We're not here to sell you a battery. We're here to help you solve whatever's actually driving your electrification project. A CARB compliance deadline bearing down on the fleet? A newbuild spec still open on the propulsion package? A hybrid retrofit already underway that needs a safer buffer than the pack you spec'd two years ago? Tell us the vessel and where you are in the build, and we'll tell you honestly whether a non-flammable VSB buffer is part of the answer, not assume it is before we've heard your specifics.
CARB's Commercial Harbor Craft rule (with EPA Clean Air Act authorization granted January 6, 2025) requires harbor tugs to meet Tier 3/4+ standards or go zero-emission on a schedule running to 2032, pulling the ports of LA, Long Beach, San Diego, and San Francisco toward electric-assist tugs now, not later. Washington State Ferries has committed $3.98B to electrify up to 16 vessels and the terminals behind them. The propulsion decision is being made now; the buffer chemistry inside it isn't settled yet.
Sources: EPA (CARB waiver, Jan. 2025) · Washington State Ferries electrification program
It takes the short steps a power-sized lithium pack isn't rated for. Hybrid vessels mostly buy marine lithium rated around 3C continuous. Where a peak lasts minutes, that pack is the right answer and VSB doesn't beat it. Where a small pack bought for power has to cover a step of seconds above its rating (a plant changeover, a generator coming online, a hard thruster step), VSB can sit beside it on the bus and take the step. VSB is not lighter per kWh than lithium. It is a power buffer beside the lithium, not a replacement for it.
Where the physics turns. Against a 3C lithium pack, VSB comes out lighter only for bursts under about three minutes, and only if it can hold well above 17C for the whole burst. The shorter the step, the bigger the edge. How long a VSB pack can hold high power is the number that decides each case, and it's the first thing we're measuring with Vanadis. Until it is published, we size at a conservative 20C, where VSB roughly ties lithium on mass.
It removes a documented fire-risk category from the battery room. The marine incident record on lithium is real and recent: the container ship Genius Star XI (Dec. 2023, cargo-shift thermal runaway, $3.8M in damage), Höegh Xiamen (June 2020, 8-day lithium fire, total loss, $40M), and Morning Midas (June 2025, three-week fire, vessel lost) all involved cargo lithium batteries, not propulsion packs, but the same underlying chemistry risk a hybrid retrofit brings on board. Closer to the passenger side, Norled's ferry MF Ytterøyningen suffered a battery-room fire and overnight gas explosion in October 2019 that hospitalized 12 firefighters, traced to a coolant-circuit failure: the kind of active-cooling dependency Vanadis says VSB doesn't need across its −40°C to +100°C range.
This isn't the whole story, and we won't pretend it is: on long-crossing, energy-dominant duty (ocean-going ferries, cruise ships, anything where the discharge is hours long rather than minutes), a sustained-energy pack sized for that duty is the right call, and VSB is not the right buffer for that duty cycle. The same goes for battery-electric and large-pack hybrid tugs: a pack sized to last a shift is never short of power. VSB is TRL 6-7, field-proven in grid stabilization deployments (Sweden, Poland) and fleet trials, not yet type-approved or fielded on any tug, ferry, OSV, or CTV. This is a first-pass positioning page, not a sized deployment or case study. Tell us your vessel and duty cycle and we'll listen before we pitch anything back.
Is the vessel's battery bought for power or for energy? And does the peak it can't cover last seconds or minutes? Our read from public data, vessel type by vessel type. If yours isn't here, those two questions are the test, and we'll run it with you.
A pack bought for power that has to cover seconds-long steps above its rating
Depends on how long a battery must hold as spinning reserve; we're finding out
The pack is sized to last a shift, so it's never short of power
Energy-dominant duty; a pack sized for energy is the right call
Sized for onboard hybrid propulsion or power-buffer duty: here's how the chemistry stacks up.
| What matters on board | Lithium-ion (NMC / LiPo) | LFP (LiFePO₄) | VSB (Vanadium Solid-State) |
|---|---|---|---|
| Fire / thermal runaway | Propagating; needs suppression, vents, setbacks | Reduced but real: runaway above ~270 °C | Non-flammable chemistry; no thermal runaway or propagation (manufacturer claim, independent testing pending) |
| Cycle life (deep) | 500-2,000 | 3,000-6,000 | 15,000+ (Vanadis projection) |
| Service life | 8-10 yrs | 10-12 yrs | 20+ yr design life (Vanadis projection; not yet fielded at sea) |
| Power response / fast-charge | 0.5C-3C | 0.5C-3C (EV-class cells) | Up to 60C at the cell-module (Vanadis); how long a pack holds high power is not yet published, so we size at 20C |
| Operating temperature | 0 to +45 °C (active cooling required) | −20 to +60 °C (still wants cooling) | −40 to +100 °C ambient; no active cooling needed (Vanadis) |
| Freight / DG class | UN 3480 / 3481, Class 9; ≤30% SoC on aircraft | UN 3480 / 3481, Class 9; same DG burden | Dead-safe at 0 V; UN number pending, no blanket DG exemption claimed. |
| Recyclability | ~50% recoverable | ~50% recoverable | ≈85% of cell material recovered |
Specifications indicative; final ratings confirmed per project. VSB has not yet completed marine type-approval (DNV/ABS/class society) or a fielded tug, ferry, OSV, or CTV installation.
Whatever it is, a CARB compliance clock, a newbuild spec still open, a retrofit already underway, or an insurer asking harder questions about the battery room, you're not wrong to want a straight answer instead of a sales pitch. Tell us what's going on and we'll connect it directly to whether VSB actually fits.