The Availability Gate
The honest availability finding: modelled ~0.86-0.995 against a Tier III target of 0.99982 - a 30-100x downtime shortfall stated as a physics-and-operations fact.
Definition
Availability A is the long-run fraction of wall-clock time a unit delivers rated service. For a repairable unit with mean time between failures MTBF and mean time to repair MTTR, the steady-state estimate is A = MTBF / (MTBF + MTTR). Downtime fraction is U = 1 - A. The whole point of the gate is that hyperscale Tier III uptime (0.99982) corresponds to about 95 minutes of downtime per year, whereas our modelled burner range corresponds to hours-to-weeks per year.
# Downtime per year for an availability figure
HOURS_PER_YEAR = 8766.0
for A in (0.86, 0.95, 0.99, 0.995, 0.99982):
U = 1.0 - A
down_h = U * HOURS_PER_YEAR
print(f"A={A:<8} downtime={down_h:8.2f} h/yr ({down_h*60:8.1f} min/yr)")
# A=0.86 -> 1227.24 h/yr
# A=0.995 -> 43.83 h/yr
# A=0.99982 -> 1.58 h/yr (Tier III target)Why the gate is real
The burner availability range 0.86-0.995 is a modelled envelope, not a marketing floor. It aggregates plug-coil duty limits, cryogenic and RF subsystem reliability, and maintenance access. Against 0.99982 the shortfall in tolerable downtime is 30x at the optimistic end and roughly 100x at the pessimistic end. This is one of the four canonical burner gates and it is not translated into any economic statement here - it is a downtime fact.
| Claim | Honest? |
|---|---|
| Single MetroVolt unit is a sole Tier-III source | 0 |
| Fleet + storage + grid tie can approach Tier-III at facility level | 1 |
| The gap is 30-100x in downtime today | 1 |
How we close the gap on paper
- N+1 and N+2 unit redundancy at the facility level rather than a single machine
- Graceful degradation to partial power instead of trip (see Graceful Degradation)
- Predictive maintenance to convert unplanned outages into scheduled ones
- Fleet model propagation so each new unit inherits reliability learning
The model, its inputs, and its Monte-Carlo treatment are documented in Availability Modeling. The gate stays visible in every one of those pages.