Geothermal at super-critical depths

[Sparty]

1. Geothermal power at supercritical depths:
- EPFL's Laboratory of Experimental Rock Mechanics (LEMR) has made a breakthrough.
- They've shown that rock at supercritical depths (around 10 km or 6.2 miles) can still be fractured to allow water flow.

2. Supercritical water:
- At these depths, water becomes "supercritical," behaving like a hybrid of liquid and gas.
- This supercritical water can potentially generate 10 times more power than conventional geothermal plants.

3. Challenges:
- Drilling to such depths (beyond 12 km or 7.5 miles) is currently beyond our engineering capabilities.
- The rock at these depths becomes semi-plastic and gooey, which was thought to prevent fracturing.

4. Potential applications:
- If deep drilling becomes feasible, geothermal plants could be set up almost anywhere.
- Abandoned coal-fired power plant sites could be repurposed for geothermal energy production.

5. Research breakthrough:
- An EPFL team led by Gabriel Meyer used advanced techniques to study rock behavior at these depths.
- They employed a gas-based triaxial apparatus, high-resolution synchrotron 3D imagery, and finite element modeling.
- Their findings suggest that fracturing rock at supercritical depths is possible, contrary to previous assumptions.

This research opens up new possibilities for geothermal energy. If we can overcome the engineering challenges of deep drilling, it could lead to a significant increase in clean, renewable energy production worldwide. The ability to repurpose existing power plant infrastructure for geothermal use is particularly promising from both economic and environmental perspectives.

More:

https://techxplore.com/news/2024-06-...le-energy.html

https://geothermal-energy-journal.sp...17-024-00288-4

[Sparty]

Currently, the deepest human-made hole in the Earth's crust is the Kola Superdeep Borehole, located in Russia. Here are some key points about current drilling capabilities:

Kola Superdeep Borehole:

Depth: Approximately 12.2 km (7.6 miles)
Drilled between 1970 and 1989
Primary purpose was scientific research, not resource extraction


Oil and gas industry:

Typical oil wells: 1-3 km (0.6-1.9 miles) deep
Deep water offshore wells: Can exceed 10 km (6.2 miles) when measuring from sea level


Geothermal energy:

Most current geothermal wells: 1-3 km (0.6-1.9 miles) deep
Some advanced projects aim for 4-5 km (2.5-3.1 miles)


Recent notable projects:

Iceland Deep Drilling Project (IDDP): Aimed to drill to 5 km (3.1 miles) depth
San Andreas Fault Observatory at Depth (SAFOD): Reached about 3 km (1.9 miles)


Challenges of deep drilling:

Extreme temperatures: Can exceed 300°C (572°F) at depths beyond 10 km
High pressure: Increases with depth, making drilling more difficult
Equipment limitations: Standard drilling equipment isn't designed for such extreme conditions
Cost: Increases exponentially with depth


Emerging technologies:

Some companies are developing new drilling technologies aimed at reaching greater depths more efficiently

These include advanced drill bits, better cooling systems, more durable materials and high power millimeter wave technology.

It's worth noting that while the Kola Superdeep Borehole reached an impressive depth, it was an extreme scientific endeavor and not representative of typical drilling operations. Most practical drilling for resource extraction or energy production occurs at much shallower depths.

The research you mentioned about fracturing rock at supercritical depths (around 10 km) is exciting because it suggests that if we can overcome the engineering challenges of drilling that deep, we could access an enormous potential energy source. However, reaching those depths consistently and economically remains a significant challenge with current technology.

[Sparty]

Quaise Energy, a startup spun out of MIT, is developing a potentially revolutionary drilling technology: Quaise, Inc was founded in 2018 to develop a millimeter-wave drilling system for converting existing power stations to use superdeep geothermal energy.

"Quaise says its hybrid drilling rig – using a traditional rotary bit to get through the easy stuff and a gyrotron-powered energy beam to melt, fracture and vaporize the tough stuff – will take just 100 days to deliver you a hole 20 km (12.4 miles) deep. Three and a bit months gets you a long-term green energy supply, in a stable bore hole lined with glassy melted rock, wherever you want it."

Core technology:

Uses high-power millimeter wave energy (similar to microwaves, but more focused) to vaporize rock

Based on gyrotron technology developed for nuclear fusion research


Drilling method:

Starts with conventional rotary drilling for the initial depth
Switches to millimeter wave technology for deeper, hotter layers
Aims to reach depths of 10-20 km (6.2-12.4 miles)


Advantages:

Can potentially drill much deeper than conventional methods
Doesn't rely on mechanical components that can fail under extreme heat and pressure
Might be faster and more cost-effective for very deep drilling


Current status (as of my last update in April 2024):

Still in development and testing phase
Has received significant funding and attention in the geothermal industry
Planning field tests to demonstrate the technology at scale


Potential impact:

If successful, could unlock access to supercritical geothermal resources
Might enable geothermal energy production in many more locations globally


Challenges:

Scaling the technology from lab tests to field operations
Managing the vaporized rock and creating stable boreholes
Integrating with existing geothermal power generation systems

Quaise's technology is particularly exciting because it directly addresses the drilling depth limitations we discussed earlier. If successful, it could be a game-changer for geothermal energy production, potentially allowing us to tap into the supercritical resources that the EPFL research suggests are accessible.

However, it's important to note that while promising, this technology is still in development and has yet to be proven at the scale and depths required for commercial geothermal energy production. https://newatlas.com/energy/quaise-d...ing-questions/

[Sparty]

Would it be cheaper and easier just to access geothermal heat reserves closer to the surface?

Australia the lucky energy rich country has several very large geothermal resources that are shallow (in relative terms) and could provide access to power from natures nuclear power heat production.... see www.hotrockenergy.com