Mike Eros - Chief Geoscientist of Sage Geosystems

In this episode, we’re diving into the world of subsurface energy storage and geothermal power with Mike Eros, Chief Geoscientist at Sage Geosystems, where he’s pioneering geo-pressured geothermal and long-duration energy storage solutions. A former ExxonMobil subsurface expert, he’s now helping reshape how we tap into and store Earth’s heat.We explore how Mike transitioned from oil and gas into geothermal, the potential of geo-pressured systems for grid-scale power and storage, and Sage Geosystems’ groundbreaking projects reshaping the future of energy.Episode At-a-Glance* Storage + Geothermal: Sage merges long-duration pressure storage with geothermal heat extraction — delivering baseload + peaking power from the same well.* From O&G to Geo: Subsurface and drilling skills transition directly into geothermal; the biggest bottleneck is industry awareness, not ability.* EarthStore Pilot: First 3 MW project in Texas test results showing 70–75% storage efficiency with <2% fluid loss — built using off-the-shelf drilling tools.* DoD + Meta: Early customers want resilience (military bases) and 24/7 clean power (data centers).* Ormat Partnership: Taps into existing interconnections and Ormat’s equipment procuring capabilities — potentially reducing geothermal timelines from years to months.* Superhot Roadmap: Drill to ~16,000 ft, then frack deep to access 300°C rock for 10× power density using mostly standard oil & gas gear.* The Big Blockers: Organic-Rankine Cycle (ORC) turbine and broader equipment delays, interconnection queues, and lack of drilled pilots — not geology.⏱️ Timestamps (Notes below)[1:04] What got Mike into Geothermal? What was his career?[6:14] How do Sage’s Pressured Geothermal Systems work?[16:59] Why do we push the working fluid lung-like “huff-n-puff” operations in fractures?[21:06] What are the variables affecting the economics on your projects and the efficiencies on your storage projects? How can we make geothermal scale faster?[29:55] How does your team measure success? What are the longer term goals?[33:57] How is your team exploring using super critical CO2 as a working fluid?[36:15] What does it look like to build out a Sage site from ideation to creation?[40:59] How is your team engaging with different partners to get things done? [43:07] What are the risks and challenges your team is facing?[45:58] How does financing these different projects look?[49:54] How does your team work with different locales to help integrate projects with the community? What about other regulatory frameworks and environmental risks your team has to handle?[59:31] How are the steps back in supporting certain renewables like wind and solar impacting your team?[1:04:49] Lessons from working with San Miguel Electric Cooperative and ERCOT[1:11:07] How is your team approaching permitting in regards to your work in Altascosa County?[1:13:50] How has your team been approaching the grid interconnection process?[1:15:22] Digging in on the project with the US Air Force in Starr County.[1:19:07] How is your team developing and navigating partnerships with other military branches and the broader US military?[1:22:31] Sage and Meta’s partnership and how the team is approaching it.[1:25:59] Partnership with Ormat in the west.[1:29:29] Where do you see this partnership with Ormat going?[1:31:50] How have technological advancements in energy and drilling contributed to geothermal today?[1:40:08] How can we get communities and the government more excited about geothermal? What can they do to help?[1:45:18] What’s coming up for Sage?[1:48:23] If you had a magic wand, what problem in geothermal would you solve today?Additional Notes* Regarding 10 to 20% dilation - As an additional note, the larger the volume put in the ground compared to the percent that is brought out/smaller volumes allows the system to stay above fracture opening pressure. This maintains sufficient presssure in the fracture to keep the system open without proppant.* Regarding the mention of $0.065/kWh - Mike misspoke on the 10-12 cents. He meant that the costs would fall to the lower side with scale with a target of 6 to 7 cents per kWh. Additionally, for energy storage, the team is targetting Long-duration CAPEX of $2.25M/MW.🔬 Sage’s Tech: What Makes “Geo-Pressured Geothermal” Unique?If you’re new to Sage, their system is: part geothermal, part inverted pumped hydro.Instead of just drilling into hot dry rock and circulating water, they:* Drill mostly vertical wells, with a short deviation.* Create a lung-shaped fracture network beneath the surface.* Cycle fluid in a “huff-and-puff” pattern—injecting to build pressure, then releasing it to run a surface turbine. Where it fits in:* 8-12 hour duration long-term storage* Ideal for solar-heavy regions like Texas & California, as well as Australia* Cheaper + higher energy density than lithium-ion beyond 4 hour discharge durationsSo far, this has led to:...