In a recent Energy Tech Startups Podcast episode, Cindy Taff discussed the evolution of Sage GeoSystems, the challenges of scaling hard tech solutions, and the opportunities presented by geothermal and pumped hydro energy storage. Photo courtesy of Sage

Cindy Taff, co-founder and CEO of Sage GeoSystems, has emerged as a visionary leader in the energy transition, recently named to Time magazine’s 100 Most Influential Climate Leaders in Business for 2024. Under her leadership, Sage is not only advancing geothermal energy innovation but also redefining how energy storage can support a renewable-powered grid.

In a recent Energy Tech Startups Podcast episode, Taff discussed the evolution of Sage GeoSystems, the challenges of scaling hard tech solutions, and the opportunities presented by geothermal and pumped hydro energy storage. Her insights reflect the unique perspective of a founder bridging oil and gas expertise with renewable energy innovation.

- YouTubeCindy shares how Sage Geosystems is leveraging its oil and gas expertise to develop groundbreaking subsurface pumped hydro ...

Breaking Boundaries with Geopressured Geothermal Systems

Sage GeoSystems is at the forefront of next-generation geothermal energy, advancing Geopressured Geothermal Systems (GGS) that can be deployed in a wide range of geographies. Unlike traditional geothermal systems, which rely on natural water reservoirs near volcanic activity, Sage’s engineered reservoirs allow geothermal energy to be tapped almost anywhere.

“Geothermal energy is no longer restricted to specific conditions,” Taff explained. “Our systems are flexible, scalable, and capable of meeting the needs of energy-intensive applications like data centers—including a recent deal with Meta to deliver 150 megawatts of geothermal power for their facilities.”

This adaptability sets Sage apart, offering a path to reliable, clean energy that can complement intermittent sources like wind and solar. Sage also secured a win in the Energy Transition Business category alongside notable finalists like Amperon and Tierra Climate, underscoring its leadership in innovative energy solutions.

Pivoting Toward Subsurface Energy Storage

While initially focused solely on geothermal, Sage uncovered a transformative opportunity in subsurface pumped hydro energy storage during field trials. Dubbed “upside-down pumped hydro,” the solution provides long-duration energy storage capable of balancing the grid for 17+ hours—far surpassing the capabilities of lithium-ion batteries for extended periods.

“Pumped storage hydropower is a critical piece of the energy puzzle,” Taff emphasized. By storing energy during off-peak times and releasing it when solar and wind aren’t producing, Sage is helping bridge the intermittency gap in renewables. This approach positions pumped storage as a game-changer for a reliable, clean energy grid.

Lessons from the Founder’s Journey

Taff’s transition from a 35-year career at Shell to geothermal entrepreneurship offers valuable lessons for founders in capital-intensive industries:

  1. Leverage Expertise, but Stay Open to New Solutions:
    Taff’s oil and gas background enabled her to approach geothermal with deep technical knowledge, but Sage’s pivot to energy storage illustrates the importance of staying adaptable during development.
  2. Educate Financial Stakeholders:
    Securing funding for hard tech remains a challenge. “Investors often lack the subsurface knowledge needed to understand our technology,” Taff explained. She emphasized the need to bring on team members who can translate technical innovation into financial terms.
  3. Be Ready for Capital-Intensive Scaling:
    With geothermal plants costing millions to build, startups must carefully manage capital and timelines. Taff encourages founders to seek strategic investors, like Chesapeake Energy, who understand the challenges and potential of scaling infrastructure.

Beyond Geothermal: A Call for Pumped Storage Hydropower

In addition to geothermal, Taff champions pumped storage hydropower as an underutilized climate solution. “While lithium-ion batteries get a lot of attention, pumped storage hydropower offers long-duration storage that can stabilize the grid for days, not just hours,” she said.

By storing excess energy during off-peak times and releasing it when solar and wind aren’t producing, pumped storage hydropower can play a critical role in balancing renewables. Sage GeoSystems is uniquely positioned to integrate this technology into a broader energy strategy, offering sustainable and scalable solutions for energy-intensive industries.

A Vision for Geothermal and the Energy Transition

Looking ahead, Taff sees geothermal energy and storage as critical components of a sustainable energy mix. “We’re still in the early stages, but geothermal is following a trajectory similar to wind and solar 15 years ago,” she said. Sage’s innovative approaches are paving the way for geothermal to become a scalable, competitive solution, capable of powering industries and data centers while providing energy storage that stabilizes the grid.

With her recognition by Time magazine and a recent deal with Meta, Sage GeoSystems is proving that geothermal energy can be a powerful ally in achieving global decarbonization goals. The company’s innovative Geopressured Geothermal Systems and subsurface storage solutions are laying the groundwork for a reliable and sustainable energy future.

Listen to the full episode with Cindy Taff on the Energy Tech Startups Podcast here.

Energy Tech Startups Podcast is hosted by Jason Ethier and Nada Ahmed. It delves into Houston's pivotal role in the energy transition, spotlighting entrepreneurs and industry leaders shaping a low-carbon future.


These three Houston innovators have been recognized by Time Magazine. Photos courtesy

3 Houstonians named to prestigious list of climate leaders

who's who

Three Houston executives — Andrew Chang, Tim Latimer, and Cindy Taff — have been named to Time magazine’s prestigious list of the 100 Most Influential Climate Leaders in Business for 2024.

As managing director of United Airlines Ventures, Chang is striving to reduce the airline’s emissions by promoting the use of sustainable aviation fuel (SAF). Jets contribute to about two percent of global emissions, according to the International Energy Agency.

In 2023, Chang guided the launch of the Sustainable Flight Fund, which invests in climate-enhancing innovations for the airline sector. The fund aims to boost production of SAF and make it an affordable alternative fuel, Time says.

Chang tells Time that he’d like to see passage of climate legislation that would elevate the renewable energy sector.

“One of the most crucial legislative actions we could see in the next year is a focus on faster permitting processes for renewable energy projects,” Chang says. “This, coupled with speeding up the interconnection queue for renewable assets, would significantly reduce the time it takes for clean energy to come online.”

At Fervo Energy, Latimer, who’s co-founder and CEO, is leading efforts to make geothermal power “a viable alternative to fossil fuels,” says Time.

Fervo recently received government approval for a geothermal power project in Utah that the company indicates could power two million homes. In addition, Fervo has teamed up with Google to power the tech giant’s energy-gobbling data centers.

In an interview with Time, Latimer echoes Chang in expressing a need for reforms in the clean energy industry.

“Addressing climate change is going to require us to build an unprecedented amount of infrastructure so we can replace the current fossil fuel-dominated systems with cleaner solutions,” says Latimer. “Right now, many of the solutions we need are stalled out by a convoluted permitting and regulatory system that doesn’t prioritize clean infrastructure.”

Taff, CEO of geothermal energy provider Sage Geosystems, oversees her company’s work to connect what could be the world’s first geopressured geothermal storage to the electric grid, according to Time. In August, Sage announced a deal with Facebook owner Meta to produce 150 megawatts of geothermal energy for the tech company’s data centers.

Asked which climate solution, other than geothermal, deserves more attention or funding, Taff cites pumped storage hydropower.

“While lithium-ion batteries get a lot of the spotlight, pumped storage hydropower offers long-duration energy storage that can provide stability to the grid for days, not just hours,” Taff tells Time. “By storing excess energy during times of low demand and releasing it when renewables like solar and wind are not producing, it can play a critical role in balancing the intermittent nature of renewables. Investing in pumped storage hydropower infrastructure could be a game-changer in achieving a reliable, clean energy future.”

Clockwise from top left: Sean Kelly of Amperon, Dianna Liu of ARIXTechnologies, Matthew Dawson of Elementium Materials, Vibhu Sharma of InnoVent Renewables, Cindy Taff of Sage Geosystems, and Emma Konet of TierraClimate. Photos courtesy

Houston's top energy transition founders explain their biggest challenges

overheard

From finding funding to navigating the pace of traditional oil and gas company tech adoption, energy transition companies face their fair share of challenges.

This year's Houston Innovation Awards finalists in the Energy Transition category explained what their biggest challenge has been and how they've overcome it. See what they said below, and make sure to secure your tickets to the Nov. 14 event to see which of these finalists win the award.

"The evolving nature of the energy industry presents opportunities to solve some of our industry's greatest challenges. At Amperon we help optimize grid reliability and stability with the power of AI demand forecasting." 

Sean Kelly, CEO of Amperon, an AI platform powering the smart grid of the future

"The biggest challenge in leading an energy transition-focused startup has been balancing the urgency for sustainable solutions with the slow pace of change in traditional industries like oil and gas. Many companies are cautious about adopting new technologies, especially when it comes to integrating sustainability initiatives. We overcame this by positioning our solutions not just as environmentally friendly, but as tools that improve safety, efficiency, and cost savings. By aligning our value proposition with their operational goals and demonstrating real, measurable benefits, we were able to gain traction and drive adoption in industries that are traditionally resistant to change." 

— Dianna Liu, CEO of ARIXTechnologies, an integrated robotics and data analytics company that delivers inspection services through its robotics platforms

"Scaling up production of hard tech is a major challenge. Thankfully, we recruited top-notch talent with experience in technology scale-up and chemical processes. In addition, we've begun building partnerships with some of the world's largest chemical manufacturers in our space who are excited to be a part of our journey and could rapidly accelerate our go to market strategy. We have significant demand for our product as early as 2025, so partnering with these companies to scale-up will bring our technology to market years ahead of doing it alone."

— Matthew Dawson, CEO of Elementium Materials, a battery technology with liquid electrolyte solutions

"Our pyrolysis reactor is a proprietary design that was developed during Covid. We ran simulations to prove that it works, but it was not easy to test it in a pilot facility, let alone scaling it up. We managed ... to run our pilot plant studies, while working with them remotely. We proved that our reactor worked and produced high quality products. Later, we built our own pilot plant R&D facility to continue running tests and optimizing the process. Then, there was the challenge of scaling it up to commercial size. ... We put together a task force of four different companies to come together to design and build this complex reactor in record time."

— Vibhu Sharma, CEO of InnoVentRenewables, a startup with proprietary continuous pyrolysis technology that converts waste tires, plastics, and biomass into valuable fuels and chemicals

"Energy storage and geothermal power generation are capital-intensive infrastructure projects, requiring investors with a deep commitment and the patience in terms of years to allow the technology to be developed and proven in the field. One challenge is finding that niche of investors with the vision to join our journey. We have succeeded in raising our $30 million series A with these types of investors, whom we’re confident will continue the journey as we scale." 

— Cindy Taff, CEO of SageGeosystems, an energy company focused on developing and deploying advanced geothermal technologies to provide reliable power and sustainable energy storage solutions regardless of geography

"The biggest challenge we've faced has been to bring together massive independent power producers on one side who are investing hundreds of millions of dollars into grid infrastructure with multi- national tech giants on the other that don't have experience working much with energy storage. As a startup with only four employees, gaining credibility with these players was critical. We overcame this hurdle by becoming the preeminent thought leader on storage emissions, through publishing white papers, discussing the issues on podcasts, and (more)."

— Emma Konet, CTO of TierraClimate, a software provider that helps grid-scale batteries reduce carbon emissions

Sage Geosystems will onboard its technology at the Naval Air Station in Corpus Christi. Photo via Naval Air Station Corpus Christi/Facebook

Houston geothermal co. expands DOD partnership with South Texas initiative

seeing green

Expanding on its partnership with the United States Department of Defense's Defense Innovation Unit, Sage Geosystems has been selected to conduct geothermal project development initiatives at Naval Air Station in Corpus Christi.

Along with the Environmental Security Technology Certification Program, Sage will provide its proprietary Geopressured Geothermal Systems technology, will be able to evaluate the potential for geothermal baseload power generation to provide clean and consistent energy at the Naval Air Station base.

“We’re pleased to expand our partnership with the DOD at NAS Corpus Christi to demonstrate the advantages of geothermal technology for military energy independence,” Cindy Taff, CEO of Sage Geosystems, says in a news release.

Sage is also conducting initiatives at Fort Bliss and has completed an analysis at the Ellington Field Joint Reserve Base. The analyses could “pave the way for expanding geothermal energy solutions across additional U.S. military installations,” according to Sage.

The company’s proprietary technology works by leveraging hot dry rock, which is a more abundant geothermal resource compared to traditional hydrothermal formations, and it provides energy resilience for infrastructures. In addition, Sage is building a 3 megawatt commercial EarthStore geothermal energy storage facility in Christine, Texas, which is expected to be completed by December. Sage also announced a partnership with Meta Platforms. With Meta Platforms, Sage will deliver up to 150 megawatt of geothermal power generation east of the Rocky Mountains.

The Naval Air Station Corpus Christi is considered a critical training and operations hub for the U.S. Navy, and the partnership with Sage shows the Navy's commitment to achieving net-zero carbon emissions by 2045. Sage’s technology will be assessed for its ability to create a microgrid, which can reduce reliance on the utility grid and ensure power supply during outages.

“As we advance our Geopressured Geothermal Systems, we see tremendous potential to not only provide carbon-free power, but also strengthen the operational capabilities of U.S. military installations in an increasingly digital and electric world,” Taff adds.

In September, the Air Force awarded Sage a grant of $1.9 million in a first-of-its kind contract to determine whether a power plant using Geopressured Geothermal Systems is able to generate clean energy needed for a base to achieve energy resilience.

Cindy Taff of Sage Geosystems shares her vision for her company and for the future of energy. Photo courtesy of Sage

Profile: Former Shell VP helps create a new way of making clean electricity with Houston company

leading energy

When Cindy Taff was a vice president at the giant oil and gas company Shell in Houston, her middle schooler Brianna would sometimes look over her shoulder as she worked from home.

“Why are you still working in oil and gas?” her daughter asked more than once. “Is there a future in it? Why aren’t you moving into something clean?”

The words weighed on Taff.

“As a parent you want to give direction, and was I giving her the right direction?” she recalled.

At Shell, Taff was in charge of drilling wells and bringing them into production. She worked on oil and natural gas that's called unconventional in the industry, because the oil or natural gas is difficult to get out of the ground — it doesn't naturally gush out like in movies. It's a term often used for oily shale rock. Taff was somewhat unconventional for the industry, too. Her coworkers used to tease her for driving an efficient hybrid.

“You’re not helping oil and gas prices by driving a Prius," they'd say.

______

EDITOR’S NOTE: This is part of an occasional series of personal stories from the energy transition — the change away from a fossil-fuel based world that largely causes climate change.

______

Taff wanted Shell to pursue the energy that comes from the Earth's natural heat — geothermal. Her team looked into it, but Shell never greenlit any of those projects, saying it would take too much time to recoup the investment.

When Brianna went to college, she was passionate about energy too, but she wanted to work on renewables. After her sophomore year, in the summer of 2020, she got an internship at a geothermal company — one that in fact had just been launched by Taff's former colleagues at Shell — Sage Geosystems in Houston.

Now it was Taff looking over her daughter's shoulder and asking question as she worked from home during the pandemic.

And Sage executives were talking to Brianna, too. “We could use your mom here," they said. "Can you get her to come work for us?” Brianna recalled recently.

That's how Cindy Taff left her 36-year career at Shell to become chief operating officer at Sage.

“I didn't understand why Shell wasn't pursuing it,” she said about applying the company's drilling expertise to heat energy. "Then I got this great opportunity to pivot from oil and gas and work with these guys that I have the utmost respect for. And also, I wanted to make my daughter proud, quite frankly.”

Brianna Byrd, now 24, is the operations engineer and spokesperson at the company. She's glad her mother, now CEO, left oil and gas.

“Of course I’m biased, she’s my mom, but I don’t think Sage would be where it is without her,” she said.

The United States is a world leader in electricity made from geothermal energy, but this kind of electricity still accounts for less than half a percent of the nation’s total large-scale generation, according to the U.S. Energy Information Administration. In 2023, most geothermal electricity came from California, Nevada, Utah, Hawaii, Oregon, Idaho and New Mexico, where there are reservoirs of steam, or very hot water, close to the surface.

The Energy Department estimates this next generation of geothermal projects, like what Sage is doing, could provide some 90 gigawatts by 2050 — enough to power 65 million homes or more. That hinges on private investment, and on companies like Sage introducing this form of energy to regions where, until now, it’s been thought to be impossible.

How it works

Sage has two main technologies: The first makes electricity out of heat. The company drills wells and fractures hot, dry rock. Then electric pumps push water into those fractures, heating it up, and the hot water gets jettisoned to the surface where it spins a turbine.

But a funny thing happened during testing in Starr County, Texas. In late 2021, the team realized much of their technology could also be used to store energy.

If that works, it could be a big deal. Currently, to store energy at large scale, the United States is adding batteries, mostly lithium-ion type, to solar and wind projects, so they can charge up and send electricity back to the electric grid when the sun is not shining or the wind is not blowing. These batteries typically supply four hours maximum power.

Sage envisions some of its technology placed at solar and wind farms, too. When electricity demand is low, they'll use extra energy from a solar or wind farm to run electric pumps, pumping water into the underground fractures, leaving it there until demand for electricity increases — storing the energy beneath the Earth's surface for hours, days or even weeks.

It's a novel way to use the technology, said Silviu Livescu, lead author on a report looking at the future of geothermal in Texas. Livescu knows Taff and has followed the company's progress.

“It’s the right moment for companies like Sage with a purpose, with a mission and with the technology to show that geothermal indeed is the energy source we need to address climate change,” said Livescu, who co-founded a different geothermal startup in Austin, Texas.

These days, Taff is often out in front, talking with politicians and policymakers about the potential of geothermal. She attended the United Nations COP28 climate talks last year to share her vision for this kind of energy.

Sage has raised $30 million so far and is growing.

It's building a small (3-megawatt), geothermal energy storage system at San Miguel Electric Cooperative, Inc., south of San Antonio this year. It's working with U.S. military facilities in Texas that see geothermal as a way to power their bases securely. Sage recently announced partnerships for heating communities in Bucharest, Romania; clean electricity from geothermal for Meta's data centers, and energy storage and geothermal projects in California.

The company is final-testing a proprietary turbine to more efficiently convert heat to electricity.

Because of her oil and gas background, Taff said she knows geothermal will only be adopted widely if the cost comes down. The mantra at Sage is: It's going to be clean and it's going to be cheap. She's excited to be working in a field she feels is on the cusp of playing a big role in cleaning and stabilizing the electrical grid.

“I’ve never looked back,” she said. “I love what I’m doing and I think it’s going to be transformative.”

Houston startup Sage Geosystems has announced a new $1.9 million deal with the Air Force. Photo via sagegeosystems.com

US Air Force awards Houston geothermal co. $1.9M grant project

big deal

The Department of the Air Force awarded Houston geothermal company Sage Geosystems Inc. a grant of $1.9 million in a first-of-its kind contract to determine whether a power plant using Geopressured Geothermal Systems is able to generate clean energy “needed for a base to achieve energy resilience,” according to a news release. The Sage facility will be the first GGS facility in the world to generate electricity, and the system will be constructed at an off-site test well in Starr County, Texas.

”We are excited to partner with the U.S. Air Force on this geothermal demonstration project,” CEO of Sage Geosystems Cindy Taff says in a news release. “Next generation geothermal technologies, like Sage Geosystems’ GGS, will be critical in providing energy resiliency at U.S. military installations.”

In addition to the grant, the company will match the grant with an additional $1.9 million for the demonstration project. The collaboration with Sage is one of three geothermal pilot projects the DAF has initiated in regards to next-generation geothermal technologies in 2024.

“We feel this is the launch pad of helping not only the DoD but many other applications throughout global markets,” 147th Civil Engineer Squadron Commander Lt Col Christian Campbell says in the release.

According to the DAF, the possibility of a full-scale project at Ellington Field Joint Air Reserve Base in Houston could usher in a new era of clean power producing plants to help meet the requirements for bases.

“This initial contract is a step forward in the Air Force’s push for energy resilience,” Kirk Phillips, director of the Air Force Office of Energy Assurance, adds in the release. “This project will improve Ellington Field’s ability to maintain operations during electrical grid outages and be completely self-sufficient for their energy needs.”

The GGS process works by repurposing fracking technology to extract thermal energy from below the Earth’s surface.GGS also demonstrates the opportunity for the civilian sector by surpassing the intermittency challenges for solar and wind energy generation. GSS can also work towards minimizing land use, which enables the technology to be used in urban areas without relying on transmission line build outs that can be expensive.

“This project, and the future Department of the Air Force projects that it paves the way for, will help to assure that our national security needs are met by our installations during critical emergencies,” Phillips continues.

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Houston researchers earn $3.3M in DOE funding to develop safer underground power line installation

going under

Researchers from the University of Houston — along with a Hawaiian company — have received $3.3 million in funding to explore artificial intelligence-backed subsurface sensing system for safe and efficient underground power line installation.

Houston's power lines are above ground, but studies show underground power is more reliable. Installing underground power lines is costly and disruptive, but the U.S. Department of Energy, in an effort to find a solution, has put $34 million into its new GOPHURRS program, which stands for Grid Overhaul with Proactive, High-speed Undergrounding for Reliability, Resilience, and Security. The funding has been distributed across 12 projects in 11 states.

“Modernizing our nation’s power grid is essential to building a clean energy future that lowers energy costs for working Americans and strengthens our national security,” U.S. Secretary of Energy Jennifer M. Granholm says in a DOE press release.

UH and Hawaii-based Oceanit are behind one of the funded projects, entitled “Artificial Intelligence and Unmanned Aerial Vehicle Real-Time Advanced Look-Ahead Subsurface Sensor.”

The researchers are looking a developing a subsurface sensing system for underground power line installation, potentially using machine learning, electromagnetic resistivity well logging, and drone technology to predict and sense obstacles to installation.

Jiefu Chen, associate professor of electrical and computer engineering at UH, is a key collaborator on the project, focused on electromagnetic antennas installed on UAV and HDD drilling string. He's working with Yueqin Huang, assistant professor of information science technology, who leads the geophysical signal processing and Xuqing Wu, associate professor of computer information systems, responsible for integrating machine learning.

“Advanced subsurface sensing and characterization technologies are essential for the undergrounding of power lines,” says Chen in the release. “This initiative can enhance the grid's resilience against natural hazards such as wildfires and hurricanes.”

“If proven successful, our proposed look-ahead subsurface sensing system could significantly reduce the costs of horizontal directional drilling for installing underground utilities,” Chen continues. “Promoting HDD offers environmental advantages over traditional trenching methods and enhances the power grid’s resilience.”

Aramco partners to demonstrate compact carbon capture technology for gas turbines

dream team

Integrated energy and chemicals company Aramco has signed a collaboration agreement with Carbon Clean and SAMSUNG E&A in an effort to showcase new carbon capture technology.

The technology demonstration will be used to deploy Carbon Clean’s novel CycloneCC technology to capture CO2 from natural gas turbine exhaust streams containing approximately 4 percent CO2, according to Aramco.

Carbon Clean, which U.S. headquarters are located in Houston at the Ion, boasts technology that has captured nearly two million tons of carbon dioxide at almost 50 sites around the world. Aramco’s U.S. headquarters is also in Houston.

“The potential for CycloneCC in the US and Houston area is huge,” Aniruddha Sharma, chair and CEO of Carbon Clean, previously shared with EnergyCapital. “It is optimised for low to medium scale industrial emitters and recent Rice University research on the US Gulf Coast, for example, found that it is well suited to 73 percent of Gulf Coast emitters.”

The modular CycloneCC unit has a 50 percent smaller footprint compared to conventional carbon capture processes. The CycloneCC technology is estimated to reduce the total installed cost of carbon capture systems by up to 50 percent compared to conventional systems if successful. The goal is to also maintain process efficiency even at low CO2 concentrations. CycloneCC’s performance is achieved through two process intensification technologies, rotating packed beds (RPBs) and Carbon Clean’s proprietary APBS-CDRMax solvent.

“Its compact, modular design should be easily integrated with gas turbines, delivering high performance carbon capture in an industrial setting where space is typically limited,” Sharma says in a news release.

The engineering, procurement and construction of the plant will be done by SAMSUNG E&A .The unit will be installed on the sales gas compressor turbine exhaust gas stack,which can provide performance data under real-world conditions.

“Aramco and Samsung Ventures are investors in Carbon Clean, so we’re proud to deepen our relationship through this partnership,” Sharma adds. “This first-of-a-kind deployment capturing very low concentrations of CO2 is a key milestone in scaling up and commercializing CycloneCC.”

In September, Carbon Clean also announced a deal with PETRONAS CCS Solution to collaborate and evaluate Carbon Clean’s carbon capture and storage technology with Carbon Clean's CycloneCC tech. Last year, Abu Dhabi National Oil Co. (ADNOC) selected Carbon Clean for a carbon capture project in Abu Dhabi.