Dec 17, 2025 · 38m · green-blueprint
Sage Geosystems' bet on underground energy storage
0:00 / 0:00
gold bands on the timeline = statements, start to end. Hover to read, click to jump. CC turns on captions
On The Green Blueprint, Sage Geosystems CEO Cindy Taff explains how the company repurposed oilfield drilling and hydraulic fracturing technologies into subsurface pressure geothermal storage and baseload clean power. Taff details the mechanical engineering behind their system, pilot demonstrations with rural electric cooperatives, and strategic industry partnerships scaling next-generation geothermal across global grids.
How this conversation actually went
Every chapter scored 0–10 on four independent dynamics. Hover any point for the reasoning behind the score. How this is scored →
The hosts as informed peer 4.9 Guest teaching 4.2 Guest disagreement 0.2 The hosts pushing back 1.0
speaking balance: gold is the hosts, purple is the guest (3 minute bins)
Sharpest disagreement ▶ 35:09 Taff rejects framing of partner conflict with Ormat
Taff deflects the host's suggestion that Sage must fight for territory against Ormat, asserting that the market pie is sufficiently large for all players.
Hardest push from the hosts ▶ 34:56 Pierpoint presses on startup power dynamicsPierpoint directly asks whether Sage has to push back against overbearing corporate partners to protect its internal value.
Biggest teaching moment ▶ 30:45 Taff explains unicorn geology versus hot dry rockTaff breaks down the strict three-legged stool requirements of conventional geothermal and why next-generation hot dry rock enables widespread geographical expansion.
The host holds their own ▶ 14:32 Pierpoint probes the physics of inverted pumped hydroPierpoint demonstrates technical fluency by questioning how mechanical pressure substitutes for gravitational potential energy in subsurface storage systems.
the scores for every segment, with the reasoning behind each
| Chapter | Topic | The hosts as informed peer | Guest teaching | Guest disagreement | The hosts pushing back | Why |
|---|---|---|---|---|---|---|
| Cindy Taff's Background and the San Miguel Electric Co-op Project | 4 | 3 | 0 | 0 | Pierpoint provides context on the San Miguel Electric Co-op coal-to-clean transition. Taff explains why long-duration 16-hour storage is necessary to turn intermittent solar into firm baseload capacity. | |
| Structuring the SMECI Facility and Long-Term Solar Expansion | 5 | 4 | 0 | 1 | Pierpoint questions how Sage managed a 12-month commercial build. Taff details the 5,000 PSI re-engineered Pelton turbine and clarifies that field construction took only seven months despite interconnection delays. | |
| Grid Interconnection Bottlenecks and Reform | 5 | 4 | 1 | 1 | Pierpoint asks about the timing of interconnection requests and highlights permitting reform. Taff contrasts the electric grid's linear feasibility study process with parallel operations common in oil and gas. | |
| Technical Mechanics of Subsurface Pressure Storage | 6 | 6 | 0 | 1 | Pierpoint asks a technical question regarding how pressure gradients replace gravitational potential energy when flipping pumped hydro upside down. Taff breaks down overburden rock weight, cycling mechanics, and the lung analogy. | |
| Subsurface Geology, Rock Permeability, and Storage Duration | 6 | 5 | 0 | 1 | Pierpoint explores seasonal storage potential and pre-construction engineering de-risking. Taff explains subsurface geology requirements, millidarcy permeability ratings, and the pre-engineering timeline. | |
| Mid-Show Break and Preview | 5 | 4 | 0 | 0 | Pierpoint brings up the bipartisan appeal of oil and gas technology transfers to clean energy. Taff notes the massive scale divergence between the two industries and emphasizes workforce adaptability over sectors like nuclear. | |
| Technological Evolution from the Shale Revolution to Geothermal | 6 | 5 | 0 | 1 | Pierpoint asks whether modern geothermal viability is due to a single breakthrough or incremental progress. Taff explains how horizontal drilling and multi-stage fracking techniques from the shale revolution unlocked geothermal scaling. | |
| Next-Generation Geothermal and the Ormat Partnership | 5 | 6 | 0 | 1 | Pierpoint inquires about partnering with incumbent giant Ormat. Taff educates on the differences between conventional hydrothermal geology and next-generation engineered hot dry rock reservoirs. | |
| Collaborating with Industry Giants and Market Opportunity | 5 | 3 | 1 | 4 | Pierpoint presses Taff on startup power dynamics, asking if Sage feels the need to fight for territory against an overbearing partner. Taff gently dismisses the conflict framing, arguing the market opportunity is large enough for everyone. | |
| Capital Allocation Vision and Podcast Conclusion | 2 | 2 | 0 | 0 | Pierpoint closes with a hypothetical question on allocating 100 million dollars of capital. Taff reaffirms Sage's priority to accelerate commercial power generation deployment before closing out. |
Statements from this episode (16)
Pumped hydro accounts for 90% of global energy storage capacity
“Most of the energy storage in the world, about 90% of all energy storage globally, is pumped hydro, which requires a mountain, a ton of water, and usually a whole lot of permitting.”
San Miguel Electric Cooperative secured a $1.4B USDA grant for renewables
“Historically, it's operated a coal plant, but in twenty-twenty-four, SMECI got a one-point-four-billion-dollar grant from the U.S. Department of Agriculture to transition to solar and storage.”
Turning solar into 24-hour power requires a 16-hour storage discharge duration
“If you're trying to turn solar into 24 hour, you need a 16 hour discharge duration, basically to produce power, you know, between the time the sun goes down to the time the sun comes back up.”
Sage's subsurface storage is more cost-effective than lithium-ion batteries
“You're using four batteries to achieve that 16 hour duration, whereas ours, it's made really for that longer duration, and so it's going to be more cost effective than the batteries.”
Sage Geosystems built and commissioned its commercial storage facility in 13 months
“We were actually able to build and commission that facility in 13 months. That's from funding to actually being ready to store power.”
Sage re-engineered commercial Pelton turbines to withstand 5,000 PSI
“The Pelton turbines that are out there in the industry for pump storage hydropower are not rated to the same pressure as our Pelton turbine, so our Pelton turbine's rated to 5000 PSI, and that's because, again, we are deeper than the tallest pumped hydro, so w…”
Sage's grid interconnection feasibility study took 11 months despite shorter estimates
“The feasibility study, in the beginning, we were said, told it, it'll take six weeks, And then we immediately put our application in, and then we were told it'll take six months, and then it ended up taking, like, 10 or 11 months.”
Grid interconnection queues are artificially inflated by unfunded, speculative projects
“Because the process is so long, different Projects will be put into the queue, even though they may or may not be funded, even though they may or may not, you know, know that they're going to be going forward, and so the queue gets very long, and then projects…”
Sage's systems operate deeper than pumped hydro, yielding higher energy density
“So, we actually are deeper than the tallest pumped hydro, which is about 3000 feet. Our depths are eight to 12,000 feet. So we have actually a higher energy density, so the deeper you go, the higher that energy density is going to be because of that pressure e…”
Sage Geosystems targets rock formations with permeability under 50 millidarcies
“So there, the permeability measure is millidarces, so we want 50 millidarces or less.”
Sage's subsurface pressure technology can store energy for weeks or months
“So yes, we can literally store the water for weeks, if not months you know, and we would just monitor the pressure depending on the formation permeability. We may have to have water added occasionally to keep the pressure up, but in some formations, like I sai…”
Pierpoint: Many climate tech startups cut corners on pre-construction engineering
“When it comes to doing engineering studies and development work and everything that happens before you construct, a lot of folks cut corners and they don't want to spend a lot of time doing a huge amount of de-risking because there's a lot of binary risk in th…”
US geothermal drills roughly 50 wells annually compared to oil's 30,000
“The geothermal, geothermal industry, which drills, you know, anywhere from, say, 30 to 50 wells a year, and the, and this is in the U.S., and the oil and gas industry, which drills, you know, 20 to 30,000 wells a year, did not get together.”
The oil and gas industry is equipped to scale geothermal energy
“The oil and gas industry is primed. The infrastructure is there. It's already primed to scale geothermal once the industry, again, is ready to scale. We don't have to wait on new skill sets being built”
Horizontal drilling and fracking advances enabled next-generation geothermal cost reductions
“Those technology developments, the horizontal drilling, driving the cost down of horizontal drilling, as well as multi-stage fracking in a well is exactly what The next generation geothermal needed in order to drive down cost and in order to make it a an affor…”