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Solar thermochemical hydrogen

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For decades, there has been talk of the hydrogen economy in which hydrogen would take the place of fossil fuels in a wide range of domestic and industrial applications.  Over time, hydrogen’s potential advantages in some applications have diminished but it is still seen as perhaps the most promising way to decarbonize long-distance truck, ship, and plane transportation as well as many heavy-duty industrial processes.

Hydrogen is the most common element in the universe, but here on Earth, it is tightly bound up in chemical compounds, notably water and hydrocarbons.  Extracting hydrogen from these compounds takes lots of energy.  To date, most hydrogen is produced from fossil fuel sources, resulting in carbon dioxide emissions.  So-called green hydrogen is made by splitting up water into its component elements.

Getting hydrogen from water generally uses electrolysis, which requires lots of electrical power.  That is why it isn’t the standard way to produce hydrogen; it costs too much to pay for all that power.

MIT scientists have been developing a process to make solar thermochemical hydrogen, or STCH.  STCH uses the sun’s heat to split apart water and no other energy source.  An existing source of solar heat drives a thermochemical reaction in which a heated metal surface grabs oxygen from steam and leaves hydrogen behind.  MIT did not invent the concept; their efforts are to make it practical.

Previous STCH designs were only capable of using 7% of incoming solar heat to make hydrogen.  The MIT process may be able to harness up to 40% of the sun’s heat and therefore generate far more hydrogen. 

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MIT design would harness 40 percent of the sun’s heat to produce clean hydrogen fuel

Photo, posted August 23, 2017, courtesy of Evan Lovely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fuel From Wind And Water | Earth Wise

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Hydrogen is the most common element in the universe and it can be used as a fuel to run cars, trains, and even airplanes.  Using it produces no harmful emissions.  However, to date, the way it is economically produced is not clean and green.  It is made from natural gas and leaves behind lots of carbon dioxide.

Around the world there are many projects working on so-called green hydrogen.  Producing hydrogen by splitting water into its component elements is called electrolysis and produces only oxygen as a waste product.  The problem with electrolysis is that it takes prodigious amounts of energy and therefore is very expensive.

A new project taking place in north Texas hopes to create the country’s first large-scale producer of green hydrogen.  The project is building a 900-megawatt wind farm along with a 500-megawatt solar farm.  The 1.4 gigawatts of total production capacity is more energy than the city of Austin consumes.  That energy will be used to produce 200,000 kilograms of hydrogen a day.

This project is among the largest proposed green hydrogen projects in the U.S.   There are green hydrogen proposals in Europe, Australia, Africa, and the Middle East that range from 10 GW to 67 GW. 

The Texas project, being developed in partnership by Air Products and AES, has been enabled by government support from the Inflation Reduction Act.    

There are a few thousand hydrogen-powered cars, boats, and trains but without substantial, cost-effective hydrogen infrastructure, the market is very limited.   Subsidizing the development of the necessary infrastructure is essential if there is any real chance to create the long-imagined hydrogen economy.

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Texas Project Will Use Wind to Make Fuel Out of Water

Photo, posted June 5, 2005, courtesy of City Transport Info via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Decarbonizing The Most Polluting Heavy Industries | Earth Wise

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The production of steel, cement, and ammonia accounts for about 20% of the carbon dioxide humans pour into the atmosphere.  Modern cities are largely constructed from concrete and steel and most of our food is grown using fertilizer made from ammonia. 

The most widely discussed solutions to decarbonizing these industries are green hydrogen and carbon capture and storage or CCS.

Steel manufacture is responsible for 11% of society’s emissions.  Most production starts by burning coal in a blast furnace. Using CCS could reduce emissions from burning the coal.  But the blast furnace could be eliminated entirely by the use of electrolysis to produce the pure iron needed to make steel.  This would be extremely energy-intensive but using a low-carbon source like green hydrogen could greatly reduce the emissions from making steel.

Ammonia is made by producing hydrogen from natural gas and then combining it with atmospheric nitrogen.  Both the hydrogen production and ammonia synthesis are energy intensive.  Using green hydrogen would eliminate emissions from the hydrogen production itself and new research on catalysts aims at lower-temperature, less-energy intensive ammonia synthesis.

Decarbonizing cement manufacturing is perhaps the toughest challenge.  Cement is made in a high-temperature kiln, typically heated by burning fossil fuels.  The process converts calcium carbonate and clay into a hard solid called clinker.  The main byproduct of that is even more carbon dioxide.  Burning green hydrogen and capturing carbon emission are about the best hope for reducing cement manufacturing emissions.

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Can the World’s Most Polluting Heavy Industries Decarbonize?

Photo, posted June 30, 2009, courtesy of Portland Bolt via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

New York And Green Hydrogen | Earth Wise

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In July, outgoing New York Governor Andrew Cuomo announced plans for the state to explore the potential role of green hydrogen as part of New York’s decarbonization strategy.

Green hydrogen is hydrogen produced using renewable energy, such as wind, solar, and hydro power.  While hydrogen itself is a carbon-free fuel, most of the hydrogen produced today is made with a process called natural gas reforming which has byproducts of carbon monoxide and carbon dioxide.  As a result, the environmental benefits of using hydrogen are largely lost.  Hydrogen is the most plentiful element in the universe but extracting it for use as a fuel is not easy.

Green hydrogen is obtained by splitting water molecules into their constituent hydrogen and oxygen parts.  In principle, oxygen is the only byproduct of the process.  The main drawback of electrolysis, as this process is called, is that it is energy intensive as well as being expensive.  But if that energy comes from renewable sources, then it is a clean process.

New York’s announcement is that the state will collaborate with the National Renewable Energy Laboratory and join two hydrogen-focused organizations to inform state decision-making, as well as make $12.5 million in funding available for long duration energy storage techniques and demonstration projects that may include green hydrogen.

Green hydrogen has the potential to decarbonize many of the more challenging sectors of the economy.  Hydrogen is a storable, transportable fuel that can replace fossil fuels in many applications.  Many experts believe that the so-called hydrogen economy could be the future of the world’s energy systems.  For that to happen, green hydrogen will need to be plentiful, sustainable, and inexpensive.

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New York announces initiatives to explore green hydrogen for decarbonization

Photo, posted October 26, 2019, courtesy of Pierre Blache via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Scaling Up Green Hydrogen | Earth Wise

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The global hydrogen market generates about $150 billion dollars a year.  The bulk of the market consists of hydrogen used to produce ammonia, refine oil, and produce methanol.  Advocates for hydrogen foresee a $600 billion a year market based on power and industry uses, mobility and transport uses, chemical feedstocks, and construction.  But the problem with expanding the use of hydrogen is that the vast majority of hydrogen in use today is produced from fossil fuels such as natural gas and coal and producing it creates carbon dioxide emissions.

The great hope of the industry is “green hydrogen”- hydrogen produced either without using fossil fuels at all or by capturing and storing the emissions generated. The most likely approach is electrolysis – using electricity to produce hydrogen from water.

Billions of dollars are being invested by both governments and by large oil companies in a race to scale up electrolysis and make it economically attractive.  According to the Hydrogen Council industry lobby group, at least $300 billion is expected to be invested globally over the next decade aimed at developing the green hydrogen that could one day meet almost a fifth of global energy demand.

Many argue that producing green hydrogen with electrolysis is an extremely inefficient way to utilize renewable energy.  Critics of hydrogen-powered vehicles particularly make this argument.   But industrial applications of hydrogen that currently use large amounts of fossil fuels – such as steel manufacturing – may be places where green hydrogen would make a real dent in global emissions.

The race to clean up hydrogen is definitely on.

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The Race to Scale Up Green Hydrogen to Help Solve Some of the World’s Dirtiest Energy Problems

Photo, posted December 16, 2020, courtesy of Sharon Hahn Darlin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Generating Hydrogen From Poor-Quality Water | Earth Wise

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Hydrogen could be the basis of a complete energy system.  It could be stored and transported and could be used to power vehicles and to generate electricity in power plants.  Proponents of the so-called hydrogen economy contend that hydrogen is the best solution to the global energy challenge.  But among the challenges faced by a hydrogen economy is the development of an efficient and green method to produce hydrogen.

The primary carbon-free method of producing hydrogen is to break down water into its constituent elements – hydrogen and oxygen.  This can be done in a number of ways, notably by using electricity in a process called electrolysis.  A method that seems particularly attractive is to use sunlight as the energy source that breaks down the water molecule.

While there is an abundance of water on our planet, only some of it is suitable for people to drink and consume in other ways.    Much of the accessible water on earth is salty or polluted.  So, a technique to obtain hydrogen from water ideally should work with water that is otherwise of little use to people.

Researchers in Russia and the Czech Republic have recently developed a new material that efficiently generates hydrogen molecules by exposing water – even saltwater or polluted water – to sunlight. 

The new material is a three-layer structure composed of a thin film of gold, an ultra-thin layer of platinum, and a metal-organic framework or MOF of chromium compounds and organic molecules.  The MOF layer acts as a filter that gets rid of impurities.

Experiments have demonstrated that 100 square centimeters of the material can generate half a liter of hydrogen in an hour.  The researchers continue to improve the material and increase its efficiency over a broad range of the solar spectrum.

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New Material Can Generate Hydrogen from Salt and Polluted Water

Photo courtesy of Tomsk Polytechnic University.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Way to Make Hydrogen

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Many people consider hydrogen to be the fuel of the future, both for powering vehicles and for storing energy generated by renewable sources.   Hydrogen itself is a clean and green fuel.  Generating energy from it using fuel cells results in only water as a byproduct.

The biggest problem with hydrogen is that the most economical way to produce it and therefore the way most hydrogen is produced today, is by reforming natural gas, which is a process that generates carbon emissions.

The desirable way to make hydrogen is to produce it by breaking apart water into its hydrogen and oxygen components, a process known as electrolysis.   There are many ways to do it, but none of them to date measures up in terms of efficiency, cost, and longevity.

Researchers at the University of Toronto have recently developed a new catalyst that uses abundant, low-cost elements to split water molecules into hydrogen and oxygen.  The catalyst is made from copper, nickel, and chromium, all of which are more abundant and less costly than platinum, which is the usual electrolysis catalyst.

The new catalyst performs well under pH-neutral conditions, which means it could even work on seawater without incurring the expense of desalination.  The Toronto researchers also believe their catalyst could be used as part of a process to make hydrocarbon fuels from hydrogen and CO22.  Their group is among the five finalists in the Carbon XPrize competition, which has a grand prize of $7.5 million for finding a way to convert waste CO2 into fuel.

Finding a low-cost, energy-efficient, and reliable way to make hydrogen out of water will be a big deal if it can be done on an industrial scale.

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U of T researchers discover low-cost way to produce hydrogen from water

Photo, posted July 23, 2015, courtesy of Magnus Johansson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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