Led by Haotian Wang (left) and Feng-Yang Chen, the Rice University team published a study this month detailing how its reactor system sustainably converts waste into ammonia. Photo by Jeff Fitlow/Rice University

A team of Rice University engineers has developed a reactor design that can decarbonize ammonia production, produce clean water and potentially have applications in further research into other eco-friendly chemical processes.

Led by Rice associate professor Haotian Wang, the team published a study this month in the journal Nature Catalysis that details how the new reactor system sustainably and efficiently converts nitrates (common pollutants found in industrial wastewater and agricultural runoff) into ammonia, according to the university. The research was supported by Rice and the National Science Foundation.

“Our findings suggest a new, greener method of addressing both water pollution and ammonia production, which could influence how industries and communities handle these challenges,” Wang says in a statement. “If we want to decarbonize the grid and reach net-zero goals by 2050, there is an urgent need to develop alternative ways to produce ammonia sustainably.”

Other methods of creating ammonia include the Haber-Bosh process and electrochemical synthesis. The Haber-Bosh process requires large-scale centralized infrastructure and high temperature and pressure conditions. Meanwhile, electrochemical synthesis requires a high concentration of additive chemicals.

According to Rice, the new reactor requires less additive chemicals than the electrochemical synthesis, allowing nitrates to be converted more sustainably. The reactor relies on an innovative porous solid electrolyte as well as recyclable ions and a three-chamber system to improve the reaction’s efficiency.

Additionally, this development provides an effective water decontamination method.

“We conducted experiments where we flowed nitrate-contaminated water through this reactor and measured the amount of ammonia produced and the purity of the treated water,” Feng-Yang Chen, a Rice graduate student who is the lead author on the study, says. “We discovered that our novel reactor system could turn nitrate-contaminated water into pure ammonia and clean water very efficiently, without the need for extra chemicals. In simple terms, you put wastewater in, and you get pure ammonia and purified water out.”

Pedro Alvarez, the George R. Brown Professor of Civil and Environmental Engineering, director of the Nanosystems Engineering Research Center for Nanotechnology-Enabled Water Treatment (NEWT) and the Water Technologies Entrepreneurship and Research (WaTER) Institute at Rice, says the reactor is "very timely and important" for growing cities that must deal with nitrate-contaminated groundwater supplies it.

"Conventional nitrate removal in drinking water treatment involves ion exchange or membrane filtration by reverse osmosis, which generates brines and transfers the nitrate problem from one phase to another,” he continues.

Wang's lab has been making headlines in recent years for innovative processes and technologies focused on the energy transition.

Last year, the lab published a study in Nature detailing a new technology that uses electricity to remove carbon dioxide from air capture to induce a water-and-oxygen-based electrochemical reaction, generating between 10 to 25 liters of high-purity carbon using only the power of a standard lightbulb.

In 2022, Rice reported that Wang’s lab in the George R. Brown School of Engineering had also replaced rare, expensive iridium with ruthenium, a more abundant precious metal, as the positive-electrode catalyst in a reactor that splits water into hydrogen and oxygen.

The lab received a portion of $10.8 million in research grants from the Houston-based Welch Foundation for research focused on converting carbon dioxide into useful chemicals, such as ethanol, last year. And Solidec, founded by Ryan Duchanois and Yang Xia from Wang's Lab, also received a $100,000 award from Rice as part of the One Small Step Grant program.

Wang has also been named among one of the most-cited researchers in the world.
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Houston energy company to invest $1B in U.S. electric grid manufacturing

grid boost

Hitachi Energy, whose U.S. headquarters is in Houston, has earmarked more than $1 billion to manufacture infrastructure for the U.S. electric grid, which is coping with greater power demand from data centers and AI platforms.

Of that sum, $457 million is dedicated to building a power transformer factory in Virginia. Hitachi Energy said it’ll be the largest facility of its kind in the U.S.

“Power transformers are a linchpin technology for a robust and reliable electric grid and winning the AI race. Bringing production of large power transformers to the U.S. is critical to building a strong domestic supply chain for the U.S. economy and reducing production bottlenecks, which is essential as demand for these transformers across the economy is surging,” said Andreas Schierenbeck, CEO of Switzerland-based Hitachi Energy, which generates revenue of about $16 billion.

The Hitachi announcement aligns with various priorities of the Trump administration. The White House is promoting more U.S.-based manufacturing, more power to accommodate data centers and AI, and greater use of U.S. energy resources.

“If we are going to win the AI race, reindustrialize, and keep the lights on, America is going to need a lot more reliable energy,” U.S. Energy Secretary Chris Wright said.

Texas still has its best solar days ahead of it, even as federal tax credit sunsets

Guest Column

If you follow energy policy, you already know that Congress repealed the 30% residential solar tax credit. This poses a significant challenge for continued growth in the market. It also provides an opportunity for the industry to grow in a smart, consumer-friendly way. That’s why in Texas, the story is what happens next: The state and the market are continuing to make going solar much simpler, better, and cheaper.

Policies are moving in the right direction. For example, starting this month, a bipartisan permitting reform takes effect that will cut red tape for home solar and batteries. It lets licensed third-party professionals review plans and perform inspections, requires agencies to post standardized rules and fees online, and allows homeowners to start work once those third-party approvals are submitted. It also shifts negligence liability to the third-party reviewer, thereby reducing municipal risk while accelerating safe, code-compliant installs. In plain English: fewer bottlenecks, faster installs, and lower “soft costs.”

As a result, Houston is already piloting the National Renewable Energy Lab’s free SolarAPP+ to auto-approve standard solar designs, which cuts roughly 12 days from typical timelines. Independent analyses estimate that these automated permitting rules could trim rooftop solar costs by thousands. In other words, even small, costless policy changes like this can save you almost as much money as the huge solar tax credit did, and these great reforms are happening all the time, and they make the process much more convenient and reliable.

While Texas is making solar simpler, it’s also helping consumers have a good experience when going solar. As of this month, Texas law now also requires solar salespeople to register with the Texas Department of Licensing and Regulation. The same bill standardizes contracts and provides for mandatory disclosures of upfront cost and financing terms. The whole solar industry benefits when customers have a good solar experience. Word of mouth is vital to keeping solar shining.

There's yet another pro-solar Texas law that's also going into effect this month: in addition to SB 1202 (streamlining solar permits) and SB 1036 (regulating solar sales tactics), the legislature is also supporting the dissemination of information about your options when going solar via SB 1697. You can read more about these three brand-new pro-solar state laws here.

The end of the solar tax credit is not the end of the solar industry. Far from it.

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Dori Wolf is Senior Texas Program Associate for Solar United Neighbors, a vendor and neutral nonprofit with more than 15 years helping people go solar. Their free Solar Help Desk walks you through the details. Also check out their Go Solar Guide and Solar Owner’s Manual.

Solar United Neighbors also helps you find the best retail electricity plan through its partnership with Texas Power Guide.

Sunnova assets officially sold as founder launches new Houston energy startup

solar shift

Solaris Assets has completed its acquisition of the majority of Sunnova Energy International’s residential solar assets. Houston-based Sunnova filed for Chapter 11 bankruptcy this summer after piling up billions of dollars in debt.

Meanwhile, Sunnova founder and former CEO John Berger has launched a Houston-based home energy services startup, Otovo USA, which just received more than $4 million in seed funding.

Solaris now owns Sunnova’s residential solar services platform and its solar generation and storage portfolio, along with leases, loans and power purchase agreements. Sunnova’s operations are being shifted to SunStrong Management, an Austin-based asset manager for the renewable energy sector.

“By bringing together SunStrong’s asset management expertise with Sunnova’s nationally scaled customer base, we are creating a stronger, more capable leader in the solar industry,” Brendon Merkley, CEO of SunStrong, said in a news release. “Our priority is to maintain the highest levels of service for customers as we expand our footprint as a premier solar asset servicer.”

In June, Sunnova sold its new-home business to homebuilder Lennar for $15.2 million and sold certain assets to investment firm Atlas SP Partners for $15 million.

As of December, Sunnova’s debt totaled nearly $10.7 billion, Reuters reported. Sunnova faced numerous challenges in its quest to survive, including higher interest rates, the reduction of solar incentives in California, and a shakeup in federal subsidies for renewable energy.

Sunnova filed for Chapter 11 bankruptcy in June. A month later, a bankruptcy judge approved the court-supervised sale of Sunnova. Solaris’ acquisition of Sunnova closed Sept. 3.

As SunStrong absorbs the bulk of Sunnova’s assets, Berger — who quit in March as Sunnova’s CEO — has formed a new business. He’s now the founder and CEO of Otovo USA, a partner of European residential power company Otovo.

Otovo USA offers solar power systems, solar batteries, standby generators, EV chargers, electric-load managers, and other power generation and management systems. Otovo’s AI-supported offerings are now available in Texas; the company plans to expand nationwide.

Otovo USA raised its seed funding from the EIC Rose Rock Venture Fund, which invests in energy startups.

“Otovo USA is here to help the millions of Americans with home energy services that are fed up with the complexities of warranties, juggling multiple vendors, and long repair times,” Berger said. The startup, he added, “is bringing customers what they really need: reliable power and a single partner accountable for keeping it up and running. It’s your power, backed by ours.”