Soil Stabilization and Solidification, and the Potential to Incorporate Recycled Glass and Construction Waste into a Geopolymer-Based Soil Solidifier

     Soil stabilization can have a couple of slightly different definitions and goals. It is a standard procedure in geotechnical engineering to determine the stability of the soil before construction on a site. Soil stabilization may have to do with erosion prevention since erosion removes soil. In geotechnical engineering, soil stresses that influence how loads are transferred, are determined.  

     The Civil Engineering Portal has a good definition of soil stabilization:

“Soil stabilization is adding and mixing other materials into the soil to change its properties. Soil stabilization is a way to improve the soil’s shear strength parameters, which increases the soil’s ability to support the weight. It is usually needed when the soil under a building’s foundation is not strong enough to hold up the structure. Soil stabilization is a way to stop structures from sinking into the ground. It does this by making the soil less porous and easy to pack down. It also makes the soil more resistant to shear.”

     AMIX Systems has a good explanation of soil solidification:

“Soil solidification represents a crucial ground improvement method used in mining, tunneling, and construction projects to enhance the stability and load-bearing capacity of weak soils. This technique transforms problematic soil into a stronger, more stable material through the addition of binding agents that chemically react with soil particles. As projects increasingly encounter challenging ground conditions, the demand for effective soil stabilization methods continues to grow.”

AMIX provides grout mixing systems for soil solidification. According to building materials provider Holcim:

“…mixing cementitious materials into soil is one of the most efficient, cost-effective, and widely used methods for stabilizing and solidifying the ground in preparation for construction and redevelopment. Moreover, it is quick, extremely durable, and environmentally responsible.”

     While soil solidification is desirable for specific load-bearing sites on certain soils, it is undesirable for soil in general. It can also be used to contain and remediate soil contamination. Soil stabilization by adding carbon or clay also acts to reduce the mobility of soil contaminants. High-performance cements with longer setting and hardening time properties are utilized for soil cement stabilization and solidification. The slides below are from a 2024 Power Point presentation by Md Khairul Haque of Jatiya Kabi Kazi Nazrul Islam University.

 

Methods of Soil Stabilization and Solidification

     There are different methods of ‘ground improvement,’ with goals to increase soil strength, reduce settlement potential, control permeability, and mitigate liquefaction risks. Soil type, project requirements, site constraints, and economic considerations are factors in choosing the method. According to AMIX Systems:

“Common ground stabilization approaches include mechanical densification, preloading, reinforcement, and chemical treatment. Each method offers distinct advantages for specific soil conditions and project types. Mechanical densification, such as dynamic compaction, works well for granular soils but may be less effective for cohesive materials. Preloading requires significant time for consolidation to occur. Reinforcement techniques like stone columns provide excellent load distribution but may require specialized installation equipment.”

“Chemical treatment methods, including the process of strengthening weak ground through binding agents, have gained popularity due to their versatility and effectiveness across diverse soil types. These approaches modify soil properties through chemical reactions rather than purely mechanical means, often resulting in more permanent and predictable improvements.”

     Civil Engineering Portal lists ten types of soil stabilization: 1) mechanical; 2) chemical; 3) cement; 4) lime; 5) fly ash; 6) rice husk ash; 7) thermal; 8) bituminous; 9) electrical; and 10) geotextile and fabrics. Mechanical soil stabilization utilizes soil compaction with rollers, vibrators, and earth rammers. This reduces soil porosity. Chemical stabilization typically utilizes a salt, usually calcium chloride or sometimes sodium chloride. The result is lower vapor pressure, higher surface tension, slower evaporation, and less frost heaving. Cement stabilization involves mixing Portland cement and pulverized soil with water, followed by packing to strengthen the mixture. Lime stabilization is typically used to bind or improve the texture of clay soils, making them less attractive to water and less likely to swell. It works best in tropical regions as freezing causes it to degrade. Fly ash stabilization is popular due to the low cost of fly ash. It is usually incorporated with other cementitious binders. Rice husk ash is used similarly to fly ash. Both are highly reactive. Thermal stabilization lowers water content and makes clay soil more amenable to loads. Bituminous stabilization mostly utilizes asphalt and tar. It reduces moisture-holding capacity. Electrical stabilization improves the strength and drainage of clay soil. Geotextiles and porous fabrics made of polyethylene, polyester, nylon, and polyvinyl chloride are used to build roads without pavement on soft soils.

     Too much organic matter in the soil can result in acidity that is too high. Compaction increases soil strength. Sulfides and sulfates in the soil can complicate and slow stabilization. Moisture content and temperature affect reaction rates.

     AMIX Systems specializes in cementitious binding agents for soil stabilization and solidification:

“The primary mechanisms include hydration reactions, cation exchange, pozzolanic reactions, and physical bonding. Hydration reactions occur when cement-based binders react with water to form calcium silicate hydrate gels that crystallize and harden over time. Cation exchange happens when calcium ions from the binder replace weaker ions on clay particle surfaces, reducing plasticity and water sensitivity. Pozzolanic reactions involve the formation of additional cementitious compounds through interactions between the binder and silica or alumina in the soil.”

“The effectiveness of these stabilization processes depends on several factors: soil type and composition, moisture content, binder type and dosage, mixing efficiency, and curing conditions. Clay soils typically require different treatment approaches than sandy or silty materials due to their different surface chemistry and particle interaction behaviors. The moisture content must be carefully controlled to ensure optimal reactions without diluting the binding agents excessively.”

     Types of binding agents used according to AMIX Systems are shown below:

They also point out that Portland cement is costly, and that since fly ash and slag are waste products, they are cheap. Specialty grouts are very effective, but they require precise mixing and application techniques.

     The most common application techniques for soil stabilization include deep soil mixing, jet grouting, permeation grouting, and shallow stabilization.

“Deep soil mixing involves mechanical mixing of binding agents with in-situ soil using specialized equipment that can reach depths of 30 meters or more. This method creates columns or panels of treated soil that provide structural support and containment. The equipment typically includes a drilling rig with mixing tools that simultaneously inject and blend the binding agent with the soil. This technique works well for large-scale projects requiring significant depth of treatment.”

“Jet grouting uses high-pressure injection of grout to simultaneously erode and mix the soil with binding agents. This creates cylindrical columns of treated material that can form barriers, support structures, or underpinning elements. The process involves drilling to the desired depth, then injecting grout at pressures ranging from 300 to 600 bar, effectively cutting through and mixing with the surrounding soil. This method proves particularly useful in areas with limited access or when working around existing structures.”

     Some of the important equipment for soil solidification via grouts is listed below.

     According to Holcim, adding cementitious materials is the main method of soil stabilization:

“Soil cement stabilization is typically the method of choice when it comes to assuring the load-bearing capacity and quality of soil in preparation for road construction and civil engineering projects. This requires precise planning based on laboratory analysis to determine the optimal treatment approach. Solutions could involve the application of Portland limestone cement (PLC) or cement kiln dust (CKD) as a standalone treatment, or it may require the use of a custom blend of PLC and CKD or a blend of PLC and a supplementary cementitious material (SCM), such as slag or fly ash. It may also call for a ternary combination of various SCMs blended in proportions required to complete the job successfully.”

 

Soil Solidification Benefits

     The benefits of soil solidification for construction are numerous. By increasing bearing capacity, it enables unsuitable ground for building to be made suitable. It creates a more uniform foundation material and prevents differential settling. It is much cheaper and less disruptive than having to excavate and remove soil and then bring in expensive fill materials. By solidifying the existing soil, it is economically advantageous. It also enables the use of shallower foundations, which also lowers cost. Environmental advantages include minimum soil disturbance, less trucking of material into and off the site.

 

Soil Solidification Challenges

     The first challenge is to accurately characterize the soil. This is typically done by geotechnical engineers and geologists. Once the soil is adequately characterized, the binding agents and dosages can be determined. The geochemistry of the soil is also important. The presence of organic matter, sulfides and sulfates, extreme pH, and contaminants can affect binding reactions,  triggering the need for additives or alternative approaches. Quality control and monitoring of the soil at the site need to be ongoing. This includes periodic sampling, laboratory testing, field penetration tests, and other verification methods. Environmental challenges include dust management and runoff management. Documentation of the material used is required for regulatory purposes. Below are AMIX’s recommended strategies for overcoming these challenges.

 

The Future of Soil Solidification Technology

     AMIX Systems provides a good analysis of emerging technology in soil solidification, noting that binding agents, like specialty grouts, and grout mixing capabilities in different environments is a major focus:

Innovative binding agents represent one of the most active areas of development. Research into geopolymers, bio-based stabilizers, and nano-modified materials promises to deliver improved performance with reduced environmental impact. These next-generation materials may offer faster strength development, greater durability in aggressive environments, or specialized properties like self-healing capabilities.

“Advanced mixing and application technologies are also transforming the industry. Computer-controlled batching systems provide unprecedented precision in mixture proportioning, while automated quality control systems offer real-time monitoring of treatment effectiveness. Specialized equipment for challenging environments, such as underwater or contaminated sites, continues to expand the applicability of these techniques.”

“Sustainability considerations increasingly drive innovation in this field. The industry is moving toward lower-carbon binding agents, energy-efficient equipment, and processes that minimize waste generation. The incorporation of recycled materials and industrial byproducts as supplementary binding agents supports circular economy principles while often enhancing treatment performance.”

They recommend a process of four steps: 1) Geotechnical site investigation, soil boring, and laboratory testing to determine optimal approach, 2) Select the proper equipment and sizes for the job, 3) Quality control and monitoring programs including pre-construction testing, production monitoring, and post-treatment verification, and 4) partner with experienced equipment providers for both equipment and technical support.

 

Soil Nailing

     Another specialty method of soil stabilization is soil nailing. In the 2010s, a colleague of mine in the oil and gas industry was working for Geostabilization International (GSI) and gave a talk at a conference we both attended on soil nailing for stabilizing vulnerable slopes along oil & gas lease roads in hilly areas. GSI describes soil nailing as follows:

“An engineered method used to stabilize existing slopes or excavation utilizing “top down” construction sequencing. This passive reinforcement system remediates unstable natural slopes or construct new or existing over-steepened slopes using closely spaced steel inclusions. The practice involves drilling solid or hollow bars to depths specified by a geotechnical engineer. GeoStabilization’s innovative ™ Nail Launcher Soil utilizes compressed air to blast up to 20-foot-long nails into the slope at speeds reaching 250-mph.”

“Soil nails are reinforced bars installed in soil mass. Soil nails can be installed in a variety of methods including drilled, driven, or launched nails and can be installed in a wide range of soil conditions accommodating changes in ground conditions. Soil nails perform well under seismic loading due to coupling with the ground. Each installed nail is a soil probe which can aid in design refinement during construction. Soil nails are part of a soil-structure system, consisting of the following elements: earth materials, tendons, grout, facing, connections, and drainage.”

Self-drilling soil nails are used to stabilize active landslides or collapsing soil. Open-hole soil nails use the nail itself to drill the hole and grout as the drilling fluid. The result is an effective grout column where the grout mixes well with the surrounding material. Launched soil nails utilize highly compressed air to force the nails into place.  The nails are usually fully grouted and installed at a slight downward inclination, with regularly spaced points across the slope. Steel-reinforced rigid shotcrete or flexible wire mesh can add strength and erosion control. An advantage of soil nailing is its low cost compared to other soil stabilization methods.

 

New Research Incorporates Recycled Glass and Construction Waste into a Geopolymer-Based Soil Solidifier

     New research shows very good results incorporating recycled glass and siding waste into a geopolymer-based soil solidifying cementitious material. The use of waste materials for binding instead of expensive Portland cement makes the process cost-effective. Japanese scientists at the Shibaura Institute of Technology (SIT) utilized a high-performance geopolymer-based soil solidifier developed from Siding Cut Powder (SCP), a construction waste byproduct, and earth silica (ES), sourced from recycled glass. The result is a solidified soil with adequate strength for construction. Thermal treatment of SCP at 110 °C and 200 °C was a critical step. This increases reactivity. The researchers also demonstrated that incorporating calcium hydroxide effectively mitigated the potential for arsenic leaching from the glass by reacting it to form more stable calcium arsenate compounds.

     According to Wikipedia:

“A geopolymer is an inorganic, often ceramic-like material, that forms a stable, covalently bonded, non-crystalline to semi-crystalline network through the reaction of aluminosilicate materials with an alkaline or acidic solution. Many geopolymers may also be classified as alkali-activated cements or acid-activated binders. They are mainly produced by a chemical reaction between a chemically reactive aluminosilicate powder e.g. metakaolin or other clay-derived powders, natural pozzolan, or suitable glasses, and an aqueous solution (alkaline or acidic) that causes this powder to react and re-form into a solid monolith. The most common pathway to produce geopolymers is by the reaction of metakaolin with sodium silicate, which is an alkaline solution, but other processes are also possible.”

     The geopolymer has “proven durability under sulfate attack, chloride ingress, and freeze-thaw cycles.” Its main advantage is the replacement of Portland cement, resulting in significantly lower cost and significantly lower pollution and greenhouse gas emissions. It represents another sustainable construction method that will likely catch on. Key findings and future research directions of ES and SCP-based geopolymers, from the paper published in Cleaner Engineering and Technology, are shown below.

 

      

 

References:

 

Geopolymer technology turns recycled glass and construction waste into a durable and green construction material. Science X staff. TechXplore. May 29, 2025. Geopolymer technology turns recycled glass and construction waste into a durable and green construction material

Development of environmentally sustainable geopolymer-based soil solidifiers using waste siding and glass powders. Shinya Inazumi, Ryo Hashimoto, Yoji Hontani, Atsuya Yoshimoto, Ken-ichi Shishido, and Kuo Chieh Chao. Cleaner Engineering and Technology. Volume 26, May 2025, 100976. Development of environmentally sustainable geopolymer-based soil solidifiers using waste siding and glass powders - ScienceDirect

Revolutionary Soil Solidification for Stability. AMIX Systems. Revolutionary Soil Solidification for Stability - AMIX Systems

Soil Cement Stabilization and Solidification: Custom Solutions for High Performance and Sustainability. Holcim. Soil Cement Stabilization and Solidification | Holcim US

What is Soil Stabilization, and what are the Methods of Soil Stabilization? Civil Engineering Portal. What is Soil Stabilization, and what are the Methods of Soil Stabilization? - Civil Engineering Portal

Community Guide to Solidification and Stabilization. US EPA. April 2021. Community Guide to Solidification and Stabilization

Soil Sol-idification, Soil Acidi-fication, Soil Alkalizat-ion and Soil Pol-lution Presented By Md Khairul Haque. Jatiya Kabi Kazi Nazrul Islam University. March 2024. (PDF) Soil Sol-idification, Soil Acidi-fication, Soil Alkalizat-ion and Soil Pol-lution Presented By

What is Soil Nailing? Geostabilization International. Soil Nailing - Geostabilization International

Geopolymer. Wikipedia. Geopolymer - Wikipedia

Global Deforestation Surges in 2024 Due to Fires, According to World Resources Institute

     The World Resources Institute (WRI) reported in May 2025 that global deforestation rose in 2024, triggered mainly by fires. WRI runs Global Forest Watch, which tracks global deforestation.

“For the first time on our record, fires — not agriculture — were the leading cause of tropical primary forest loss, accounting for nearly 50% of all destruction. This marks a dramatic shift from recent years, when fires averaged just 20%. Meanwhile, tropical primary forest loss driven by other causes also jumped by 14%, the sharpest increase since 2016.” 

     WRI’s press release about the updated 2024 data included that the Glasgow Leaders Declaration in 2021, pledging to halt and reverse forest loss by 2030, is seriously behind its trajectory.

     Fires are both wildfires and fires set to prepare an area for agriculture: crops and/or grazing. Fires are also major sources of pollutants and greenhouse gas emissions. They also destroy habitat. They can also strain local water supplies. Droughts in Brazil led to an increase in fires there in 2024. Fires in tropical regions are predominantly caused by humans.  

     In 2024. Brazil, followed by neighboring Bolivia, led global forest loss by country. The DRC in Africa moved back to third place. Bolivia’s increase was led by a majority of fires set to clear land for soy, cattle, and sugarcane. A severe drought allowed the fires to spread into bigger fires that were harder to control. The problem in Bolivia was blamed on both too much land clearing and inadequate fire response.

     A nearly 50% increase in forest loss in Colombia was blamed less on fires and more on clearing land for illegal mining and coca leaf production, two undesirable trends. Thus, corruption and organized crime are driving some deforestation.

     The Congo Basin of Central Africa also had an increase in fires due to drought and hot weather. The region of the DRC suffers from land clearing for cooking wood/charcoal and agriculture. Armed conflict also increased forest loss.

     Southeast Asia showed some reductions in forest loss, so that is a positive trend.

“Indonesia reduced primary forest loss by 11%, reversing a steady rise between 2021 and 2023. Efforts under former President Joko Widodo to restore land and curb fires helped keep fire rates low, even amid widespread droughts. Similarly, Malaysia saw a 13% decline and fell out of the top 10 countries for tropical primary forest loss for the first time.”

     In non-tropical countries, wildfires in Canada and Russia helped to lead to a 5% increase in global forest loss. 2024 was the worst year on record for fire-driven forest loss, and this is concerning. Solutions are possible, as successful policies have shown.

“To meet the global goal of halting forest loss by 2030, the world must reduce deforestation by 20% every year, starting immediately. In contrast, 2024 marked an 80% increase in tropical primary forest loss. To combat this loss, the world needs action on multiple fronts: stronger fire prevention, deforestation-free supply chains for commodities, better enforcement of trade regulations and increased funding for forest protection — especially Indigenous-led initiatives.”

     WRI’s Global Forest Watch runs in conjunction with the University of Maryland. They have a great map and dashboard that can be accessed. It “captures changes at approximately 30 × 30-meter resolution across all global land areas, except Antarctica and other Arctic islands.”

   

References:

 

RELEASE: Global Forest Loss Shatters Records in 2024, Fueled by Massive Fires. World Resources Institute. May 20, 2025. RELEASE: Global Forest Loss Shatters Records in 2024, Fueled by Massive Fires | World Resources Institute

Global Deforestation Dashboard. Global Forest Watch. Global Deforestation Rates & Statistics by Country | GFW

Hybrid (HEV) vs. Plug-in Hybrid (PHEV) vs. Battery Electric (BEV): Cost, Incentives, and Emissions Comparisons

     Having owned two hybrids and one plug-in hybrid (PHEV) over the years, I have enjoyed the advantages in cost of ownership. These include superior gas mileage, fewer trips to the gas station (depending on fuel tank size), and, for plug-ins, the ability to charge up at home. I am currently driving a 2010 Honda Insight hybrid that gets 43MPG. It dropped over the last year from 46.5MPG, which made me think the 15-year-old battery was degrading, but I am guessing I just lost a cell, as the loss of mileage was steady over a few months, then just stopped. It has remained steady for more than a few months now.  I know I will have to replace the battery at some point and will likely do so as long as the mileage is not very high. Currently, it is about 119,000 miles.

     There are some disincentives to owning these vehicles as well. When I bought my recent hybrid and went to get it registered at the BMV, I was charged $100 due to being a hybrid. This is presumably to pay for those things that gasoline and diesel taxes pay for, like road repairs, etc. Many states have these charges that claw back a little of the loss in tax revenue.

     According to the Energy Information Administration, hybrids, PHEVs, and BEVs make up 22% of U.S. light-duty vehicle sales. Of those, hybrids make up 12%, PHEVs make up 2%, and EVs make up about 8%. They also note that battery EVs make up a large part of what is called the luxury market.

“Battery electric vehicle sales in particular are more common in the luxury vehicle market. U.S. luxury vehicles accounted for 14% of the total light-duty vehicle market in the first quarter of the year, the lowest share since mid-2020. Electric vehicles accounted for 23% of total luxury sales in the first quarter of 2025. Electric vehicles had accounted for more than one-third of luxury sales in 2023 and 2024 before Wards reclassified the Tesla Model 3 as non-luxury in late 2024.”

Battery EVs also cost up to 25% more. Of course, who can afford a new car these days?! I bought a new PHEV in 2019 for $30,000. Unfortunately, a year later, I hit a deer and totaled it. A few days later I got laid off. I don’t foresee ever buying a new vehicle again, probably only used ones for the rest of my days.

“Battery electric vehicles’ average transaction prices remain persistently higher than the overall market: the average transaction prices increased from $55,500 in December 2024 to $59,200 in March 2025, compared with the average price of all new vehicles, which decreased from $49,700 to $47,500. This 25% difference between battery electric vehicles and the industry average prices in March 2025 was the highest in any month since April 2023.”

 

HEVs, PHEVs, and BEVs: Emissions Differences Are Dependent on Several Factors

     Kumar Venkat, in an August 2023 article in Illuminem, explores and compares emissions. He first notes Toyota’s claim that the critical minerals used for one BEV can be used for six PHEVs or 90 hybrids. He notes that critical minerals may become constrained in the future and that their supply chains are often powered by fossil fuels. Add to that the fact that the grids BEVs and PHEVs plug into may be powered largely by fossil fuels. These differences in power sources for the minerals supply chain and tapped grids make determining emissions more variable and difficult. The use of life cycle assessments (LCAs) for determining emissions is how they are estimated. Venkat did LCA analysis based on the California grid and an average for Midwestern grids, which are shown in the graphs below. His conclusions are that right now in these places, PHEVs have lower emissions intensity than BEVs. In the future, when minerals supply chains are cleaner and grid energy is cleaner, that will likely change, but there are still some “ifs” in there. HEVs come in slightly higher than BEVs, but ICE vehicles are 30% higher than HEVs.

     The key points are that, right now, PHEVs and HEVs are very good for low emissions, at costs that are much lower than BEVs. They are also much more convenient because they don’t solely rely on charger availability. Things will change in the future as battery chemistries change, as EV ranges improve, and as chargers become more available. I would say that the hurried rollout of BEVs and chargers was premature. When I had a PHEV, I also installed a Level 2 charger at my house. I was able to dig the trench and bury the conduit myself in order to save a ton of money. The electrician ran the wire through and hooked everything up. It was great. In the future, I will look to buy affordable used HEVs or PHEVs.

     Venkat’s conclusion is that PHEVs are a logical intermediate technology:

“While the electrification of personal transport is necessary to get to net zero emissions by 2050, we could easily make the transition much harder by racing towards 100% electrification before we have sufficiently expanded, diversified, and cleaned up the mineral supply chains. A lifecycle perspective of transport solutions would suggest that electrification should be done in alignment with projected improvements in battery production as well as clean power generation. PHEVs are a logical intermediate technology in this transition that can deliver better climate benefits today while using critical resources more efficiently.”

    

 

References:

 

Hybrid vehicle sales continue to rise as electric and plug-in vehicle shares remain flat. U.S. Energy Information Administration. May 30, 2025. Hybrid vehicle sales continue to rise as electric and plug-in vehicle shares remain flat - U.S. Energy Information Administration (EIA)

Why plug-in hybrids (PEVs) are better for the climate than full Electric Vehicles (BEVs) today. Illuminem. Kumar Venkat. August 7, 2023. Why plug-in hybrids (PEVs) are better for the climate than full Electric Vehicles (BEVs) today | illuminem

 

Sub-Saharan Africa Needs Fossil Fuels to Process Its Critical Minerals – by Ryan Alimento and Seaver Wang. Breakthrough Institute. Summary and Review

     This article gives three case studies of sub-Saharan African critical minerals projects that would benefit immensely from fossil fuel availability to process those minerals locally rather than shipping them away for processing. The article cites a 2024 IMF report that 30% of the world’s undeveloped critical minerals are contained in sub-Saharan Africa (SSA). Mineral processing to any degree requires fossil fuels for thermal energy and industrial chemicals. It requires the development of domestic chemical and metallurgical industries. Such an effort would also require workforce training and collaboration with advanced economies. Each of the three cases is unique. This article focuses on an engineering-based analysis.

 

Case Study 1) Cobalt and Copper in the Democratic Republic of the Congo (DRC)

     The DRC is the world largest mined cobalt producer and the second-largest producer of both mined and refined copper, with 220 ktpy (thousand tons per year) of mined cobalt (75% of global supply), 3,300 ktpy of mined copper (15% of global supply), and 2,500 ktpy of copper metal (9% of global supply). Despite this vast mineral wealth, the DRC is among the poorest countries in the world and has been suffering from regional military conflict. DRC’s copper is already processed enough for export, but there are opportunities to develop further processing of cobalt into battery-grade cobalt sulfate, which is currently shipped out in the form of unprocessed cobalt ore. Below are the processing steps that could be added for cobalt: leaching, evaporation, and crystallization, and end products.

     Those cobalt processing steps require large thermal energy inputs. Those inputs, both electrical and non-electrical (direct thermal), are shown below.

     The non-electrical thermal energy needs require fossil fuels. However, the DRC does not use natural gas or coal. The DRC does produce about 25,000 Bbls of oil per day for export. That comes offshore from the far west sliver of the country that intersects the Atlantic Ocean. It would need port development and pipelines to bring oil to the cobalt region. They could import natural gas and pipeline it to co-locate it with cobalt processing facilities. Unfortunately, development finance institutions have declined to invest in fossil fuel projects due to climate concerns.

“A natural gas import terminal co-located with a cobalt sulfate plant could be an effective pilot investment in the DRC. Nearby gas power plants could also ensure that the cobalt sulfate plant and potential future port developments have stable electricity access. Regardless of the specific provisions, withholding fossil fuel investments in the DRC places upper limits on economic development that no regional trade agreement or creative financing method can remedy as effectively.”

 

Case Study 2) Aluminum and Alumina in Guinea

     The West African country of Guinea has the largest remaining reserves of bauxite aluminum ore in the world, nearly three times as the next country, Indonesia. The country has one alumina refinery, but it has operated inconsistently, and plans to open another much larger plant in 2027 with help from Chinese investors. They are also building a 250MW power plant, presumably natural gas, to power the refinery. As seen in the second figure below, electricity is the main energy input needed for the plant. It can support the new refinery, but any further projects would require more electricity and more fossil fuels. The country could utilize its abundant hydropower for electricity, but it would need to build out more hydroelectric plants and power transmission infrastructure. The smelters would also need coal and oil to make the anodes for the smelters.

     If Guinea could increase its aluminum refining capacity, it could also refine gallium. Gallium is present in bauxite ores. In Guinea, even though the percentage of gallium in the ore is low, it could become a major global source if developed. China currently produces 99% of the world’s gallium and has recently banned gallium exports to the U.S.

“Gallium or not, a productive and vertically-integrated aluminum supply chain in Guinea’s future is possible but is contingent on increased fossil fuel access. Future expansions to alumina refining need fossil fuels to supply process heat, and an aluminum smelter uses fossil fuels as chemical feedstocks for carbon anodes. Moreover, the enormous electricity demands of aluminum smelting requires considerable expansions to Guinea’s generation of reliable electricity. A smelter’s electricity could be supplied using local hydropower, but a realistic plan to grow Guinean industry around clean electricity starts with using a non-negligible amount of petrochemicals.”

 

Case Study 3) Graphite in Mozambique

     Mozambique was the world’s second-largest graphite producer in 2023, with only one mine, begun in 2017, by an Australian company. It produces minimally processed flake graphite concentrate that is sent to Louisiana for final processing to be used for anodes in American batteries. The power requirements for the next processing steps, micronization and spheroidization, are lower than those for processing other minerals.

     Unfortunately, like the DRC, Mozambique has been mired in regional conflicts, which closed the one mine in late 2024. It is expected to restart soon, but six months of production will be lost, and there is still uncertainty going forward.

 

Energy is Needed for Further Mineral Processing, and Fossil Fuels Are Needed for Process Heat

     The authors stress that intermediate and final downstream processing steps for minerals often require the most electricity, chemicals, and process heat. They also argue that “blanket moratoriums on fossil fuel infrastructure” are not necessary and only serve to hurt those countries. Globally, China dominates downstream minerals processing to a high degree. That domination discourages competition since they have established relationships with end-users. Chemicals would need to be imported as well. The DRC would have to import sulfur and sulfuric acid for cobalt processing, Guinea would have to import caustic soda and lime for bauxite processing, and Mozambique would have to import machinery from China to micronize and spheroidize graphite, since China does 99% of that globally. Training local laborers will also be a challenge to developing these industries.

“To be sure, African countries should endeavor to substitute fossil fuels with clean alternatives wherever possible. Already, the continent is poised to develop industries using far cleaner pathways than those taken by existing industry in developed countries today. But there are immutable technological and economic limitations on the extent to which petrochemical substitutions can occur, especially amidst the intense competition of commodity markets. Both electrical and thermal energy infrastructure are vital prerequisites for countries in sub-Saharan Africa to truly take advantage of their mineral resources. And failure to pragmatically acknowledge the need for fossil fuels for modern economic growth risks jeopardizing both African development and the clean energy transition at large.”

     The minerals are there to be produced, and the ability to process them should be developed and optimized as much as possible and practical, but it can’t happen without more electricity and more fossil fuels.

  

  

References:

 

Sub-Saharan Africa Needs Fossil Fuels to Process Its Critical Minerals. Ryan Alimento and Seaver Wang. Breakthrough Institute. June 4, 2025. Sub-Saharan Africa Needs Fossil Fuels to… | The Breakthrough Institute

Regional Economic Outlook.  Analytical Note. Sub-Saharan Africa. International Monetary Fund. Digging for Opportunity: Harnessing Sub-Saharan Africa’s Wealth in Critical Minerals. April 2024. MineralsNote.pdf

Chinese firm to build Guinea’s biggest alumina processing plant. Bloomberg News. January 2, 2025. Chinese firm to build Guinea’s biggest alumina processing plant - MINING.COM

 

Advanced Clean Energy Storage Delta Project in Utah Set to Burn Natural Gas and Hydrogen and Store Them in Salt Dome Caverns Below a Former Coal-Fired Plant Site

     Work is progressing on the Advanced Clean Energy Store Delta project near Delta, Utah, at the 4,614-acre site of the Intermountain Power Project. Delta is just south of Salt Lake City. The ACES Delta project involves retooling an old coal-fired power plant to burn a blend of natural gas and green hydrogen. The project will use Mitsubishi’s M501JAC turbines capable of burning 30% hydrogen blended with natural gas and up to 100% hydrogen by 2045, according to Power Magazine’s 2022 report about the project. Construction began in 2022. The project is a joint venture between Haddington Ventures, Mitsubishi Heavy Industries, and Chevron. Chevron bought out the company Magnum Development and its original share in the project in September 2023, to become the majority investor. The project secured a DOE loan guarantee of $504 million in June 2022. The project was first unveiled in May 2019 and was originally hoped to be online in 2025. According to Mitsubishi:

“The first project to combine utility and industrial-scale renewable hydrogen production, storage, and transmission, the Advanced Clean Energy Storage project will support the Intermountain Power Agency’s (IPA) IPP Renewed Project—an 840 MW hydrogen-capable gas turbine combined cycle power plant that will initially run on a blend of green hydrogen and natural gas starting in 2025 and incrementally expanding to 100% green hydrogen by 2045.”

     Work yet to be done includes drilling wells into two massive salt dome caverns, which together are capable of holding the equivalent of 4.5 million barrels of oil. The caverns will be filled with a 70%/30% natural gas and hydrogen blend. The coal-fired plant is beginning decommissioning this year and is expected to be fully decommissioned by 2027. Power transmission lines are being upgraded. Surplus renewable energy, or curtailed generation, from Utah and Southern California, is expected to be used to power the electrolyzers that will produce the green hydrogen. California has a large amount of solar overgeneration and sometimes has to give it away at a loss. Thus, that energy source is expected to be available at a low cost. The initial design calls for converting 220 MW of renewable energy into 100 metric tons of green hydrogen daily. Petar Willhite, project manager for the EPC contractor, The Industrial Company (TIC), notes that the project provides:

“…a significant opportunity for deploying seasonable renewable energy storage at a massive scale.”

     Greenhouse gas emissions are expected to decrease by 75% compared to the coal-fired plant.

     According to Good News Network:

“The final piece of work on the project is the modernization of the 2,400-MW transmission system linking the plant to Southern California. That will include building new DC converter stations at both ends of the line. It is due for completion in 2027.”

“Advancing the project to this point has required a lot of cooperation. IPP’s participant utilities range from among the largest in the country to some very small towns, all with very different needs.”

“We were able to come together for a project that works for everyone by relying on the goodwill and working relationships that have been developed over nearly 40 years of operating the original project,” Ward says. “This is truly a shining example of the benefits of regional energy cooperation.”

     The upgraded power connection and related equipment to Southern California solar generation sources allow the project to be powered by the significant amount of curtailed solar in the region. It also allows for the delivery of needed power on demand to the Southern California region when power demand rises in events like heat waves.

     Mitsubishi wrote a white paper in 2022 calling for more energy storage in the Western U.S. I could not find a map that shows a salt dome near the site, but I assume it is well-confirmed. The engineering company tasked with developing the salt dome caverns is very experienced in salt dome hydrocarbon and hydrogen storage. The location appears to be near the Bonneville Evaporite Basin, which is at and near the surface. In the subsurface, all I could find was a map showing bedded evaporites in the Sevier Desert region. The image below gives the depth (3400-4300ft) to the storage caverns.

   

 

References:

 

Hydrogen Gas Blend Will Reduce Power Plant’s Emissions by 75%–as it Helps Power 6 States. Andy Corbley. Good News Network. June 3, 2025. Hydrogen Gas Blend Will Reduce Power Plant's Emissions by 75%–as it Helps Power 6 States

Coal-Fired Power Plant Will Gain New Life with Green Hydrogen. James Leggate. ENR Mountain States & Southwest. April 26, 2025. Coal-Fired Power Plant Will Gain New Life with Green Hydrogen | Engineering News-Record

Chevron acquires majority stake in the advanced clean energy storage hydrogen project in delta, Utah. Chevron. Press Release. September 12, 2023. Chevron acquires majority stake in the Advanced Clean Energy Storage hydrogen project in Delta, Utah — Chevron

Why the Western U.S. Needs Energy Storage. Mitsubishi Power. March 2022. Mitsubishi-Power-White-Paper-Why-the-Western-U.S.-Needs-Energy-Storage.pdf

Bold Moves for a Brighter Tomorrow. ACES Delta. Advanced Clean Energy Storage Site | ACES Delta

ACES Delta's Giant Utah Salt Cavern Hydrogen Storage Project Gets $504M Conditional DOE Loan Guarantee. Sonal Patel. Power Magazine. April 28, 2022. ACES Delta's Giant Utah Salt Cavern Hydrogen Storage Project Gets $504M Conditional DOE Loan Guarantee

The Power of Collaboration. Mitsubishi Heavy Industries Group. Advanced Clean Energy Storage Project | Mitsubishi Power Americas, Inc.

Mapping mineralogy in evaporite basins through time using multispectral Landsat data: Examples from the Bonneville basin, Utah, USA. Mark H. Radwin and Brenda B. Bowen. August 2020. Earth Surf Process Landforms. 2021;1–17. Mapping mineralogy in evaporite basins through time using multispectral Landsat data: Examples from the Bonneville basin, Utah, USA

Baker Hughes’ Hummingbird Oil & Gas Well Cementing Unit: Oilfield Electrification Continues

     Oilfield electrification has been proceeding over the last decade and especially over the last five years. More operators than ever before are using electric pumps for frac jobs, electrified or hybrid drilling rigs, and electrical power management systems for optimizing power usage. I wrote about these in my 2022 book, Natural Gas and Decarbonization. Now, Baker Hughes is the first company to introduce an all-electric land cementing unit, which they call the Hummingbird.

     The Hummingbird unit runs on batteries or can be connected to the local grid. I assume that also means it can be powered by natural gas-powered generator sets, as is common in E-frac operations. It offers pump redundancy, quiet operation, emissions reduction, high reliability, and lower operational cost.

“The Hummingbird combines cement mixing and pumping in a single trailer-mounted unit designed for reliable operation in high-pressure applications. The unit is rated to approximately 1,050 hydraulic horsepower (782 kW) and is equipped with two high-pressure triplex pumps. While actual performance depends on fluid end plunger size selection, the unit is designed for reliable pumping performance at working pressures of up to 12,000 psi (82.7 MPa).”   

     In May 2025, World Oil interviewed Baker Hughes engineer Greg Dean about the new cementing unit. Dean noted that the prototype is finished, function-tested, and headed out into the field. Its first test in the field will be in the Middle East.

     Dean noted the reliability improvements of electric motors vs. diesel hydraulic motors, which can be hard to predict. Electric motors will have less downtime, maintenance requirements, and costs. Performance is expected to meet or exceed hydraulic units. Power usage is about 1 MW. The units run on 440 volts. The sound level is about the level of a lawnmower, versus hydraulic power, which can be as much as a helicopter running at full force. Workers in the field will like that, and it improves safety.

   Right now, with just a prototype, the costs are higher, but as more units are rolled out, the Hummingbird unit is expected to be cost-competitive with diesel-hydraulic units. Operational power costs will be lower. Dean expects field performance review and customer feedback in a matter of weeks. The cement pumps and mixing systems for the Hummingbird unit are the same as for the diesel units. Data can be generated and analyzed, including with AI, to optimize system performance.

  

 

References:

 

Baker Hughes engineer touts debut of new all-electric land cementing unit. World Oil. May 2025. Baker Hughes engineer touts debut of new all-electric land cementing unit  

Hummingbird all-electric land cementing unit. Baker Hughes. Hummingbird all-electric land cementing unit | Baker Hughes

Transform your land operations with the first fully electric-powered cementing unit. Hummingbird all-electric land cementing unit. Baker Hughes. Transform your land operations with the first fully electric-powered cementing unit: Hummingbird all-electric land cementing unit