grid.

The legislation applies to both new and existing parking lots.  Owners of parking lots with more than 400 spaces would have 3 years to comply, while owners of lots with 80 to 400 spaces would have five years.

To produce 11 gigawatts of solar output, about half a percent of France’s urban land would need to be covered with solar panels.  This is quite a bit, but not an insurmountable obstacle.  Parking lots, however, could only provide a fraction of what is needed.  It would take something like 8 million parking spaces covered with solar panels to produce that much power.  That is probably at least twice as many as France has.

Several countries, most notably Germany, already have mandates for new construction to incorporate renewable energy.  This includes solar panels, biomass boilers, heat pumps, and wind turbines.  Many parking lots in southern Europe already have sunshades over them, which would make it pretty easy to install solar panels.  This is much rarer in cooler countries.

France is pursuing this policy to reduce its dependence on nuclear power, which currently provides 70% of the country’s electricity.  Apart from the general trend of opposition to nuclear power, reliance upon it during increasingly common droughts is problematic as the power plants require significant amounts of water to operate.

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France’s plan for solar panels on all car parks is just the start of an urban renewable revolution

Photo, posted February 11, 2008, courtesy of Armando Jimenez / U.S. Army Environmental Command via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

It Really Is Greenhouse Gases | Earth Wise

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The scientific consensus that human-generated carbon dioxide is changing the climate began to form in the 1980s. 

For a long time, the changes to the climate were simply denied.  After a while, as those changes became increasingly hard to ignore, the argument shifted to the changes being real but not caused by anything people are doing.  The multi-trillion-dollar fossil fuel industry was strongly motivated to focus attention away from the association between carbon dioxide and climate change.

The greenhouse gas effect has been known since the 19th century.  It isn’t just real; it is essential to life on earth.  Without sufficient levels of carbon dioxide in the atmosphere to trap some of the sun’s heat, the earth would be an ice planet incapable of supporting much in the way of life.  But there can be too much of a good thing.

Naysayers continue to grasp at alternative explanations for the warming planet rather than the inconvenient truth.  Some people try to claim that it is the release of heat from all our energy-generating activities -power plants, heaters and air conditioners, vehicles, and so on – that is warming the planet.

That issue has been studied in detail.  Human activity does generate a lot of heat and, technically speaking, that heat does help warm the planet.  However, the sun dumps 10,000 times more heat on the earth than all of human energy production added together.  Just the normal fluctuations in solar energy are 10 times larger than everything we do put together.

What is increasingly warming the planet is not the continuing energy striking the earth; it is primarily the fact that growing levels of greenhouse gases in the atmosphere are trapping more and more of that heat and preventing it from escaping into space.

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Integrating anthropogenic heat flux with global climate models

Photo, posted August 25, 2009, courtesy of Gerald Simmons via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

New York Bans Some Crypto Mining | Earth Wise

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Crypto mining, the arcane process by which cryptocurrencies are generated, is incredibly energy-intensive.  As of this past summer, global electricity usage for the activity is as much as 240 billion kilowatt-hours per year, which is more than many entire countries use (for example Australia and Argentina.)  Crypto mining consumes as much electricity as all the conventional computer data centers in the world.

All that energy usage is problematic for the environment, but a growing practice has made it far worse.  Crypto miners have been re-powering decommissioned fossil fuel power plants to produce electricity strictly for mining operations.  Doing so eliminates the climate benefits achieved by shutting down those plants.

The New York State Legislature passed a bill in June that would place a two-year moratorium on permits to re-power fossil fuel plants.  It does not prevent crypto mining from existing generation sources.  The bill had sat on the governor’s desk until after the recent election.   But in late November, Governor Hochul signed the bill despite considerable lobbying against it.

The temporary ban was heavily opposed by cryptocurrency industry groups, to no surprise.  While some states actually offer tax incentives to lure crypto mining operations, supporters of the legislation hope that New York’s action may cause others to follow its lead and stop the reactivation of old fossil fuel plants.

The two-year moratorium will allow time to properly evaluate the impact of the crypto mining industry on the state’s climate goals.  It is pretty obvious that reactivating old, retired fossil fuel power plants as an energy source is a move in the wrong direction.

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New York Enacts 2-Year Ban on Some Crypto-Mining Operations

Photo, posted February 27, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hybrid Renewable Energy Plants | Earth Wise

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Hybrid renewable energy systems combine multiple renewable energy and/or energy storage technologies into a single plant.  The goal is to reduce costs and increase energy output relative to separate systems taking advantage of common infrastructure and the ability of one renewable energy source having appreciable output while a second one might not at a particular time.

Recently, the largest hybrid renewable power plant in the United States was completed in rural Oregon.  The Wheatridge Renewable Energy Facility combines a wind farm, a solar array, and battery storage.

Plants that include just solar power and energy storage are also called hybrid plants, but the Wheatridge Facility is special because it includes wind power.  The facility comprises a 200-megawatt wind farm, a 50-megawatt solar array, and a 30-megawatt battery system capable of providing power for four hours.  The combined system can provide for the electricity needs of about 100,000 homes.

There are about 140 projects in the United States that combine solar and storage.  There are 14 that combine solar and wind.  There are only four plants – with the completion of Wheatridge – that have wind, solar, and storage.  

Wind and solar energy are generally complementary technologies.  Wind is usually strongest at night while solar, of course, is a daytime source of energy.  Solar and wind plants don’t need to be close together to take advantage of this, but hybrid projects benefit from needing only one grid connection and one lease for land.

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A Clean Energy Trifecta: Wind, Solar and Storage in the Same Project

Photo, posted December 27, 2015, courtesy of Gerry Machen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfire Smoke And Air Quality | Earth Wise

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According to a new study published by Stanford University, the average number of people in the U.S. exposed to unhealthy levels of airborne particulates at least one day a year has increased 27-fold over the last decade as a result of wildfires.

Millions of Americans are now routinely exposed to plumes of wildfire smoke that sometimes travel thousands of miles across the country.  Accumulations of deeply unhealthy air have emerged mainly in the West, where increasingly intense wildfires have become all too common.  Six of the seven largest wildfires in California recorded history have occurred since 2020.

Wildfire smoke has resulted in school closures, flight postponements, and even cancelled concerts.  Overall, the regression in air quality has undone much of the clean air progress that has taken place since the advent of the Clean Air Act in 1970.

Wildfire smoke has added about 5 micrograms of PM 2.5 particles per cubic meter of air on average in many places in the West.  This is a substantial increase from national levels, which are a total of about 10 micrograms per cubic meter and mostly result from emissions from cars, trucks, and power plants.

A decade ago, fewer than 500,000 Americans were exposed to any days of an air quality index of 100 or more due to smoke, which is a level that is deemed unhealthy.  In 2020, 25 million Americans were in areas with such levels at least one day during the year.

Ordinarily, if people don’t live near a highway or power plant, their air quality is likely to be pretty good.  But incursion from wildfire smoke is changing that, and the trend is likely to increase.

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Number of Americans Exposed to Harmful Wildfire Smoke Has Increased 27-Fold

Photo, posted August 19, 2013, courtesy of Mike Lewelling / National Park Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Air Pollution: The Greatest Danger | Earth Wise            

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The effort to reduce and ultimately eliminate the use of fossil fuels has largely been driven by the potentially catastrophic consequences of global climate change.  The need to stop dumping greenhouse gases into the atmosphere has become increasingly urgent.  But there is an equally compelling reason to stop burning fossil fuels.  According to a study published in the journal Lancet Planetary Health, outdoor air pollution is “the largest existential threat to human and planetary health.”

Pollution of various types was responsible for an estimated 9 million deaths around the world in 2019.  Half of those fatalities – 4.5 million deaths – were the result of outdoor air pollution coming from vehicles and industrial sources like power plants and factories.

The number of deaths attributed to air pollution has increased by 55% just since the year 2000.

The growth in air pollution deaths has offset a decline in deaths from other pollution sources that especially affect people living in extreme poverty, such as indoor air pollution and water pollution.  Overall, countries with lower collective incomes tend to bear a disproportionate share of pollution deaths.  Roughly 16% of deaths around the world are attributable to pollution, also resulting in more than $4 trillion in economic losses.

The peer-reviewed study was produced by the 2017 Lancet Commission on Pollution and Health.  The study notes that despite the enormous health, social, and economic impacts of pollution, preventing it is largely overlooked in the international development agenda.  The study calls upon governments, businesses, and other entities to abandon fossil fuels and adopt clean energy sources.

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Study Identifies Outdoor Air Pollution as the ‘Largest Existential Threat to Human and Planetary Health’

Photo, posted November 4, 2019, courtesy of Ninara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Weaning Off Fossil Fuels | Earth Wise            

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We recently talked about California producing 97% of its electricity from renewables on one sunny afternoon in April.  On May 8th, the state produced enough renewable electricity to meet 103% of consumer demand.  These sorts of records are likely to be increasingly commonplace in the spring when the weather is still fairly mild.

But even while renewables were producing more electricity than California needed, natural gas power plants in the state were still running.

Turning off the gas power plants is not possible.  The reason is that as the sun sets and solar farms stop producing power, California has to quickly replace the power with electricity from other sources.  Natural gas plants are massive industrial facilities that cannot be turned on and off rapidly.  Some take as many as 4 to 8 hours to switch on.  Operators back them down as far as they can go, but even when there is plenty of solar power during the day, natural gas plants are still running.

The state is rapidly building huge battery storage projects as an alternative to gas plants, but so far, they are still only a small fraction of what is needed.   Wind power is another part of the solution along with hydropower.  California imports some power from other states as well and, in fact, also exports power when there is excess.  But keeping the energy system balanced and stable is an ongoing challenge.

California is building huge amounts of solar, huge amounts of wind, and huge amounts of energy storage, which should get the state to at least 90% of the way to a clean grid.  It’s the last 5-10% that is much harder to accomplish before natural gas is no longer part of the energy system.

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California just ran on 100% renewable energy, but fossil fuels aren’t fading away yet

Photo, posted January 10, 2014, courtesy of F.G. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Better Way To Capture Carbon | Earth Wise

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The goal of carbon capture and storage technology is to remove carbon dioxide from the atmosphere and safely store it for the indefinite future.  There are existing industrial facilities that capture carbon dioxide from concentrated sources – like the emissions from power plants.  The technology currently captures and stores only about a tenth of a percent of global carbon emissions.

Most existing CCS technologies use chemical binders to trap carbon dioxide quickly and efficiently, but they are extraordinarily energy intensive as well as expensive.

Researchers at the University of Colorado Boulder have developed a new tool that could lead to more efficient and cheaper ways to capture carbon dioxide directly out of the air.  The tool predicts how strong the bond will be between carbon dioxide and a candidate molecule for trapping it – that is, a binder.  This new electrochemical diagnostic tool can be used to identify suitable molecular candidates for capturing carbon dioxide from everyday air.

Current carbon capture technologies are very expensive at the scale required to be able to turn the captured CO2 into useful substances, such as carbonates – which are an ingredient in cement – or formaldehyde or methanol, which can be used as fuels.  Making useful materials out of the captured CO2 is an important way to offset the cost of capturing it that merely storing it away does not permit.

The new electrochemical analytical tool developed by the Colorado researchers offers the potential for identifying binders that will be more efficient and less expensive, thereby making direct air carbon capture a realistic part of the efforts to address climate change.

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New method could lead to cheaper, more efficient ways to capture carbon

Photo, posted October 25, 2015, courtesy of Frans Berkelaar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Pollution Into Cash | Earth Wise     

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Power plants and other industrial facilities are a major source of carbon emissions.  There are a variety of techniques under development to prevent those emissions by capturing them rather than releasing them into the atmosphere.  All of them add costs to the functioning of the facility.  A good way to offset those costs is to convert the emissions into useful products, ideally making it profitable to capture emissions.

Engineers at the University of Cincinnati have developed an electrochemical system that converts carbon dioxide into ethylene, which is a chemical used in a wide range of manufacturing.  Ethylene has sometimes been called “the world’s most important chemical”.  It is used in many kinds of plastics, textiles, and the rubber found in tires and insulation. It is also used in heavy industry such as steel and cement plants as well as in the oil and gas industry.

The Cincinnati process is a two-stage cascade reaction that converts carbon dioxide to carbon monoxide and then into ethylene.  It is based on the underlying principle of the plug-flow reactor that is used for variety of production applications.  The study, published in the journal Nature Catalysis, demonstrates that the process has high ethylene selectivity – meaning that it effectively isolates the desired compound – as well as high productivity – meaning that it makes a lot of it.  The system will take more time to become truly economical, but the researchers are continuing to make progress on that front with improved catalysts.

The researchers believe that this technique can reduce carbon emissions and make a profit doing it.  Power plants and other facilities emit a lot of carbon dioxide.  With this process, it may be possible to capture it and produce a valuable chemical.

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Conversion process turns pollution into cash

Photo, posted February 27, 2018, courtesy of Cyprien Hauser via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenhouse Gas Removal And Net Zero | Earth Wise

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Reducing the amount of greenhouse gas emissions can slow the progress of global warming but only reaching and sustaining net zero global emissions can halt the progress of climate change.

The move to renewable power and the use of electric transport are substantial and essential ways to reduce emissions.  But even if these transitions take place on a rapid timescale, they will not eliminate all emissions.  Many industrial activities and, especially, agriculture will continue to contribute substantial greenhouse gas emissions.   There are efforts to reduce the contributions of these things, but there are no zero-emission substitutes for most of them.

As a result, actually removing CO2 from the atmosphere once it is there is essential to achieve net zero emissions.  If greenhouse gas removal can be scaled up sufficiently, it opens the option of going “net negative”, which would be the ideal way to mitigate and, better still, reverse the effects of climate change.

There are multiple approaches to carbon dioxide removal.  Some are natural, involving ways of capturing and storing carbon in trees, biochar, and peatlands.  Others are technological.  An example is the system that has just gone into operation in Iceland that uses fans, chemicals, and heat to capture CO2 and then mineralize it in volcanic rock.   Another is a system being tested in the UK that captures CO2 from growing biomass and pipes it to storage under the North Sea.

Much of the attention on carbon capture technology is aimed at trapping the emissions from fossil fuel power plants, but the need to remove carbon dioxide that has entered the atmosphere in other ways is ultimately far greater.

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CO2 removal is essential to achieving net zero

Photo, posted August 17, 2013, courtesy of Joshua Mayer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Direct Air Capture | Earth Wise

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There is a lot of interest in carbon capture and sequestration (or CCS) in the context of trapping the carbon dioxide emissions from power plants and industrial facilities.  The fossil fuel industry is especially enthusiastic about the potential for continuing to burn fuels without harming the environment.  Apart from the technical challenges, there is the looming problem of CCS adding significant costs to power generation that is already losing the economic battle to renewable sources.

Direct air capture is a different matter.   This is the idea of actively taking CO2 out of the atmosphere.  This already happens by natural means such as sequestering it in soil or forests.  But there is considerable work going on aimed at developing technology to capture atmospheric carbon dioxide in massive quantities.

This September marks the opening of a new project called “Orca” in Iceland, which will, for the time being, be the largest direct air capture system in the world.  Once it is running around the clock, Orca will remove up to 4,000 metric tons of CO2 from the atmosphere each year.

Even larger DAC plants – one in the southwestern U.S and another in Scotland – are planned to come online in the next few years.

Ultimately, the question is whether direct air capture is feasible at large enough scale and affordable cost.  The numbers are daunting.  Society releases over 30 billion metric tons of carbon dioxide into the atmosphere each year.  Removing significant amounts of that with DAC technology is an enormous challenge.  Eliminating emissions remains the most practical way to mitigate the effects of climate change.

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The Dream of Carbon Air Capture Edges Toward Reality

Photo, posted November 10, 2017, courtesy of Governor Jay and First Lady Trudi Inslee via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving Water At Power Plants | Earth Wise

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Nearly 40% of all the water taken from lakes, rivers, and wells in the U.S. isn’t used for agriculture, drinking, or sanitation.  It is used to cool power plants that produce electricity by burning fossil fuels or with nuclear reactors.   Two-thirds of these power plants use evaporative cooling, which produces huge white plumes billowing from cooling towers.

A new company using technology developed at MIT has the goal of reducing the water needs of power plants and helping to alleviate water shortages in areas where power plants strain the capacity of local water systems.

The technology is relatively simple in principle but developing it to the point where it can be applied at full scale at industrial power plants was a greater challenge. 

The basic idea is to capture water droplets from both natural fog and from the plumes from power plant cooling towers.  The MIT researchers had to improve the efficiency of fog-harvesting systems, which previously captured only 1-3% of the water droplets that pass through them.  They found that water vapor collection could be made much more efficient by zapping the tiny droplets of water with an ion beam, giving them a slight electric charge, thereby making it easy to capture them with the metal mesh of the harvesting system.

The system can essentially eliminate cooling tower plumes and produce large quantities of high-purity water in the process, which has uses at many power plants.  The new company, called Infinite Cooling, has arranged to install their equipment on two operating commercial power plants later this year.  They expect the system to reduce the overall need for water by 20%.

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Vapor-collection technology saves water while clearing the air

Photo, posted March 5, 2019, courtesy of Sam LaRussa via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Pandemic And Global Temperatures | Earth Wise

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The early months of the Covid-19 pandemic last year saw dramatic reductions in travel and many forms of commerce.  With much of human activity greatly curtailed, greenhouse gas emissions were greatly reduced.   And yet, all of that did not slow down global warming: 2020 ended up tied with 2016 as the warmest year on record and atmospheric greenhouse gas levels reached a new high.

In order to understand how this came about, it is necessary to understand the complex climate influences of different types of emissions from power plants, motor vehicles, industrial facilities, and other sources.  The fact is that some types of pollution actually have a cooling effect rather than contributing to global warming.

Tiny industrial pollution particles called aerosols actually make clouds brighter, causing them to reflect away more solar heat from the surface of the planet.   During the drastic shutdown last year, the biggest emissions decline was from the most polluting industries.  The reduction of aerosols had immediate, short-term effects on temperatures.  These types of pollutants are very bad for human health, but when they are present, they do have the effect of reducing temperatures.

It is important to keep in mind that carbon dioxide spreads through the Earth’s atmosphere and stays there for a century or more, trapping heat on a global scale.  Industrial aerosols stay relatively concentrated in the region where they are emitted and are often removed by rain and winds within a few weeks.  So, their cooling effect doesn’t spread very far or last very long.

Overall, the initial pandemic slowdown probably didn’t have any real long-term impact on the climate but over the short term, the effects were not as simple as one might expect.

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Covid-19 Cut Gases That Warm the Globe But a Drop in Other Pollution Boosted Regional Temperatures

Photo, posted July 7, 2020, courtesy of Joey Zanotti via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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