big win

Rice University team breaks records with new sunlight-to-hydrogen device

Rice University engineers have created a device that absorbs light, converts it into electricity, and then uses the electricity to split water molecules and generate hydrogen. Photo courtesy Gustavo Raskoksy/Rice University

A team of Rice University engineers have developed a scalable photoelectrochemical cell that converts sunlight into clean hydrogen at a record-setting pace.

The lab led by Aditya Mohite, an associate professor at Rice, published the findings in a study in Nature Communications late last month, in collaboration with the National Renewable Energy Laboratory, which is backed by the Department of Energy. In it, the team details how they created a device that absorbs light, converts it into electricity, and then uses the electricity to split water molecules and generate hydrogen.

Austin Fehr, a chemical and biomolecular engineering doctoral student at Rice and one of the study’s lead authors, says in a statement that the device "could open up the hydrogen economy and change the way humans make things from fossil fuel to solar fuel."

The device has a high solar-to-hydrogen conversion efficiency rate of 20.8 percent, which has yet to be reached with this type of technology, according to a release from Rice. In addition to its speed, this device is groundbreaking because it uses low-cost metal-halide perovskite semiconductors to power the reaction.

A photoreactor developed by Rice University’s Mohite research group and collaborators achieved a 20.8 percent solar-to-hydrogen conversion efficiency. Photo courtesy Gustavo Raskoksy/Rice University

“Using sunlight as an energy source to manufacture chemicals is one of the largest hurdles to a clean energy economy,” Fehr says in the statement. “Our goal is to build economically feasible platforms that can generate solar-derived fuels. Here, we designed a system that absorbs light and completes electrochemical water-splitting chemistry on its surface.”

To create the device the Mohite lab turned their existing solar cell into a reactor to split water into oxygen and hydrogen. However they continued running into issues with the semiconductors being "extremely unstable in water," according to Rice.

After two years of trials and errors, the team uncovered that by adding two layers of barriers to the semiconductors they were able to reach these record-breaking efficiency rates.

The team has also shown uses for their double barrier design with different semiconductors and for different reactions.

“We hope that such systems will serve as a platform for driving a wide range of electrons to fuel-forming reactions using abundant feedstocks with only sunlight as the energy input,” Mohite says in the statement.

The device joins another game-changing product shared in a Rice research study in recent weeks. Last month, a Rice University lab led by Haotian Wang, the William Marsh Rice Trustee Chair and an associate professor at Rice, shared their findings on how their simple plug-and-play device removes carbon dioxide from air capture to induce a water-and-oxygen-based electrochemical reaction.

Rice also recently opened registration for its 20th anniversary of Energy Tech Venture Day. Click here to register for the event on Sept. 21.

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A View From HETI

A major heat alert is in place for Texas. Photo via Getty Images

Although the first official day of summer is not until June 20, Houstonians are already feeling the heat with record-breaking, triple-digit temperatures. The recent heatwave has many Texans wondering if the state’s grid will have enough power to meet peak demand during the summer.

How the Texas grid fared in summer 2024

To predict what could happen as we enter summer this year, it is essential to assess the state of the grid during summer 2024, and what, if anything, has been improved.

According to research from the Federal Reserve Bank of Dallas, solar electricity generation and utility-scale batteries within the ERCOT power grid set records in summer 2024. On average, solar contributed nearly 25 percent of total power needs during mid-day hours between June 1 and August 31. In critical evening hours, when load (demand for electricity) remains elevated but solar output declines, discharge from batteries successfully filled the gap.

Texas added more battery storage capacity than any other state last year, and, excluding California, now has more battery capacity than the rest of the country combined. The state also added 3,410 megawatts of natural gas-fueled power last year. While we did experience major power losses as a result of extreme weather, such as the derecho in May and Hurricane Beryl in July, ERCOT did not have to issue a single conservation appeal last summer to ward off capacity-related outages--and it was the sixth-hottest summer on record.

Policymakers are also taking steps to pass legislation that will help stabilize the grid. During this year’s 89th legislative session, Senate Bill 6 (TX SB6) was introduced, which seeks to:

  • Improve ERCOT's load forecasting transparency
  • Enhance outage protections for residential consumers
  • Adjust transmission cost allocations
  • Bolster grid reliability

In essence, the bill is meant to balance business growth with grid reliability, ensuring that the state continues to be an attractive destination for industrial expansion while preventing reliability risks due to rapid demand increases.

Is the Texas grid prepared for summer 2025?

The good news is that the grid is predicted to be able to manage the energy demand this summer, but there is no guarantee that power disruptions will not happen.

The National Oceanic and Atmospheric Administration has indicated that summer 2025 will likely be warmer and drier than average across most of Texas. Based on ERCOT data and weather projections, West Texas and the Dallas-Fort Worth and Houston metropolitan areas face the highest risk of outages.

While Texas is No. 1 in wind power and No. 2 in solar power, only behind California, there are valid concerns about heavy reliance on renewables when the wind isn’t blowing or the sun isn’t shining, compounded by a lack of large-scale battery storage. Then, there’s the underlying cost and ecological footprint associated with the manufacturing of those batteries. Although solar and wind capacity continues to expand rapidly, integration challenges remain during peak demand periods, especially during the late afternoon when solar generation declines but air conditioning usage remains high.

Additional factors that contribute to the grid’s instability are that Texas faces a massive surge in demand for electricity due to an increase in large users like crypto mining facilities and data centers, as well as population growth. ERCOT predicts that Texas’ energy demand will nearly double by 2030, with power supply projected to fall short of peak demand in a worst-case scenario beginning in summer 2026.

Thanks to investments in solar power, battery storage, and traditional energy sources, ERCOT has made progress in improving grid reliability which indicates that, at least for this summer, energy load will be manageable. A combination of legislative action, strategic planning and technological innovation will need to continue to ensure that this momentum remains on a positive trajectory.

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Sam Luna is director at BKV Energy, where he oversees brand and go-to-market strategy, customer experience, marketing execution, and more.

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