mechanical

AI and greener cement

July 28, 2025 By EarthWise Leave a Comment

Cement pretty much holds the modern world together. The amount of cement required to create our infrastructure is almost incomprehensible. By weight, humanity consumes more cement than food, about 3 pounds per person per day. The cement industry produces around eight percent of global CO₂ emissions, which is more than the aviation industry. So, if the amount of emissions produced making concrete could be reduced by even a few percent, it would make a significant impact.

Cement plants utilize rotary kilns heated to 2,500 degrees Fahrenheit to burn ground limestone down to a substance called clinker. That energy-intensive combustion process emits large amounts of carbon dioxide. However, the combustion process accounts for much less than half of the emissions associated with making concrete. The majority comes from the raw materials needed to produce clinker.

One strategy to reduce concrete emissions is to modify the cement recipe itself, replacing some of the clinker with alternative materials. Some producers already make use of materials like slag from iron production and fly ash from coal-fired power plants.

A team of researchers at the Paul Scherrer Institute in Switzerland is making use of machine learning to simulate and optimize cement formulations that would emit significantly less CO₂ while maintaining the same high level of mechanical performance. This AI-based approach eliminates time-consuming experiments and conventional complex simulations.

The Scherrer Institute seeks to discover new materials and the effort has already yielded some promising candidates. The next steps will be testing some of these recipes in the laboratory.

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AI paves the way towards green cement

Photo, posted July 3, 2007, courtesy of Tim Shortt via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geological thermal energy storage

August 7, 2024 By EarthWise Leave a Comment

The electricity grid is increasingly using solar and wind power. Depending on those two sources requires the ability to store energy to have on hand when the sun isn’t shining and the wind isn’t blowing. Energy needs to be stored away to be used hours, days, or even weeks after it is produced.

Energy storage is booming. California has increased its energy storage capacity tenfold in recent times. One day in April, storage batteries were the largest source of electricity in the state for a period of two hours. But batteries are not the only way to store energy. There are chemical, electrochemical, mechanical, and thermal methods that each has potential advantages and unique features.

A project in Kern County, California, is making use of an abandoned oil field to create a long-term energy storage installation. The plan is to retrofit depleted oil wells to store concentrated solar energy in superheated groundwater for long periods of time. The stored heat can then be used to drive turbines when electricity is needed.

Some 1,200 feet below the surface of the oil field are pockets of permeable sandstone that have been emptied of the oil they previously contained. An array of parabolic mirrors will gather solar energy that will heat silicon oil in an underground loop to 700 degrees Fahrenheit. The oil pipeline will heat up groundwater down below. When electricity is needed, the heated groundwater will be brought to the surface to operate turbines.

There is no new technology involved. The individual aspects have never all been combined before, but the likelihood of success is high. There are lots of depleted oil fields that could be used this way in the future.

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Can a California Oilfield Be Retrofitted to Store Solar Energy?

Photo, posted July 18, 2017, courtesy of John Ciccarelli / BLM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biodegradable microplastics

April 10, 2024 By EarthWise Leave a Comment

Ordinary plastics are not biodegradable, but they are also not indestructible. Plastics in the environment can break down into tiny fragments – microplastics – and those, unfortunately, are nearly indestructible. Microplastics have been documented in the oceans and in soil virtually everywhere on Earth including remote frozen wastelands and on top of high mountains. More recently, they have been found in our own arteries, lungs, and even in placentas. Microplastic pollution is a very serious problem.

There is considerable ongoing effort to develop biodegradable plastics from non-petroleum sources. There has been progress but it has not necessarily been aimed at creating bioplastics that do not create microplastic when they break down.

Researchers at the University of California San Diego have developed algae-based polymers that they have shown to degrade when composted. Recently, in work published in the journal Nature Scientific Reports, they have shown that even fine microparticles of their bioplastic are digested by microbes when placed in a compost. What remains are the starting plant materials from which the plastic was made. Products made from this sort of plastic would not only be sustainable beyond their useful lifetime but would also not represent a potential danger to human life.

Creating this eco-friendly alternative to petroleum-based plastic is only the first step toward creating a viable replacement for existing plastics. It is necessary to be able to use the new material on existing manufacturing equipment and for it to have the same mechanical and thermal properties as the materials it is replacing. But the researchers are optimistic that this could be a potential solution to an increasingly serious problem.

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Say Hello to Biodegradable Microplastics

Photo, posted January 17, 2018, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Grid-Scale Gravity Energy Storage | Earth Wise

September 19, 2023 By EarthWise Leave a Comment

As wind and solar energy play a growing part in our energy system, the need for grid-scale energy storage is growing as well. An historic form of energy storage and still the largest in installed capacity is pumped hydro storage, which makes use of the potential energy contained in having water sitting at a higher elevation where it can be released downward to operate turbine generators. This is an effective system but is limited to places where geography cooperates.

For the past five years, a company called Energy Vault has been developing a system that uses the same principle to generate electricity but instead of pumping water to a higher elevation, it uses mechanical devices to lift heavy objects such as concrete blocks to an appropriate height. Lowering the blocks back to the ground drives generators.

To date, Energy Vault has only built demonstration systems with a fraction of the storage capacity needed for grid-scale operation. Their EV1 Tower in Switzerland was successfully grid interconnected in 2020 and demonstrated round-trip efficiency (the fraction of the energy stored that was produced by the generators) above 75%. Their improved EVx system is expected to do better than 80%.

This year the company, along with partners Atlas Renewable and China TIanying, is now in the first phases of commissioning a grid-scale system located outside of Shanghai, China. The 25-MW system is built adjacent to a wind farm and a national grid interconnection site

This is the first grid-scale gravity energy storage system and is expected to be fully online in the fourth quarter of this year. A second, similar system is now under contract to be built elsewhere in China.

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First grid-scale gravity energy storage system undergoes commencement in China

Photo courtesy of Energy Vault.

Earth Wise is a production of WAMC Northeast Public Radio

Cutting The Cost Of Energy Storage | Earth Wise

September 9, 2021 By EarthWise Leave a Comment

The cost of both solar and wind power continues to drop making the two renewable energy sources the cheapest way to make electricity in more and more places. Given the virtually inexhaustible supply of both wind and sun power, these clean electricity sources can in principle meet all our energy needs. The hang up is that both of them are intermittent sources – the wind doesn’t blow all the time and the sun doesn’t shine all the time.

The solution to the intermittency problem is energy storage. If energy produced by wind and sun can be stored so it can be made available for use at any time, then the goal of having 100% clean energy can be realized.

Energy storage technology has continued to improve over time and to get cheaper. The Department of Energy recently announced a new initiative aimed at accelerating both of these trends.

The new program – called Long Duration Storage Shot – has the goal of reducing the cost of grid-scale, long-duration energy storage by 90% within this decade.

Long-duration energy storage is defined as systems that can store energy for more than ten hours at a time. Such systems can support a low-cost, reliable, carbon-free electric grid that can supply power even when energy generation is unavailable or lower than demand. With long-duration storage, solar-generated power can be used at night.

The program will consider multiple types of storage technologies – electrochemical (that is: batteries), mechanical, thermal, chemical carriers, and various combinations thereof. Any technology that has the potential to meet the necessary duration and cost targets for long-term grid storage are fair game for the program.

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DOE announces goal to cut costs of long-duration energy storage by 90%

Photo, posted October 16, 2017, courtesy of UC Davis College of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.