Open Circuit Presents: The Green Blueprint — "Sage Geosystems’ Bet on Underground Energy Storage"

Podcast: Open Circuit (Crosspost of “The Green Blueprint”)
Host: Laura Pierpoint
Guest: Cindy Taft, CEO, Sage Geosystems
Date: February 20, 2026

Episode Overview

This episode dives into Sage Geosystems’ innovative approach to long-duration energy storage: using underground “pressure geothermal” storage. Host Laura Pierpoint interviews CEO Cindy Taft about her transition from oil and gas to clean energy, the technical and business breakthroughs behind Sage’s “pumped hydro flipped upside down,” the construction of their first commercial facility, grid interconnection hurdles, and how oil and gas expertise is fueling geothermal’s rise. The conversation covers how these technologies could be transformative for grid-scale renewable energy, blending geothermal and storage, and the critical path to commercialization.

Key Discussion Points & Insights

1. From Oil & Gas to Geothermal (07:03 - 07:33)

• Cindy’s Transition: Cindy Taft previously led unconventional wells at Shell. She was recruited to Sage Geosystems by partners who believed oil and gas expertise could unlock new geothermal approaches.
• Quote:

  "What a great opportunity to pivot from oil and gas and use those skills to do geothermal power generation."
  — Cindy Taft (07:19)

2. The “Upside Down” Pumped Hydro Storage Model (01:50 - 03:51, 18:50 - 20:52)

• Sage innovates by combining fracking with energy storage: instead of pumping water up a mountain (traditional pumped hydro), they pump it deep underground and use fractured rock for pressurized storage.
• Pressure Geothermal: Their method, “pressure geothermal,” leverages both the earth’s heat and pressure—enabling both storage and geothermal power generation.
• Quote:

  “We're pioneering what we call pressure geothermal, which leverages both the heat and the pressure of the earth, which allows us to do energy storage ... and also allows us to do power generation from geothermal.”
  — Cindy Taft (02:58)

• Unique Advantage: Their wells are deeper (8,000–12,000 feet) than any pumped hydro, creating higher energy density.
• How It Works: Water is injected into a deep fracture, held open under pressure (like a lung), and when released, the closing fracture drives water up through a Pelton turbine to generate electricity.
• Quote:

  “The deeper you go, the higher that energy density is going to be because of that pressure energy.”
  — Cindy Taft (20:52)

3. Long-Duration Storage: Solving Renewables’ Limits (02:58 - 09:38)

• Need for Long Discharge: Lithium-ion batteries handle only short storage; solar+storage projects replacing coal plants require much longer discharge (up to 16+ hours).
• Sage vs Batteries: Sage’s solution can offer the critical long-duration output required to “turn solar into 24-hour power generation.”
• Quote:

  “If you're trying to turn solar into 24 hour, you need a 16 hour discharge duration basically ... ours is made really for that longer duration.”
  — Cindy Taft (08:38)

4. Fast-Track Construction, Slow Grid Interconnection (11:32 - 15:04)

• Construction Speed: Sage built and commissioned its first commercial facility in just 13 months.
  • Most pre-construction time was spent on engineering, equipment procurement, and partnering with EPC and turbine vendors.
  • Field work (site prep, drilling, fracking, facility build) took ~7 months.
  • Quote:

    "We were actually able to build and commission that facility in 13 months ... Now we're just waiting on the grid interconnection to actually operate that facility."
    — Cindy Taft (11:52)

• Grid Interconnection: Despite speedy construction, Sage faces a long wait for grid interconnection (over a year), due to a slow, linear process that creates bottlenecks.
  • Problem: Feasibility studies snowball into year-long waits, and too many “maybe” projects clog the queue.
  • Quote:

    “The queue gets very long and then projects will drop out, which will speed up the queue eventually. But it's still a huge challenge because that queue is ... falsely too long because there are technologies ... that may never be built.”
    — Cindy Taft (15:04)

5. Engineering Approach & Lessons Learned (22:45 - 23:32)

• Thorough Development: Sage invested heavily in field and engineering studies before building, to “de-risk” construction and ensure reliability.
  • 6–9 months on design, 7 months construction.
  • Learning Curve: The pre-engineering phase for future facilities should be shorter thanks to these learnings.
• Supply Chain: Securing non-standard Pelton turbines (5,000 psi) was crucial for adaptation to underground/high-pressure environments.

6. Technical Deep Dive: Pressure, Duration, and Flexibility (20:52 - 22:45)

• Storage Duration: By targeting “low permeability rock” (≤ 50 millidarcys), water and pressure can be stored underground for weeks or even months—enabling potential seasonal storage.
• Losses: Some water loss is possible depending on formation, but it can be replenished, and certain formations show almost “no leak off.”

7. Oil & Gas Meets Clean Tech—Industry Integration (30:01 - 33:38)

• Industry Convergence: Geothermal is unique in integrating oil/gas and clean tech—drilling, engineering, and project management skills transfer seamlessly.
• Scaling Potential: Oil/gas drilling experience supports massive scale-up potential for geothermal—skills and service backing already in place.
• Quote:

  “The overlay between the two industries is just so spot on ... The infrastructure is there, it's already primed to scale. Geothermal.”
  — Cindy Taft (32:23)

• Bipartisan Appeal: Geothermal receives broad political and industry support thanks to this inclusive skill base.

8. Tech & Business Model Breakthroughs (34:23 - 35:38)

• Horizontal Drilling & Fracking: Advances from the shale oil boom (cheaper horizontal drilling, multi-stage fracking) are the technological foundation for next-generation geothermal.
• Missed Renaissance: Geothermal’s evolution was slowed by the shale boom in the ‘90s but is now benefiting from those advances.
• Quote:

  “The oil and gas industry impacted next generation geothermal way back then, but again it's what's impacting it now in a more positive way.”
  — Cindy Taft (35:17)

9. Strategic Partnership—Sage & Ormat (36:00 - 40:54)

• Why Partner with Ormat? Ormat, global leader in conventional geothermal, wants to diversify into next-gen “engineered” systems like Sage’s (hot, dry rock vs. the “unicorn geology” of conventional).
• Collaboration: Ormat brings scale and deep resources; Sage brings tech and niche know-how.
• Quote:

  “The relationship is a good one. ... They have geologists and subsurface people and drilling engineers ... So I think the relationship is a good one. It's something that is beneficial to Sage.”
  — Cindy Taft (39:24)

• Outlook: The opportunity (“the size of the pie”) is so large, there’s plenty of room for multiple players and growth.

10. The $100 Million Question (41:48 - 42:42)

• If Given $100 Million: Cindy’s answer is clear—she would immediately expedite the field deployment of additional commercial-scale geothermal/storage facilities.
• Quote:

  “We would do it on an expedited timeline because not only does the country need this power, but the world needs the power.” — Cindy Taft (41:58)

Standout Quotes

• "It's like pumped storage, but upside down ... this is a big deal."
  — Cindy Taft (02:29)
• "We are on the learning curve, is where wind and solar were like 10 or 15 years ago."
  — Cindy Taft (04:47)
• “Geothermal is everywhere around the world under our feet.”
  — Cindy Taft (41:58)

Notable Timestamps

• 01:36–03:51: Establishing Sage’s key concept and the challenges/opportunity of geothermal-plus-storage.
• 07:03–08:18: Cindy’s recruitment to Sage, launch of their 2023 Texas pilot.
• 11:32–15:04: Construction timeline and the grid interconnection challenge.
• 18:50–22:45: Deep technical dive on the mechanics, efficiency, and flexibility of pressure geothermal storage.
• 30:01–33:38: Oil & gas sector skills fueling geothermal, industry convergence.
• 36:00–40:54: Partnership with Ormat—strategy, challenges, and perspectives.

Tone & Style

The episode maintains an enthusiastic, solutions-oriented tone. Laura Pierpoint’s approach is inquisitive and insider-savvy; Cindy Taft is pragmatic, technically detailed, and optimistic about geothermal’s future and its integration with both oil and gas and clean energy sectors.

Conclusion

Sage Geosystems’ approach signals a new era for geothermal—tapping oil and gas knowhow, creating mechanical energy storage beneath our feet, and offering renewables the long-duration storage needed for deep grid decarbonization. Expedited construction is possible, but grid interconnection remains a major bottleneck. With new partnerships like Ormat, and industry integration, geothermal stands poised for breakout growth.