on demand

Soda can hydrogen

August 15, 2025 By EarthWise Leave a Comment

Hydrogen is an ideal climate-friendly fuel because it doesn’t release carbon dioxide when it is used. But most hydrogen is produced in ways that result in significant carbon emissions. Thus, the search for green hydrogen goes on.

Last year, engineers at MIT developed a new process for making hydrogen that significantly reduces the carbon footprint of its production. The recipe uses seawater and recycled soda cans.

Pure aluminum reacts with water, breaking up the water molecules to produce aluminum oxide and pure hydrogen. But when aluminum is exposed to oxygen, it forms a shield-like layer that prevents the reaction.

The MIT researchers found that the shield can be removed by treating aluminum with a small amount of gallium-indium alloy. Mixing the pure aluminum with seawater not only produces hydrogen, but the salt in the seawater precipitates out the gallium-indium, making it available for reuse.

The research team carried out a “cradle-to-grave” life cycle assessment of the process, taking into account every step in using the hydrogen-production process at an industrial scale. They found that using recycled aluminum – chopped-up soda cans – is environmentally and economically superior to using “primary” aluminum, mined from the earth. The cans would be shredded into pellet and treated with the gallium-indium alloy. The pellets would be processed near a source of seawater where they would be combined to generate hydrogen on demand.

According to their analysis, the hydrogen produced would be at least competitive economically and environmentally with other potential methods of producing green hydrogen.

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Study shows making hydrogen with soda cans and seawater is scalable and sustainable

Photo, posted July 29, 2020, courtesy of Bruce Dupree via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water from thin air

September 6, 2024 By EarthWise Leave a Comment

The Earth’s atmosphere contains enormous amounts of water. Being able to efficiently and economically extract some of it to provide drinking water would be extremely beneficial to the billions of people across the globe who face chronic water shortages.

There are existing technologies for atmospheric water harvesting – or AWH. But there are downsides associated with size, cost, and efficiency. A new device developed by mechanical engineering researchers at the University of Utah has the potential to provide a new drinking water source in arid places.

The device is a compact, rapid-cycling, fuel-fired AWH device. It relies on adsorbent materials that draw water molecules out of non-humid air and then applies heat to release those molecules into liquid form.

Hygroscopic materials are those that have an affinity for water and soak it up at every opportunity. Such materials are used, for example, in disposable diapers. The Utah device makes use of metal organic frameworks, which have enormous amounts of surface area on the molecular scale.

The initial work on the Utah device targeted a small compact water generation unit for soldiers in the field. Instead of lugging around a large canteen filled with water, the small unit can produce water on demand. The prototype was able to produce 5 liters of water per day per kilogram of adsorbent material. Within three days in the field, the system outperforms packing water. The heat required to precipitate the liquid water was provided by a standard-issue Army camping stove.

Non-military needs are the ultimate application for the device. The researchers have applied for a patent for what they hope will be a potential solution to a persistent global problem.

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Producing water out of thin air

Photo, posted August 9, 2012, courtesy of Enid Martindale via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing Sunshine To Make Electricity On Demand | Earth Wise

June 1, 2022 By EarthWise Leave a Comment

Researchers at Chalmers University in Sweden have developed an entirely new way of capturing and storing energy from sunlight. The system is called the Molecular Thermal Energy Storage System or MOST. It is based on a specially designed molecule that changes shape when it is exposed to sunshine.

The molecule is composed of carbon, hydrogen, and nitrogen. When sunlight hits it, it changes into an energy-rich isomer – a molecule made up of the same atoms but arranged together in a different way. That isomer is stable and can be stored for many years. When a specially designed catalyst is applied, the stored energy is released in the form of heat and the molecule returns to its original form and can be reused.

The Chalmers researchers sent some of the energy-laden isomer to researchers in China who used it to operate a micron-thin thermoelectric generator, which used the heat released by the isomer material to generate electricity. The generator is an ultra-thin chip that could be integrated into electronics such as headphones, smart watches, and telephones. It is currently only at the proof-of-concept stage, but the results are quite promising. The integration with the MOST technology provides a way that solar energy can generate electricity regardless of weather, time of day, season, or geographical location. The results of the study were recently published in the journal Cell Reports Physical Science.

In effect, for this demonstration, Swedish sunshine was sent to the other side of the world and converted into electricity in China. The ultimate goal of this research is to create self-charging electronics that uses stored solar energy on demand.

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Converting solar energy to electricity on demand

Photo, posted March 11, 2013, courtesy of Steve Slater via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Possible Storage Breakthrough: Solar Energy | Earth Wise

January 10, 2020 By EarthWise 2 Comments

Solar energy is a nearly unlimited resource, but it is only available to us when the sun is shining. For solar power to provide for the majority of our energy needs, there needs to be a way to capture the energy from the sun, store it, and release it when we need it. There are many approaches to storing solar energy, but so far none have provided an ideal solution.

Scientists at the Chalmers Institute of Technology in Sweden have developed a way to harness solar energy and keep it in reserve so it can be released on demand in the form of heat—even decades after it was captured. Their solution combines several innovations, including an energy-trapping molecule, a storage system, and an energy-storing laminate for windows and textiles.

The energy-trapping molecule is made up of carbon, hydrogen, and nitrogen. When hit by sunlight, the molecule captures the sun’s energy and holds on to it until it is released as heat by a catalyst. The specialized storage unit is claimed to be able to store energy for decades. The transparent coating that the team developed also collects solar energy and releases heat. Using it would reduce the amount of electricity required for heating buildings.

So far, the team has concentrated on producing heat from stored solar energy. It is unclear whether the technology can be adapted to produce electricity, which would be even more valuable. In any event, the team does not yet have precise cost estimates for its technology, but there are no rare or expensive elements required, so the economics seem promising. There is much more work to be done, but this could be a very important technology for the world’s energy systems.

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An Energy Breakthrough Could Store Solar Power for Decades

Photo courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.