applications

Solar thermochemical hydrogen

November 23, 2023 By EarthWise Leave a Comment

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

Fossil-free fertilizer

November 9, 2023 By EarthWise Leave a Comment

Ammonia is a major industrial commodity. About 70% of it is used to make fertilizer, with the rest for a wide range of industrial applications. Ammonia is the starting point for all mineral nitrogen fertilizers.

Typically, ammonia is a byproduct of isolating hydrogen from natural gas, which releases large amounts of carbon dioxide. On a global scale, the climate impact of ammonia production is comparable to that of air travel. The world needs more ammonia but really cannot afford the emissions that come with its production.

There are also political implications of ammonia production. Because it relies so heavily on natural gas, ammonia supply is vulnerable to disruptions from events like the Russian invasion of Ukraine. Sanctions imposed after the invasion have hindered fertilizer exports, driving up costs, especially in places like Africa.

A small fertilizer plant near Nairobi, Kenya will be the first farm in the world to produce its own nitrogen fertilizer on site that is free of fossil fuels. The plant is being built by an American startup company Talus Renewables and will use solar power to strip hydrogen from water. The hydrogen will then bond with nitrogen from the air to form liquid ammonia. The plant will produce one ton of ammonia each day.

The typical bag of fertilizer in sub-Saharan Africa travels 6,000 miles to get there, which of course only adds to the environmental burden of using it as well as its cost. By building a small green ammonia plant like the one coming online in Kenya, it is possible to locally produce a critical raw material in a carbon-free manner.

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Farm in Kenya First to Produce Fossil-Free Fertilizer On Site

Photo courtesy of Talus Renewables via LinkedIn.

Earth Wise is a production of WAMC Northeast Public Radio

Distributed Wind Energy | Earth Wise

March 17, 2023 By EarthWise 1 Comment

When we think about wind power, we are usually talking about increasingly giant windfarms – either on land or offshore – that produce power on a utility scale. But there is also distributed wind energy, which refers to wind technologies in locations that directly support individuals, communities, and businesses.

Distributed wind can be so-called behind-the-meter applications that directly offset retail electricity usage much as rooftop solar installations do. It can also be front-of-the-meter applications where the wind turbines are connected to the electricity distribution system and supplies energy on a community scale. Distributed wind installations can range from a several-hundred-watt little turbine that powers telecommunications equipment to a 10-megawatt community-scale energy facility. As of 2020, there were nearly 90,000 distributed wind turbines in the U.S. with a total capacity of about 1 GW.

A study by the National Renewable Energy Laboratory has estimated the potential for distributed wind energy in the U.S. According to the new analysis, the country has the ability to profitably provide nearly 1,400 GW of distributed wind energy capacity.

Entire regions of the country have abundant potential. The regions with the best economic prospects have a combination of high-quality wind, relatively high electricity rates, and good siting availability. Overall, the Midwest and Heartland regions had the highest potential especially within agricultural land.

Realizing this outcome for distributed wind will require improved financing and performance to lower costs, relaxation of siting requirement to open up more land for wind development, and continued investment tax credits and the use of net metering.

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U.S. has potential for 1,400 GW distributed wind energy, NREL finds

Photo, posted January 3, 2009, courtesy of skyseeker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Windows To Cool Buildings | Earth Wise

December 15, 2022 By EarthWise Leave a Comment

About 15% of global energy consumption is for cooling buildings. Because of this, there is an ever- growing need for technologies that can more efficiently cool buildings. Researchers at Notre Dame University have used advanced computing technology and artificial intelligence to design a transparent window coating that is able to lower the temperature inside buildings without using any energy.

The idea is to create a coating that blocks the sun’s ultraviolet and near-infrared light, which are parts of the solar spectrum that otherwise pass through glass and help to heat an enclosed room. Cooling needs can be reduced further if the coating can radiate heat from the surface of the window so it can pass through the atmosphere into space. Designing a coating that does both of those things simultaneously while transmitting visible light is difficult. Coatings should not interfere with the view out the window.

The Notre Dame researchers used advanced computer modeling to create a so-called transparent radiative cooler that meets these goals. The coating consists of alternating layers of common materials like silicon dioxide, silicon nitride, and aluminum oxide or titanium dioxide on top of a glass base and topped with a film of polydimethylsiloxane. The computing method was able to optimize this structure far faster and better than conventional design techniques.

The researchers say that in hot, dry cities, the coating could potentially reduce cooling energy consumption by 31% compared with conventional windows. The same materials could be used in other applications, such as car and truck windows. In addition, the quantum computing-enabled optimization method used for this work could be used to design other composite materials.

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Clear window coating could cool buildings without using energy

Photo, posted September 6, 2015, courtesy of Robert Otmn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Artificial Aquatic Polyps | Earth Wise

September 16, 2020 By EarthWise Leave a Comment

Corals are often mistaken for rocks because of their hardened surfaces. And, since they attach or “take root” to the sea floor, they are often mistaken for plants. But unlike rocks, corals are alive. And unlike plants, corals do not make their own food. Corals are actually animals.

Most of these structures that we call “coral” are made up of hundreds to thousands of tiny coral creatures called polyps. A coral polyp, which is often no thicker than a nickel, has a saclike body and mouth that is encircled by stinging tentacles. Polyps are responsible for a host of ecosystem services, including nourishing corals, and aiding coral survival by generating self-made currents through the motion of their soft bodies.

Inspired by these marine organisms, researchers from the University of Warwick in the UK and Eindhoven University of Technology in the Netherlands have collaborated to develop an artificial aquatic polyp capable of removing contaminants from water. The 1 square centimeter wireless robot polyp can attract, grasp, and release objects, moving under the influence of a magnetic field and whose “tentacles” are triggered by light.

The next step for the researchers is to see if the technology can be successfully scaled up from laboratory to pilot scale. In order for that to happen, the team has to design an array of artificial polyps capable of working harmoniously together.

Corals are an incredibly important part of ocean ecosystems. And while it remains to be seen how much value artificial polyps can achieve in future applications, it serves as another example of scientists emulating nature to create more sustainable designs.

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Aquatic robots can remove contaminant particles from water

An artificial aquatic polyp that wirelessly attracts, grasps, and releases objects

Photo, posted April 14, 2011, courtesy of Derek Keats via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Nanotech Water Purification | Earth Wise

July 14, 2020 By EarthWise Leave a Comment

We have occasionally talked about metal-organic frameworks, which are organic-inorganic hybrid crystalline structures that have a microscopic cage-like structure. MOFs have been under development for a diverse set of applications including gas storage and separation, liquid purification, energy storage, catalysis, and sensing.

For the first time, an international research team, led by researchers from Monash University in Australia, has created an ultrathin porous membrane based on MOF technology that can completely separate potentially harmful ions, such as lead and mercury, from water.

This innovation could enhance water desalination and transform even the dirtiest water into something potable for millions of people around the world. The new membrane performed steadily in tests for more than 750 hours using only limited energy.

The technology uses water-stable monolayer aluminum-based MOFs just a millionth of a millimeter in thickness. These are essentially two-dimensional structures. The ultrathin membrane is permeable to water – it achieves maximum porosity – but rejects nearly 100 percent of ions. It has been a daunting challenge to fabricate ultra-thin MOFs for water-based processing. Most previous membranes were too thick and unstable in water.

Most existing ion separation membrane technologies are based on polymers and have the limitation that they have limited selectivity. They don’t reject all unwanted ions.

The new membrane technology has great potential based on its precise and fast ion separation and could be ideal for a variety of filtration applications such as gas separation and separation of organic solvents such as paint. Such membranes might also be used to remove harmful carcinogens from the atmosphere.

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Ultrathin nanosheets separate ions from water

Photo courtesy of Monash University.

Earth Wise is a production of WAMC Northeast Public Radio.

A Squid Skin Blanket

June 25, 2019 By EarthWise Leave a Comment

Ultra-lightweight space blankets have been around for a long time. Marathon runners wrap themselves in them to avoid losing body heat after a race. They are very effective, but the amount of heat that they trap is fixed. There is no way to regulate how much heat is trapped or released using a space blanket.

Researchers at the University of California, Irvine have developed a next-generation, adaptive space blanket that allows users to control their temperature. The inspiration for the design was the skins of various species of squids, octopi and cuttlefish. The ability of these aquatic creatures to camouflage themselves by rapidly changing color is due, in part, to skin cells called chromatophores that can instantly change from tiny points to flattened disks.

The Irvine researchers have developed a material that contains a layer of tiny metal islands that border each other. In the relaxed state, the islands are bunched together, and the material reflects and traps heat, much like a conventional Mylar space blanket. But when the material is stretched, the islands spread apart, which allows infrared radiation to go through and heat to escape.

The researchers envision many other applications for the novel material, including adaptable insulation for buildings and tents that can be adapted to different weather conditions. There is even the possibility of clothing that can be adjusted to suit the comfort of each person.

The new material is lightweight, easy and inexpensive to manufacture, and is durable. It can be stretched and returned to its original state thousands of times. Some day we might all be wrapping ourselves in imitation squid skins.

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Squid skin inspires creation of next-generation space blanket

Photo, posted May 29, 2005, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.