The top of the magma chamber starts ~5-17 km from the surface with another magma chamber ~20-50 km from the surface. Heat starts and goes well above that of course but if your goal is to meaningfully hook into and extract the heat of the chamber itself it's quite deep. Put from another perspective: if a significant amount of the energy of the chamber were imminently near the surface it would already fizzle itself out over thousands of years without the need of digging short holes to do it in a few.

Geothermal in Yellowstone is no better or more useful than geothermal at many other less important places. It isn't even the place with the most surface level geothermal energy in the first place. Overall geothermal technology advancement makes a lot of sense but starting said advancement via sandbagging for an outcome 1000 years after developing one of the best national parks to do so does not make sense.

Regardless of all of that, there are significantly more than the two possibilities of either starting drilling today or having catastrophe in an eruption.

The reason why I noted a thousand year period is because Yellowstone is said to have a lot more energy than we can use right now.

Regarding the investment, if a 5 km well is dug, I don't expect it to exhaust its energy without a significant payback.

AFAIU the "last mile" (or last 5--17 km) transfer largely occurs through ground-water migration. Yellowstone combines extensive geothermal energy with ample surface water flow (e.g., Lake Yellowstone, which is itself a major geothermal zone). I'm really well beyond my depth here, though looking up soem background:

Geological diagram of Old Faithful: <https://public-media.smithsonianmag.com/filer/bd/06/bd0603df...>

From this Smithsonian article: <https://www.smithsonianmag.com/smart-news/seeing-beneath-old...>

"Old Faithful's Geological Heart Revealed": <https://www.sciencedaily.com/releases/2017/10/171005190243.h...>

Mostly addresses seismic activity, though there's some discussion of inferred structures from that. Based on the journal article by Sin-Mei Wu, Kevin M. Ward, Jamie Farrell, Fan-Chi Lin, Marianne Karplus, Robert B. Smith. "Anatomy of Old Faithful from subsurface seismic imaging of the Yellowstone Upper Geyser Basin". Geophysical Research Letters, 2017; DOI: 10.1002/2017GL075255 <http://dx.doi.org/10.1002/2017GL075255>

(The Smithsonian piece is based on the same article.)

Exactly. I am not convinced that drilling 5 km is necessary at Yellowstone. I suspect the energy is ripe for the taking much closer to the surface due to this water migration.

AFAIU yes, absolutely.

Yellowstone has accessible thermal gradients. Even if a remote approach is made, say, outside the National Park boundaries and intended to minimise surface impacts, necessary drilling should be minimal, and a small number of wells should provide far more energy return than a large number of deep boreholes.

That said, I'm, ahem, well out of my depth here ;-)

Efficiencies of scale from multiple drilling operations likely pale in comparison to the costs of each well. Keep in mind that some factors, such as well casings, drilling mud, drill bits, labour, and support costs remain high on a per-well basis. A 10% savings evaporates quickly if 100 wells are required to match the energy return of 1 or 10. Well depth and diameter are major determinants of drilling costs in both petroleum and geothermal operations.

The ability to achieve a high, long-term return on relatively shallow drilling operations probably trumps any learning-curve efficiency improvements in drilling itself. Sites such as Yellowstone (based on some former research I'd made) contribute significantly to US baseload electrical generation, should the US choose to exploit them.

It's also worth noting that there already is considerable expertise in drilling generally, with over 160 years of experience over millions of individual wells, and that the efficiency / improvement curve is likely fairly ... well ... exploited.

"Geothermal Drilling Costs" (2006) <https://www.thedriller.com/articles/84584-geothermal-drillin...>

"Cost analysis of oil, gas, and geothermal well drilling" (2014) <https://www.sciencedirect.com/science/article/pii/S092041051...>