Type III vs Type IV PET for UAV Fleets: 5-Year Total Cost of Ownership
“Type III aluminium-lined cylinders are the conservative choice for hydrogen UAVs” is industry orthodoxy. The spreadsheet, run honestly, says otherwise — at least for daily-fill commercial fleets. Here’s the 5-year cost-of-ownership math, with the numbers an integrator would see in real procurement.
The fleet we’re modelling
Sample fleet:
- 100 hydrogen-fuel-cell UAVs in a commercial inspection / surveying / cargo operation
- Each UAV flies 4 sorties per working day, 250 working days per year = 1,000 sorties/year/UAV
- One cylinder per UAV (some operations swap cylinders mid-day; the math scales similarly)
- Cylinder spec: 3-litre, 300 bar working pressure, M18 × 1.5 thread
Each cylinder sees ~1,000 fill cycles per year. Over 5 years that’s 5,000 cycles per cylinder. Hold this number — it determines everything.
Type III aluminium-lined: the legacy default
- Mass: ~2.5 kg for a 3-litre at 300 bar
- Service life: in legacy industrial use, Type III aluminium-lined cylinders are spec’d at 5,000–15,000 cycles. To compete with MEYER® on weight, several Type III makers now publish UAV-class designs qualified to as little as 500 cycles. At 1,000 fill cycles per year, that is a retirement event inside year 1 — plus the 15- or 20-year calendar cap. Lighter Type III is not cheaper Type III: it front-loads the replacement bill and pushes the design closer to its fatigue envelope, raising failure-mode risk.
- Replacement timing: at 1,000 cycles/year, expect cylinder retirement at year 5–10. Conservative planners assume 5 years.
- Indicative unit cost: €1,200 (varies by supplier and qualification scope)
Over 5 years for 100 cylinders: €120,000 in cylinder spend, with a near-certain replacement event at year 5 — adding another €120,000 if you continue the operation into year 6.
MEYER®: the lighter alternative
- Mass: ~1.3 kg for the HDRX-030 (3-litre, 300 bar). About 1.2 kg lighter than Type III.
- Service life: 10,000+ cycles, NLL qualified — no calendar replacement.
- Replacement timing: none expected within 5-year horizon.
- Indicative unit cost: €1,800–2,200 for low-volume orders, falling to €1,400–1,700 at fleet scale (100+ cylinders).
Over 5 years for 100 cylinders at €1,800 unit cost: €180,000 in cylinder spend. Higher upfront — that’s the part Type III defenders point to. But the spend stops there.
The real comparison: per-flight revenue
The 1.2 kg mass delta translates to flight time and payload. For a 15-kg-class hydrogen UAV, 1.2 kg saved on the cylinder typically buys ~3 minutes of additional flight time per sortie (or equivalent payload uplift).
- Commercial inspection sortie: typical revenue €150–300, dependent on flight time
- 3 minutes additional flight per sortie — roughly +5–10% utilisation on a 30-minute mission
- For 100 UAVs × 1,000 sorties/year × €15 incremental revenue per sortie = €1.5M/year in fleet-level revenue uplift
The €60k extra upfront cylinder cost (MEYER® vs Type III) is recovered in ~2 weeks of fleet operation. Over 5 years, the revenue delta is >€7M. That’s before counting downtime savings from no replacement event.
5-year TCO summary
| Metric | Type III (Al-lined) | MEYER® (HDRX) |
|---|---|---|
| Mass per cylinder | 2.5 kg | 1.3 kg |
| Cycle life | 5,000 nominal | 10,000+ NLL |
| 5-year unit cost (100 fleet) | €120,000 | €180,000 |
| Year-5 replacement liability | €120,000 | €0 |
| Cumulative revenue uplift (mass delta) | baseline | +€7,500,000 |
| 5-year cost-benefit | baseline | +€7.4M better |
When Type III still wins
Three cases where Type III aluminium remains the right answer:
- Long-duration storage of hydrogen or helium — the polymer liner permeation rate (~30%/month for H₂ at 300 bar) becomes meaningful when the cylinder sits filled for weeks. Daily-fill UAV operations don’t see this.
- Programmes that already qualified Type III — re-qualification cost can dwarf the operational savings.
- Cost-floor operations where unit price is the dominant constraint and mass / cycle life don’t translate to revenue.
For commercial daily-fill UAV fleets — which is most of the H₂-drone industry today — none of these conditions hold.
Run your own numbers
The cost model above uses indicative figures. Your actual fleet will have different sortie revenue, sortie length, fleet size, and cylinder unit cost. Run the math with your own numbers in our 5-Year Cost of Ownership Calculator — the comparison is built on the same model, with editable inputs.
