Isothermal Electrolysis: Technology Overview

Tobe Energy has developed a fundamentally different approach to water electrolysis that achieves >92% electrical efficiency while eliminating the exotic materials, complex thermal management, and degradation mechanisms that constrain conventional electrolyzer technologies.

• •Key metrics from prototype testing:
• •94.7% electrical efficiency (LHV)
• •~75% projected CAPEX reduction vs. PEM
• •1,000+ hours tested
• •80,000+ estimated stack life (hours)

Green hydrogen remains expensive primarily because electrolysis is inefficient. Electricity accounts for 60-80% of levelized hydrogen cost, yet conventional electrolyzers convert only 60-75% of input energy to hydrogen.

PEM Electrolyzers achieve good current density but require platinum-group metals and expensive proton-exchange membranes. Membrane degradation limits lifetime. Iridium scarcity constrains scale-up.

Alkaline Electrolyzers avoid PGMs but require concentrated caustic electrolyte (25-40% KOH), creating safety, handling, and corrosion challenges. Limited turndown capability makes them poorly suited for variable renewable power.

Both technologies operate at elevated temperatures (60-90°C) and generate substantial waste heat—this isn't incidental, it's fundamental to how they work.

Tobe is a category-level rethink of water electrolysis. Rather than incremental improvements to PEM or alkaline systems, we've developed a fundamentally different electrochemical architecture.

• •Core subsystems:
• •Power Electronics: Converts input to controlled pulse waveforms using proprietary patterns
• •Electrolysis Module: Membrane-free design using 304 SS construction
• •Gas Handling: Simplified separation (no membrane → cleaner streams)

• •Key differentiators:
• •No Membranes — zero proton-exchange membrane
• •No Caustic — works with dilute or pure water
• •No PGMs — zero platinum or iridium
• •Near Ambient — operates <30°C, no active cooling

All figures represent measured system performance, not theoretical or stack-only values. We report LHV efficiency as the industry standard.

• •Electrical Efficiency (LHV): 94.7% — Stack performance at nominal operating point
• •System Efficiency: ~42.23 kWh/kg H₂ — Including power electronics and gas handling
• •Turndown Range: 10–100% — Maintains efficiency across operating range
• •Response Time: <1 second — Grid-following capability for renewable integration
• •Startup Time: Immediate — No warm-up period required
• •Operating Pressure: Up to 350 psig — Reduces downstream compression
• •Operating Temperature: <30°C — Near-ambient, minimal thermal management
• •Ambient Range: -30°C to +50°C — Outdoor installation without climate control
• •H₂ Purity: >99% — Higher purity available with standard PSA

Tobe's architecture eliminates the primary failure modes that limit conventional electrolyzer lifetime. Nothing in the stack gets "used up" during operation.

• •Failure modes eliminated:
• •Membrane Degradation — No membrane in system
• •Catalyst Poisoning — No catalysts required
• •Thermal Cycling Fatigue — Isothermal operation
• •Caustic Corrosion — Dilute/neutral electrolyte
• •Electrode Degradation — Low-temp with corrosion-resistant 304 SS

• •Design philosophy:
• •Commodity materials — 304 SS uses globally available supply chains
• •Modular architecture — Individual cells serviceable without system shutdown
• •No single points of failure — Redundant sensing and control throughout
• •Industrial standards — Components selected for proven reliability

Tobe systems scale through modular multiplication of proven cell designs.

• •Product line:
• •Tobe-25: 25 kW, ~12 kg/day, compact skid — Distributed, pilot, R&D
• •Tobe-250: 250 kW, ~120 kg/day, 20' container — Commercial, fleet fueling
• •Tobe-2500: 2.5 MW, ~1,200 kg/day, multi-container — Industrial, hub-scale

• •Manufacturing economics:
• •Prototype cost: ~$446/kW (includes NRE and low-volume inefficiencies)
• •Projected at scale: ~$177/kW (at MW-scale volumes)

Conventional PEM electrolyzers cost $700–1,200/kW at scale. Tobe's projected $177/kW represents ~75% reduction from PEM.