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Better Plastic Recycling | Earth Wise

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Many of us are careful to put our plastic trash into the appropriate recycling bins hoping that we are helping to stem the global tide of plastic waste.  But many plastics are not recyclable at all and recycling those that are is not even always a good thing.  Breaking down plastics can generate polluting microplastics that are themselves a major environmental problem.  And perhaps the biggest problem for recycling efforts is that they are not cost effective and generally incur huge losses.

Chemical engineers at the University of Wisconsin-Madison recently published a study in the journal Nature outlining a new technique for turning low-value waste plastic into high-value industrial chemicals. 

The technique makes use of two existing chemical processing techniques.  The first is pyrolysis, which is high-temperature heating in an oxygen-free environment.  Heating waste plastic in this way produces pyrolysis oil, a liquid mix of various compounds that includes large amounts of olefins.  Olefins are simple hydrocarbons that are a central building block of many chemicals and polymers.  Olefins are most often produced by energy-intensive processes like steam cracking of petroleum. 

The UW-Madison process takes the olefins and subjects them to a process called homogenous hydroformylation catalysis, which converts them into aldehydes, which can then be further reduced into important industrial chemicals. 

The payoff is that the process can take waste plastics, which are only worth about $100 a ton, and turn them into high-value chemicals worth $1,200-$6,000 a ton.  If the process can be optimized and otherwise made ready for industrial-scale use, it would be a real game-changer in the battle against plastic waste.

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New recycling process could find markets for ‘junk’ plastic waste

Photo, posted September 16, 2015, courtesy of Oregon State University 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

SuperHot Rock Geothermal Energy | Earth Wise

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The United States in a world leader in geothermal energy.  There are geothermal power plants in 7 states which produce about half a percent of the country’s electricity.  Conventional geothermal energy plants take advantage of natural underground sources of heat such as geysers, superheated underground reservoirs, and such.  Steam from these sources activates generators that produce electricity.  However, there are not many places where these systems can be built.

More recently, there has been growing interest in so-called enhanced geothermal systems (or EGS systems) which generate geothermal electricity without the need for natural convective hydrothermal sources.  There are many places where underground heat is available but no existing water taps into it.  The idea is to tap into the earth’s deep geothermal resources by fracturing rock and pumping water into it to be heated. 

AltaRock Energy, a Seattle-based company that develops EGS technology, has recently announced the results of a comprehensive technical and economic feasibility study demonstrating the potential benefits of an EGS system that could use high-temperature impermeable rock deep below the Newberry Volcano near Bend, Oregon.  The so-called SuperHot rock there is in excess of 750 degrees Fahrenheit.

Based on measurements at the site and modeling, the study determined that an EGS system at the site could cut the levelized cost of electricity in half when compared with a conventional EGS resources at 400-500 degrees. 

The company expects that the study will pave the way for the development of the first SuperHot Rock geothermal resource in the United States.

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AltaRock clears hurdle in quest for ‘next generation’ geothermal resource

Photo, posted June 26, 2018, courtesy of David Fulmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Carbon Capture Technique | Earth Wise

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Carbon dioxide emissions by electricity generating plants, fossil-fuel burning vehicles, and industry produce about 2/3 of the greenhouse gases driving climate change.  Without decreasing these emissions, the earth will continue to get warmer, sea levels will continue to rise, and the world will face more droughts, floods, wildfires, famine and conflict.

Electrification of vehicles and reliance upon renewable energy sources will ultimately drastically reduce the use of fossil fuels and the resultant emissions, but that transition may take too long to reverse the direction of climate change.  In the meantime, there is a great need to find effective and efficient ways to capture emissions from fossil fuel plants. 

Recent research at the University of California, Berkeley, Lawrence Berkeley National Laboratory, and ExxonMobil has developed a new technique for carbon capture.  The technique makes use of metal-organic framework (or MOF) technology.  An MOF, modified with nitrogen-containing amine molecules, captures CO2 and then low-temperature steam is used to flush out the CO2 either to be used or sequestered underground.

Experiments demonstrated the technique to have a six-times greater capacity for removing CO2 from the flue gas of a refinery than current amine-based technology.  It selectively removed 90% of the emitted CO2. 

There is a relatively limited market for captured CO2, so power plants using the capture technology would likely pump the CO2 into the ground, or otherwise sequester it.  The cost of doing this sort of emission scrubbing would have to be facilitated by government policies, such as carbon trading or a carbon tax, which would provide the necessary economic incentive for doing carbon capture and sequestration.

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New technique to capture CO2 could reduce power plant greenhouse gases

Photo courtesy of UC Berkeley.

Earth Wise is a production of WAMC Northeast Public Radio.

Energy Intensity

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Every stage of civilization is characterized by its use of energy.   From burning wood to steam engines to our electrified society, energy is behind everything we do.  Over time, human society has become increasingly energy intensive.  As our standards of living have improved and as we overcome the effects of weather – either cold or warm – it takes more and more energy to live the lives we lead.

[Read more…] about Energy Intensity

Green Steam

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Many of the world’s biggest cities have miles of underground pipes built decades ago that provide district energy.   District energy systems use a central plant to produce steam, hot water or chilled water that is then piped underground to individual buildings for space heating, domestic hot water heating and air conditioning. As a result, individual buildings served by a district energy system don’t need their own boilers or furnaces, chillers or air conditioners.

[Read more…] about Green Steam

WAMC Northeast Public Radio

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