This is the third in a series of articles I’m writing about flow battery technology, with a couple of articles devoted to Agora Energy Technologies’ specific technology. The first article dealt with flow batteries in general, and why they are a strongly promising component for grid storage. The second dealt with Agora’s unique differentiators. This article is devoted to a compelling alternative use case for their technology, one that’s immediate and high value.
The past three years have been a deeper dive into industrial processes and chemical engineering for me, and the implications for global warming. The CleanTechnica report on Carbon Engineering was a major effort, as were the many articles on industrial processes for carbon sequestration. The assessment of cement manufacturing, with and without the nonsensical use of concentrating solar power was another.
This has led me to a deeper interest in the edge cases of climate solutions. My assessments and research over the past few years has led me to understand the major solution sets for energy, transportation, and biological carbon sequestration, but there’s still a lot of carbon and pollution emitted in industrial processes that needs to be addressed. As one example, there is the $44 billion global carbonates market.
Potassium carbonate is in a lot of things we use daily. It’s used in soaps, glass, and china dishes. It’s used as a drying agent in chemical processes. It’s in both Asian noodles and Dutch cocoa powder. Wine makers use it. It’s a water softener and a fire extinguisher. It’s used in welding and animal feed.
Sodium carbonate is equally widely used. It’s in glass, paper, rayon, soaps, and detergents. It’s used for water softening. It’s a food additive that controls acidity. As a weak, safe to handle base, it’s used in a lot of chemical processes. Over 40 million metric tons are produced each year, amounting to several kilograms for every person on Earth.
Between them, they represent a roughly $44 billion global annual market. And the current processes that make them are pretty nasty in a lot of ways.
Let’s take sodium carbonate as an example. About 75% of all the sodium carbonate used in the world is made by the Solvay Process. The US gets most of its sodium carbonate from a massive trona deposit in Wyoming.
The Solvay Process was invented in 1861, and is still used everywhere today. It bubbles CO2 up through ammonia-based brine in a four-step chemical engineering process that produces and uses CO2 at various points in the process. And of course there’s the ammonia, which is highly toxic, with 15-minute exposure limits to levels of 35 ppm of gaseous ammonia per the US Occupational Safety and Health Administration. Ammonia is a manufactured substance in and of itself, using hydrogen created from fossil fuels today with 8-35 times the mass of CO2 as hydrogen. Prolonged exposure to small amounts of ammonia cause irreversible health effects. The ammonia is mostly recycled with only small amounts being lost, but eliminating it entirely would be beneficial.
The Solvay process actually captures some CO2 produced in one step to use in a later stage, but overall, the deployed process is a net emitter of 2.74 times the mass of CO2 as the mass of carbonates produced.
The source of heat in the first step interested me. That step in the process is the same as for cement, incidentally. It requires substantial heat, in the 600 to 1000 degree Celsius range to calcinate limestone to make quicklime and CO2. Some of the CO2 and all of the quicklime are used in later steps in the process, unlike cement making where all the CO2 is just emitted into the atmosphere.
As a side note, a Lafarge cement expert told me when I was exploring cement that they had no good process for capturing limestone kiln CO2 emissions, which clearly isn’t the case as it has been done as an industrial process for 160 years. Capturing flue CO2 isn’t hard, it’s just expensive, so it isn’t done unless there’s a very good economic reason.
Then there’s another temperature challenge, which is that the third step in the process is strongly exothermic, which means it gives off a lot of heat, just not usefully. One of the key challenges in the process is keeping the temperature low enough. That’s typically done with cooling water from ground sources, a challenged source in many parts of the world today, with thermal generation plants shutting down or running on diminished capacity as ground water heats up past the point where it works well with the designed equipment. The Solvay company shut down four of its 22 Sao Paulo, Brazil units due to the river they take water from drying up in 2014, a taste of the future for many heavy water consuming industrial plants located on water sources at risk from global warming.
The second instance of the application of heat in step 4 is also interesting. That requires another kiln with a temperature of about 300 degrees Celsius. Any time I see heat these days in industrial processes, I assume it’s coming from fossil fuels, and I was unsurprised to find that the preferred energy source for the Solvay Process was coke, a processed coal derivative.
That’s not all of course. The Solvay Process is much less polluting than the Leblanc Process it replaced, but inland sites end up with 50% more waste deposits of by-products than the sodium carbonates of value. Solvay, New York, which was renamed when the Solvay company built a plant there, has massive waste beds that have polluted the local area and contributed to the nearby Onondaga Lake being declared a Superfund Site.
I haven’t done the same assessment of the environmental impacts of the US trona mining and processing sodium carbonate stream, but at first glance it looks like a high CO2 emitter with a fair amount of use of toxic chemicals and a challenging waste stream as well.
Why is this digression interesting? Well, the Agora technology can create sodium carbonate in two steps without any heat and with barely any temperature management required.
Wait. What? It’s a battery, not a chemical plant, isn’t it?
Well, yes. The closed-loop model cycles the chemicals between their base form and their charged form and back. But the open-loop model, which changes in some of the details, produces sodium carbonate after the second cycle instead of turning it back into CO2, in a up to 35% by weight solution with water. And both act as batteries, taking in electricity in the charging stage and producing electricity in the discharge phase.
So the ammonia-based, high-heat, high-cooling, five-step process turns into a shorter process with much less harmful outcomes. It takes electricity when it’s cheap at night or other times, from renewables wherever possible of course, to ‘charge’ the battery. Then during the daytime, instead of reversing the process as in the open-flow approach, it sends it through Agora’s cells with a different chemistry and produces carbonates in solution and electricity. The entire daytime process from lights to pumps to drying the carbonate solution and the like can be run by a portion of the electricity that’s produced.
The output sodium carbonate is pure as well. It’s a pure compound in pure water. Heat the water to evaporate it off, and the purity should be well over the 98% purity typically guaranteed for food additives for the most expensive variants. There’s enough electricity in the battery to power the evaporation directly per my calculations with the CEO Dr Christina Gyenge, but there’s far more than enough to use heat pump technology with a COP of 4 to do that, or to pump it over a source of waste industrial heat elsewhere, and leave a lot of electricity left over for other uses in the industrial facility or to sell to the grid.
So, this technology can take a cheap feedstock we have too much of in the world, CO2, regardless of where it comes from and using renewable electricity produce very high quality industrial chemicals that are used globally in a market worth tens of billions of dollars.
Agora’s CO2-based redox flow battery technology is an industrial component from the future.
Full disclosure. I have a professional relationship with Agora as a strategic advisor and Board observer. I did an initial strategy session with Agora about their redox flow battery technology in late 2019 and was blown away by what they had in hand, and my formal role with the firm started at the beginning of 2021. I commit to being as objective and honest as always, but be aware of my affiliation.
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Japanese equipment giant Kubota brought 22 new or updated machines to the 2025 bauma expo earlier this year, but tucked away in the corners was a new retrofit kit that can help existing customers decarbonize more quickly, and more affordably.
The latest equipment maker to put its name on the retrofit list is Kubota, who says its kit can be installed by a trained dealer in a single day.
That’s right! By this time tomorrow, your diesel-powered Kubota KX019 or U27-4 excavator (shown) could be fitted with an 18 or 20 kWh li-ion battery pack and electric drive motors and ready to get to work in a low-noise or low-vibration work environment where emissions are a strict no-no. Think indoor precision demolition or historic archeological excavation.
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Then, if necessary, it can go right back to diesel power.
Kubota says its modular retrofit kits is a response to the increasing global demand for sustainable alternatives by focusing on making machinery that’s flexible and repairable enough to be “reusable,” and offer construction fleet managers a longer operational lifespan, superior ROI (return on investment), and lower TCO (total cost of ownership) than the competition.
Kubota’s solution also notably reduces maintenance costs and operational overheads. With no engine and associated components, servicing time and expenses are considerably reduced, saving customers both time and money. Additionally, with electricity costing far less than fossil fuels, it offers a highly economical advantage.
International Rental News reports that other changes to the excavators include a more modern cab controls with a digital instrument cluster, a 60 mm wider undercarriage for more stability, and an independent travel circuit allows operators to use the boom, dipper, bucket, and auxiliary functions without an impact on tracking performance.
Kubota’s new kit, first shown at last year’s Hillhead exhibition in the UK, will officially be on sale this summer – any day now, in fact – though pricing has yet to be announced.
Electrek’s Take
If you’re wondering how it is that we’re still talking about bauma 2025 a full quarter after the show wrapped up, then I haven’t done a good enough job of explaining how positively massive the show was. Check out this Quick Charge episode (above) then let us know what you think of Kubota’s modular power kits in the comments.
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Elon Musk isn’t happy about Trump passing the Big Beautiful Bill and killing off the $7,500 EV tax credit – but there’s a lot more bad news for Tesla baked into the BBB. We’ve got all that and more on today’s budget-busting episode of Quick Charge!
We also present ongoing coverage of the 2025 Electrek Formula Sun Grand Prix and dive into some two wheeled reports on the new electric Honda Ruckus e:Zoomer, the latest BMW electric two-wheeler, and more!
New episodes of Quick Charge are recorded, usually, Monday through Thursday (and sometimes Sunday). We’ll be posting bonus audio content from time to time as well, so be sure to follow and subscribe so you don’t miss a minute of Electrek’s high-voltage daily news.
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If you’re considering going solar, it’s always a good idea to get quotes from a few installers. To make sure you find a trusted, reliable solar installer near you that offers competitive pricing, check out EnergySage, a free service that makes it easy for you to go solar. It has hundreds of pre-vetted solar installers competing for your business, ensuring you get high-quality solutions and save 20-30% compared to going it alone. Plus, it’s free to use, and you won’t get sales calls until you select an installer and share your phone number with them.
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Solar and wind accounted for almost 96% of new US electrical generating capacity added in the first third of 2025. In April, solar provided 87% of new capacity, making it the 20th consecutive month solar has taken the lead, according to data belatedly posted on July 1 by the Federal Energy Regulatory Commission (FERC) and reviewed by the SUN DAY Campaign.
Solar’s new generating capacity in April 2025 and YTD
In its latest monthly “Energy Infrastructure Update” report (with data through April 30, 2025), FERC says 50 “units” of solar totaling 2,284 megawatts (MW) were placed into service in April, accounting for 86.7% of all new generating capacity added during the month.
In addition, the 9,451 MW of solar added during the first four months of 2025 was 77.7% of the new generation placed into service.
Solar has now been the largest source of new generating capacity added each month for 20 consecutive months, from September 2023 to April 2025.
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Solar + wind were >95% of new capacity in 1st third of 2025
Between January and April 2025, new wind provided 2,183 MW of capacity additions, accounting for 18.0% of new additions in the first third.
In the same period, the combination of solar and wind was 95.7% of new capacity while natural gas (511 MW) provided just 4.2%; the remaining 0.1% came from oil (11 MW).
Solar + wind are >22% of US utility-scale generating capacity
The installed capacities of solar (11.0%) and wind (11.8%) are now each more than a tenth of the US total. Together, they make up almost one-fourth (22.8%) of the US’s total available installed utility-scale generating capacity.
Moreover, at least 25-30% of US solar capacity is in small-scale (e.g., rooftop) systems that are not reflected in FERC’s data. Including that additional solar capacity would bring the share provided by solar + wind to more than a quarter of the US total.
With the inclusion of hydropower (7.7%), biomass (1.1%), and geothermal (0.3%), renewables currently claim a 31.8% share of total US utility-scale generating capacity. If small-scale solar capacity is included, renewables are now about one-third of total US generating capacity.
Solar is on track to become No. 2 source of US generating capacity
FERC reports that net “high probability” additions of solar between May 2025 and April 2028 total 90,158 MW – an amount almost four times the forecast net “high probability” additions for wind (22,793 MW), the second-fastest growing resource. Notably, both three-year projections are higher than those provided just a month earlier.
FERC also foresees net growth for hydropower (596 MW) and geothermal (92 MW) but a decrease of 123 MW in biomass capacity.
Taken together, the net new “high probability” capacity additions by all renewable energy sources over the next three years – i.e., the bulk of the Trump administration’s remaining time in office – would total 113,516 MW.
FERC doesn’t include any nuclear capacity in its three-year forecast, while coal and oil are projected to contract by 24,373 MW and 1,915 MW, respectively. Natural gas capacity would expand by 5,730 MW.
Thus, adjusting for the different capacity factors of gas (59.7%), wind (34.3%), and utility-scale solar (23.4%), electricity generated by the projected new solar capacity to be added in the coming three years should be at least six times greater than that produced by the new natural gas capacity, while the electrical output by new wind capacity would be more than double that by gas.
If FERC’s current “high probability” additions materialize, by May 1, 2028, solar will account for one-sixth (16.6%) of US installed utility-scale generating capacity. Wind would provide an additional one-eighth (12.6%) of the total. That would make each greater than coal (12.2%) and substantially more than nuclear power or hydropower (7.3% and 7.2%, respectively).
In fact, assuming current growth rates continue, the installed capacity of utility-scale solar is likely to surpass that of either coal or wind within two years, placing solar in second place for installed generating capacity, behind only natural gas.
Renewables + small-scale solar may overtake natural gas within 3 years
The mix of all utility-scale (ie, >1 MW) renewables is now adding about two percentage points each year to its share of generating capacity. At that pace, by May 1, 2028, renewables would account for 37.7% of total available installed utility-scale generating capacity – rapidly approaching that of natural gas (40.1%). Solar and wind would constitute more than three-quarters of installed renewable energy capacity. If those trend lines continue, utility-scale renewable energy capacity should surpass that of natural gas in 2029 or sooner.
However, as noted, FERC’s data do not account for the capacity of small-scale solar systems. If that’s factored in, within three years, total US solar capacity could exceed 300 GW. In turn, the mix of all renewables would then be about 40% of total installed capacity while the share of natural gas would drop to about 38%.
Moreover, FERC reports that there may actually be as much as 224,426 MW of net new solar additions in the current three-year pipeline in addition to 69,530 MW of new wind, 9,072 MW of new hydropower, 202 MW of new geothermal, and 39 MW of new biomass. By contrast, net new natural gas capacity potentially in the three-year pipeline totals just 26,818 MW. Consequently, renewables’ share could be even greater by mid-spring 2028.
“The Trump Administration’s ‘Big, Beautiful Bill’ … poses a clear threat to solar and wind in the years to come,” noted the SUN DAY Campaign’s executive director, Ken Bossong. “Nonetheless, FERC’s latest data and forecasts suggest cleaner and lower-cost renewable energy sources may still dominate and surpass nuclear power, coal, and natural gas.”
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