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1 How cryonics vessels behave during a blackout

Cryonics patients are stored inside large, vacuum-jacketed “thermos-like” dewars that are passively cooled by a pool of liquid nitrogen (LN₂) at –196 °C. The refrigeration is purely physical; no pumps or compressors are needed. If the mains power fails, the dewar just keeps boiling off nitrogen a little faster and vents the gas through relief valves, but the temperature inside hardly budges.

2 Typical hold-time before warming becomes a problem

Because the only heat input is through the dewar walls, boil-off is slow—about 0.5 % of the LN₂ volume per day for large 1 000–2 000 L “whole-body” vessels.

• A 2 000 L unit therefore loses roughly 10 L/day.

• If it starts full, it takes ≈180–200 days before the liquid is gone and the patient rises above −130 °C (the glass-transition point where real damage accelerates).

Facilities normally top up every 2–4 weeks and keep extra bulk tanks on site, so a weeks-long blackout poses essentially zero risk; you would need many months without any nitrogen resupply before real warming begins.

3 How likely is a resupply failure driven

only

by normal grid outages?

A convenient proxy is the SAIDI (System Average Interruption Duration Index):

Region Average unplanned outage per customer (2022–24) Ratio vs. US
United States 5.6 h / yr 1×
Germany (typical of continental EU) 12.8 min / yr ≈ 1⁄26

Even in the less reliable U.S. grid, annual outages are measured in hours, not weeks. Delivery logistics (drivers, road access, industrial-gas plant downtime) dominate LN₂ availability, and those are usually restored within a few days after storms or regional failures. The chance that an ordinary blackout snowballs into a >3-month nationwide nitrogen shortage is comfortably <10⁻⁴ per year—orders of magnitude lower than the already-tiny chance you will ever be revived.

4 Extraordinary threats: EMPs and Carrington-class solar storms

Carrington-level geomagnetic events have an estimated ≈12 % probability per decade—about 1.3 % per year. A high-altitude nuclear EMP is harder to quantify, but U.S. national-security analyses often use a ∼0.4 % per-year probability of nuclear exchange. Both phenomena could fry transformers and cut electricity for months, halting bulk-gas plants and diesel-fuel supply chains.

Cryonics organizations are acutely aware of this: Alcor’s internal risk assessments list EMP or strong solar discharge as canonical worst-case scenarios that could “take years to repair.”

5 So what happens to the patients if an EMP really does hit?

  1. Immediate safety – Dewars remain cold for many months (see §2).
  2. On-site reserves – Most facilities keep several weeks to months of LN₂ in outdoor bulk tanks.
  3. Redundant production – Newer operators (e.g., European Biostasis Foundation in Switzerland) site themselves in politically stable areas and are moving toward on-site PSA/cryocooler nitrogen generators, eliminating dependence on external plants.
  4. Power-agnostic options – LN₂ can be produced with mechanical compressors or diesel gen-sets; it is WWI-era tech and could be restarted locally faster than a national grid.

Even assuming a Carrington-class storm (47 % cumulative probability over 50 years), you would still need all four layers of defence to fail before warming occurs. Conservative fault-tree models put the integrated thaw risk at roughly 0.5–5 % over half a century.

6 America vs. Europe—relative thaw risk

Factor United States Europe (continental EU / CH) Net effect
Routine grid reliability Lower (hours of SAIDI) Higher (minutes of SAIDI) Europe safer
Target value for nuclear EMP Higher (prime adversary of DPRK, Russia, etc.) Lower Europe safer
Latitude for solar GICs Mid-latitudes, long east-west lines—moderate vulnerability Similar or slightly higher at high-latitudes (Nordics) but with better transformer grounding ≈ Tie
Political stability & diesel logistics Variable by state; resilience plans uneven High in CH/DE/NL; mandatory strategic fuel stocks Europe safer
Cryonics infrastructure today Two large, mature providers (Alcor, CI) with decades of operational history New but designing in redundancy (EBF, Tomorrow Bio) U.S. has more experience; EU gaining

Overall, *the probability of an involuntary thaw caused specifically by grid loss or EMP is probably 2-3 × lower in Europe than in the U.S. today, but in both regions it remains a single-digit-percent lifetime risk at most. All other uncertainties in cryonics (cellular repair, legal continuity, revival technology) are still many orders of magnitude larger.

7 Practical take-aways if you care about this risk

  • Ask your provider for hard numbers :– How many days of liquid nitrogen are stored on site?– Do they have an in-house generator or contracts with multiple gas suppliers?– What is the fuel autonomy of their backup diesel plant?
  • Favor facilities with on-site nitrogen generation (PSA + cryocooler) or those located near an air-separation plant.
  • Push for written disaster-response SOPs that cover EMP-class events.
  • Consider geographic diversification: some members fund storage in two separate dewars or even two continents.

Bottom line: unfreezing due to a routine blackout is virtually impossible; only a prolonged, civilization-disrupting EMP/solar storm could do it, and even then the absolute odds are a few percent over many decades. Choosing a well-engineered, redundancy-minded European site edges that number even lower.