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Airplanes and climate change

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The aviation industry is a powerful force in the global economy.  In fact, according to some estimates, the industry transports the equivalent of nearly half the world’s population every year.  But the world’s airports were largely designed for an older era – a cooler one.

As air warms, it becomes less dense, which makes it harder for airplanes to generate lift, which is the force that enables them to fly.

According to a new study by scientists from the University of Reading in the U.K., rising temperatures due to climate change may force aircraft at some airports to reduce passenger numbers in the coming decades.

The research team examined how warmer air affects aircraft performance during takeoff at 30 sites across Europe.  The study, which was recently published in the journal Aerospace, focused on the Airbus A320, which is a common aircraft used for short and medium-distance flights across Europe.

By the 2060s, the research team found that some airports with shorter runways may need to reduce their maximum take-off weight by the equivalent of approximately 10 passengers per flight during summer months.

Of the sites included in the study, Chios in Greece, Pantelleria and Rome Ciampino in Italy, and San Sebastian in Spain will be the four most affected popular tourist destinations.

Climate change is also making air travel increasingly turbulent, and the aviation industry itself remains a growing contributor to global greenhouse gas emissions. 

Taking meaningful action to curb greenhouse gas emissions, including those from the aviation industry, is one of the most crucial ways to mitigate global climate change.

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Holiday flights could carry fewer passengers as world warms

Photo, posted September 29, 2017, courtesy of Hugh Llewelyn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hydrogen-powered aviation

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

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

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

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

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

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Fueling greener aviation with hydrogen

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

Earth Wise is a production of WAMC Northeast Public Radio

Natural hydrogen

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Hydrogen is considered to be a potential substitute for conventional fossil fuels in applications where electricity cannot easily be used such as in blast furnaces, cement works, industrial heating, long-distance aviation, and shipping.  But most hydrogen is manufactured by separating it from methane, which is energy-intensive and produces carbon dioxide.  So-called green hydrogen is made by splitting water using electricity.  It is a carbon-free process if the electricity is from renewable sources, but it is pretty expensive.

A small community in Mali gets its electricity by burning natural hydrogen, which bubbles up from underground into a village well.  It has long been known that processes in the Earth’s crust can make hydrogen gas from water under certain circumstances.  But conventional wisdom has been that this occurrence is rare and that the hydrogen produced is either inaccessible or seeps away.

An increasing number of geoscientists now are convinced that there is actually an enormous quantity of hydrogen beneath the planet’s surface and that we just haven’t been looking for it in the right places, or at all, for that matter.  Some say that there could be trillions of tons of hydrogen, and more is being generated all the time.

Prospectors have recently been drilling for hydrogen in France, Australia, Morocco, Brazil, and in the United States, in Nebraska, Arizona, and Kansas.  Will extracting natural hydrogen be practical at the scale required and will it be economical?  The jury is still out on all of this, but if it turns out as proponents claim, natural hydrogen could be a very big deal.

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Natural Hydrogen: A Potential Clean Energy Source Beneath Our Feet

Photo, posted November 4, 2012, courtesy of Heather Paul 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

Electric planes: Fantasy or reality?

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Airplanes have been around for over a century, but the idea of powering them with electricity rather than with liquid fuels has been little more than a fantasy.  Over the years, billions of dollars have been invested trying to make electric planes practical.  In recent times, progress on battery technology has provided a much-needed boost for the field.

Electric planes are nowhere near becoming competitive with long distance commercial aircraft.  The weight and power requirements for such craft are far beyond what electric plane technology can do.  But electric planes could offer a very practical solution for transporting relatively small numbers of passengers over relatively short distances.

A plane built by the well-funded private company Beta Technologies has flown as far as 386 miles on a single battery charge.  The company envisions such planes to be mostly used for trips of 100 to 150 miles.  These planes could open new opportunities, like better connecting rural areas that have little or no direct air service.

Their latest model was tested on a trip between Burlington, Vermont and Florida, making multiple stops and flying through congested airspace over Boston, New York, and Washington.

Commercial versions of the planes will likely have lift rotors to take off and land like helicopters, making them deployable in a wide range of places.  Many companies are working on electric aviation, and they have backers like major automakers, major airlines, and large investment firms. 

Electric planes are not likely to replace conventional aircraft but are likely to have a meaningful impact how we move goods and services and reconnect rural parts of the country.

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Electric Planes, Once a Fantasy, Start to Take to the Skies

Photo courtesy of Beta Technologies.

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

Primary Ways To Mitigate Climate Change | Earth Wise

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The most recent report issued by the Intergovernmental Panel on Climate Change states that the world must halt the increase in greenhouse gases within three years, reduce emissions by 43% in the next seven years, and eliminate them entirely by 2050.  Otherwise, there will likely be catastrophic and irreversible impacts on the climate.

With respect to achieving these reductions, the report emphasizes decarbonizing the energy sector through electrification by replacing fossil fuels anywhere and everywhere possible.  Where that isn’t yet practical – such as in shipping and aviation – the use of biofuels and hydrogen can provide a stopgap until battery technology becomes a viable alternative.

The economics of this approach continue to improve.  Since 2010, the cost of wind, solar, and batteries has declined by as much as 85%.  In many cases, costs have fallen below those of fossil fuels.  Nonetheless, the report stresses that continuing to provide national, state, and local incentives for using renewable energy is a key factor in achieving the necessary reductions.

However, reducing emissions will no longer be enough.  This is the first major IPCC report that states that man-made carbon dioxide removal strategies will be necessary to meet the goals of the Paris Climate Agreement.  So-called natural carbon storage options, like planting trees and using farming methods that sequester carbon in soil, are also important parts of the strategy.

It is up to governments, policymakers, and investors to implement the necessary changes to mitigate climate change.  There is lots of talk about it, but it will take concerted action to avoid increasingly dire consequences.

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Report highlights affordable, available ways to mitigate climate change now

Photo, posted September 8, 2007, courtesy of Kevin Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Emissions From Shipping And Aviation | Earth Wise

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The global marine shipping and aviation industries are each responsible for about 3% of greenhouse gas emissions.  These are relatively small numbers, but as other industries decarbonize, the contributions from shipping and aviation will loom larger and larger.

In October, both of these industries made commitments to reach net zero emissions by 2050.  How can they do it?  We don’t really have the details of the technologies to be used, and neither do these industries.  But there are ideas being considered.

For both ships and planes, the solution for short-distance trips can be electrification.  Electric planes are in the works for short distances.  Battery-powered container ships are also under development.  But the electrification of longer international and intercontinental routes for both industries is very difficult.  The size and weight of batteries needed for long hauls are major challenges to overcome.

The low-carbon solution slowly being deployed in aviation is sustainable aviation fuel made from renewable sources. Longer term, green hydrogen fuel for planes may be a solution.  For shipping, hydrogen may play an even larger role.  As in the other potential uses for hydrogen, the essential requirement is to be able to produce hydrogen in a way that does not emit greenhouse gases.

There are multiple ways to move towards the decarbonization of both aviation and shipping.  Which will turn out to be the most practical and successful is not yet known.  What is essential is for both industries to follow through on their commitments to research, develop, and deploy zero-carbon solutions.  They appear to have embraced the vision for the future.  Now comes the hard work of achieving that vision.

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Shipping & Aviation Plan To Go Net Zero. How?

Photo, posted August 8, 2014, courtesy of Tomas Del Coro via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Emissions From Global Computing

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A recent study from Lancaster University in the UK has concluded that global computing is likely to be responsible for a greater share of greenhouse gas emissions than previously thought and that share is continuing to grow.

Previous calculations of the contributions from information and communications technology (or ICT) estimated that globally it accounts for 1.8 to 2.8% of total emissions.  According to the new study, these estimates likely fall short of the sector’s real climate impact because they only show a partial picture.

Prior estimates do not account for the full lifecycle and supply chain of ICT products and infrastructure.  They do not include the energy expended in manufacturing the products and equipment, the carbon cost associated with all the components in the products, and the operational carbon footprint of the companies producing those components. 

The study argues that the true contribution of ICT to global greenhouse gas emissions could be between 2.1 and 3.9%, which is more than the aviation industry.  Furthermore, the study warns that new trends in computing and ICT such as the use of big data and artificial intelligence, the so-called Internet of Things, and the use of blockchain and cryptocurrencies, risk driving further substantial growth in ICT’s greenhouse gas footprint.

It has been a commonly held believe that ICT and computing technologies lead to greater efficiencies across many other sectors, leading to savings in net greenhouse gas emissions.  According to the new study, the historical evidence indicates the opposite.  ICT has driven wide-ranging efficiency and productivity improvements, but the net result in emissions has been that they have been growing steadily.

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Emissions from computing and ICT could be worse than previously thought

Photo, posted March 13, 2018, courtesy of Flickr.

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Is Peak Oil Here? | Earth Wise

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For many years there has been talk of “peak oil”, the point at which rising world oil consumption would peak and then start declining.  Some analysts have been predicting that this could happen by the 2030s.   But the coronavirus pandemic drove a 9% slump in oil demand in 2020 that some economists are saying might never be entirely reversed.

There are three major forces driving down the world’s appetite for oil:  decarbonization of economies to meet the goals of the Paris climate agreement, declining demand for oil as renewable energy sources and electric vehicles are increasingly adopted, and detoxification as cities act to curb particulates and emissions from burning petroleum.

The largest single factor is electric vehicles.  Automobiles currently consume almost half of the world’s oil.  As of the end of 2020, there were an estimated 10 million electric cars as well as more than 600,000 electric buses and trucks.  This is still less than 1% of all vehicles, but 5% of all new cars being bought are now electric and the number is growing rapidly.  Experts estimate that nearly a quarter of global car sales will be electric vehicles by 2025 and many car manufacturers are promising to sell only electric cars within the next 10 years.

The decline in oil demand is pretty much inevitable at this point.  The main question is how quickly it will happen.  Road transport makes up 48% of global oil demand, petrochemicals account for 14%, aviation 7%, and shipping 6%.  Ultimately all these things are likely to diminish over time. 

Only time will tell, but the long-awaited arrival of peak oil may already have happened.

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Amid Troubles for Fossil Fuels, Has the Era of ‘Peak Oil’ Arrived?

Photo, posted April 14, 2019, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Banning Short Plane Flights | Earth Wise

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

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

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

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

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

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

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

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

Earth Wise is a production of WAMC Northeast Public Radio.

Aircraft Emissions And Climate Change | Earth Wise

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The aviation industry accounts for about 2.4% of global carbon dioxide emissions.  If the aviation industry was a country, it would place sixth in emissions, between Japan and Germany.

According to scientists at the University of Reading in the United Kingdom, aviation industry emissions could be reduced by simply better surfing the wind.  The researchers found that commercial flights between New York and London could have used up to 16% less fuel if they had made better use of the fast-moving winds at altitude.

The study, which was recently published in the journal Environmental Research Letters, analyzed approximately 35,000 flights in both directions between New York and London last winter.  The researchers compared how much fuel was burned during these flights to how much less fuel would have been burned by flying into or around the eastward jet stream air currents. 

They found that taking better advantage of the winds would have saved about 125 miles worth of fuel per flight on average.  The fuel saving per flight was 1.7% when flying west to New York, and 2.5% when flying east to London. 

New satellites will soon allow transatlantic flights to be tracked more accurately.  This should afford aircraft more flexibility in their flight paths, allowing them to better follow tailwinds and avoid headwinds. 

Upgrading aircraft or switching to greener fuels are two other ways that the aviation industry can reduce emissions, but those things are costly and take time to implement.  Optimizing flight paths is cheaper and offers immediate benefits.  

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Aircraft could cut emissions by better surfing the wind

Photo, posted May 16, 2011, courtesy of Cory W. Watts via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hydrogen-Powered Jetliners | Earth Wise

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Airbus, the giant European aerospace company, hopes to have hydrogen-powered commercial airliners in the sky by 2035.  Such planes would have no carbon dioxide emissions.

Greenhouse gas emissions from commercial aviation have been a rapidly increasing contribution to the global total.  Of course, the Covid-19 pandemic has drastically reduced air travel, so emissions are currently lower than they have been in a very long time.  But at some point, they will resume at previous levels and continue to increase.

Planes themselves produce over 2% of global CO2 emissions, and between the climate effects of contrails and the emissions associated with the rest of the air travel industry, commercial aviation drives about 5% of global warming.

Airbus is studying design concepts in which planes run off of hydrogen and oxygen fuel and have no carbon exhaust.   Making such planes practical and environmentally advantageous requires solving an array of complex technical challenges. 

One of the biggest challenges is that the hydrogen on the market today is considered to be “brown” rather than green, meaning that it is not a sustainably produced energy source.  Almost all hydrogen produced today comes from natural gas reforming, which results in carbon emissions.  A viable hydrogen-powered aviation technology assumes that producing hydrogen by splitting water molecules into oxygen and hydrogen using renewable energy becomes the standard source for it.

There have been test flights of small planes and drones powered by hydrogen, but Airbus expects that intensive research and development for the next five years will be required to evolve its current preliminary designs to a stage where they could be developed for future use in its product line.  It won’t happen overnight, but according to Airbus, hydrogen planes are coming.

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Airbus Hopes to Be Flying Hydrogen-Powered Jetliners With Zero Carbon Emissions by 2035

Photo, posted April 15, 2019, courtesy of Olivier Cabaret via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hydrogen-Powered Transport In Britain | Earth Wise

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The first hydrogen-powered train in the UK had its first mainline runs at the end of September.  The train, known as HydroFLEX, was developed under a project headed by the University of Birmingham under the UK government’s Department for Transport. 

Hydrogen-powered trains do not emit harmful gases but rather use hydrogen and oxygen to produce electricity, water, and heat.  The technology in the HydroFLEX train will be available by 2023 to retrofit existing diesel-powered trains and thereby de-carbonize the rail network and make train travel greener and more efficient.

The UK has ambitious plans for the use of hydrogen technology.  The Department of Transport plans to publish a master plan in January that will outline how green hydrogen could power buses, trucks, rail, maritime, and aviation transport across the UK.

The HydroFLEX trial is taking place in Tees Valley in northeastern England and the plan is for that area to become a Hydrogen Transport Hub that will include the world’s largest versatile hydrogen refueling facility.   The plans for Tees Valley involve academia, industry, and government participants.  The next stages of the HydroFLEX project are well underway with the University of Birmingham developing a hydrogen and battery-powered module that can be fitted underneath a train to allow for more space for passengers in train cars.

The UK government’s Hydrogen for Transport Program is also funding a green hydrogen refueling station and 19 hydrogen-powered garbage trucks in Glasgow, Scotland.

The UK plans to switch to a net zero economy and their current program increasingly embraces hydrogen technology to provide more sustainable, greener forms of transportation.

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UK embraces hydrogen-fueled future as transport hub and train announced

Photo, posted May 15, 2019, courtesy of Jeremy Segrott via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Jet Fuel From Acetone | Earth Wise

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Acetone is a common organic solvent.  It is used to make plastic, fibers, drugs, and other chemicals.  It is commonly used by consumers as nail polish remover.  Acetone is a manufactured chemical, but it is also found naturally in the environment in plants, among other places. There are now companies that produce acetone entirely by fermentation of plant feedstocks, such as corn.

Researchers at Los Alamos National Laboratory have now developed a process by which acetone can be converted into a fuel additive that can improve the performance of petroleum-based jet fuel, providing both environmental and economic benefits.

The process takes biomass-derived acetone and converts it to isophorone, which they produce by a process called photochemical cycloaddition that creates more complex hydrocarbons.  They then use ultraviolet light to convert the isophorone into cyclobutane, which is a type of hydrocarbon with high energy density that is suitable for aviation fuel applications.

Acetone itself is quite volatile and is unsuitable for fuel applications.  It also cannot be added directly to any fuel supply since it can dissolve engine parts and o-rings.  Cyclobutane, on the other hand, is a safer and more energy-dense fuel that can be a replacement for additives that require high-pressure hydrogen treatment in their synthesis.  Currently, most hydrogen is produced by a process that generates carbon dioxide.  The new conversion process does not result in carbon emissions.

According to the Los Alamos researchers, their process can result in a domestically generated product that will provide environmental benefits, create domestic jobs, improve U.S. energy security, and further U.S. global leadership in bioenergy technologies.

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Acetone plus light creates a green jet fuel additive

Photo, posted December 18, 2007, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Contrails And Climate Change

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The white wispy trails of condensation produced by the exhaust from aircraft engines have been the subject of a popular conspiracy theory for quite a while.  The story goes that the long-lasting condensation trails are actually “chemtrails” composed of chemical or biological agents left in the sky by aircraft and are intentionally sprayed for a variety of nefarious purposes undisclosed to the general public.  This story, of course, is nonsense.

But while contrails are not deliberate efforts to modify weather, control population, manipulate psychology, or any of the other bizarre things attributed to them, it turns out that they are having unfortunate effects on the climate.

It turns out that contrails are creating an often-invisible thermal blanket of cloud across the planet that has a significant effect on atmospheric temperatures.  Contrails are essentially human-made clouds that form above 25,000 feet where the air is moist and colder than -40 degrees Celsius.  At times, contrails stick around in the sky, either as tight, white lines like chalk marks, or by spreading to create thin layers of ice clouds.  At any one time, contrail-created clouds cover more than half a percent of global skies.

Research has shown that when contrails are around, nighttime temperatures can go up appreciably.  After 9/11, when all U.S. flights were grounded for three days, the difference between daytime and nighttime temperatures actually increased by about 3 degrees Fahrenheit because nights were cooler.

The effects of aviation on climate, both from the CO2 emissions from aircraft engines and from these contrail effects are becoming an increasingly important issue. To complicate matters further, as aircraft engines become more efficient, they will create more, whiter, and longer-lasting contrails.

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How Airplane Contrails Are Helping Make the Planet Warmer

Photo, posted May 15, 2012, courtesy of Mike Lewinski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Giant Solar Farm In Dubai

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Like many places in the Middle East, Dubai made its fortune from oil.  But the Emirate’s oil resources are limited, and its economy has evolved in other directions.  Today, oil provides less than 5% of Dubai’s revenues; its economy relies on revenues from trade, tourism, aviation, real estate, and financial services.

Dubai is also away from fossil fuels to meet its energy needs. A monumental construction project is underway deep within Dubai’s desert interior which will be the largest solar energy facility in the world.

The Mohammed Bin Rashid Al Maktoum Solar Park – named after Dubai’s ruler – has been under development for 7 years.  Total investment in the project will be nearly $14 billion when it is completed in 2030.  It will have a total capacity of 5,000 megawatts, enough to power 1.3 million homes.  Only some large hydroelectric power plants, the largest nuclear power plants, and a couple of Asian coal plants have more generating capacity.

Phases one and two of the project are already complete and feature more than 2 million solar panels.  Phase three – well along the way in construction – will add another 3 million solar panels and should be completed next year.

Phase four will not involve solar panels but instead will make use of the world’s tallest concentrated solar power tower.  It will use mirrors to focus sunlight at the top of the tower to heat up molten salt that will power steam turbines to generate electricity and will be able to operate long after the sun goes down.

Currently, the Tengger Desert Solar Park in China is the largest photovoltaic park in the world, but a colossal farm in India will take its place in a few years.  Big solar is getting bigger all the time.

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$13.6B record-breaking solar park rises from Dubai desert

Photo, posted December 15, 2018, courtesy of Anoop S. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hybrid-Electric Aircraft

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The commercial aviation industry is a major source of carbon dioxide emissions and, as other industries try to move towards decarbonization, its share is getting larger.  But reducing emissions from aircraft is challenging because powering planes without burning fossil fuel is hard to do.

The biggest problem is that powering aircraft with electric motors instead of fossil fuel motors requires so much energy that the batteries needed to supply it become impractically heavy.  While research goes on to develop lighter-weight batteries, an interim concept may pay dividends.

Just as hybrid cars represent a stepping stone towards full electrification, hybrid-electric aircraft may be a way to obtain substantial reductions in aircraft emissions.  The idea is to use battery-powered electric motors to power planes, but to greatly reduce the capacity requirements of the batteries by having an on-board fossil-fuel generator to charge the batteries and supply additional needed power.

A study by the University of Illinois looked at the potential emissions reductions for hybrid-electric aircraft taking into account the emissions associated with generating the electricity that charges the batteries in the plane.  The requirements in the study were that the plane needs to be able to carry the same number of passengers and travel the same distance as current aircraft. 

The results were that a drivetrain that gets 50% of its power from battery charge reduced emissions by about 50% over the full lifecycle of the plane.

As batteries get lighter and the electric grid gets greener, the possibility of making major reductions in aircraft carbon emissions looks increasingly realistic.  But there is a long way to go.

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Study Examines Commercial Hybrid-Electric Aircraft, Reduced Carbon Emissions

Photo, posted September 26, 2014, courtesy of Jeff Turner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plant-Based Jet Fuels

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The global aviation industry uses a whole lot of fuel:  more than 5 million barrels a day.  It is an incredibly energy-intensive industry and almost all of its energy comes from petroleum-based fuels.

While other large energy sectors such as electric power, ground transportation and commercial buildings have well-defined pathways to adopting renewable energy sources, the aviation industry does not have such a straightforward way to make a transition to sustainability.  Electrifying planes using batteries or fuel cells is very challenging for a number of reasons, notably the weight restrictions on aircraft.  So liquid biofuels as replacements for petroleum-based fuels remain the most promising approach.

A new study at the Lawrence Berkeley National Laboratory concludes that sustainable plant-based biofuels could provide a competitive alternative to conventional petroleum fuels if current development and scale-up initiatives are successful.

Multidisciplinary teams based at the Department of Energy’s Joint BioEnergy Institute are focused on optimizing each stage of the bio-jet fuel production process.  This includes bioengineering ideal source plants and developing methods for efficiently isolating the carbohydrates in non-food biomass that bacteria can digest and bioconvert into fuel molecules.

The critical issue is cost.  The theoretical cost of bio-jet fuel has come down dramatically in recent years but is still around $16 a gallon.  The cost of standard jet fuel is about $2.50 a gallon.  So, the real challenge is bridging that gap.

Reducing the cost of the fuel could come both from the material and process improvements that are underway as well as by finding ways to turn the leftover lignin residuals from the bioconversion process into valuable chemicals. 

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Bright Skies for Plant-Based Jet Fuels

Photo, posted March 28, 2009, courtesy of Yasuhiro Chatani via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Air Travel And Global Warming

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Air travel is pretty carbon intensive.  For those of us who take plane trips, it represents a substantial part of our individual carbon footprints. It isn’t that plane travel is inefficient fuel-wise on a miles-per-gallon-per-passenger basis compared with driving, for example.  It is just that we go so much farther on planes.   Currently, aviation accounts for only a few percent of overall carbon emissions, but that is changing for two reasons.

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