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Eletrolyser Calculator

Calculate electrolyser size

Electrolyser Calculator
Electrolyser Calculator
Equations:

Equations

Hydrogen Production (kg/day)

The hydrogen production rate is calculated as:

\[ \text{Hydrogen Production} = \frac{P \times \eta \times 24 \times \text{Load Factor}}{39.44} \]

Where:

  • \( P \) = Power (MW)
  • \( \eta \) = Efficiency (%)
  • 39.44 = HHV (kWh/kg)

Energy Required (MWh/day)

The energy required is calculated as:

\[ \text{Energy Required} = \frac{\text{Hydrogen Production} \times 39.44}{\text{Load Factor}} \times \frac{1}{1000} \]

Where:

  • 39.44 = HHV (kWh/kg)
  • Load Factor (%)

Water Required (m³/day)

The water required is calculated as:

\[ \text{Water Required} = \frac{\text{Hydrogen Production} \times 10}{998} \]

Where:

  • 998 is the density of water (kg/m³)

📖 Variables Legend

Variable Description Unit
\( P \) Power MW
\( \eta \) Efficiency %
\( \text{Load Factor} \) Load Factor %
\( \text{Hydrogen Production} \) Hydrogen Produced kg/day
\( \text{Energy Required} \) Energy Consumption MWh/day
\( \text{Water Required} \) Water Consumption m³/day

What is Water Electrolysis?

Water Electrolysis is a chemical process that uses electricity to break down water into its individual elements (hydrogen and oxygen). It typically involves the use of an electrolyte solution, which conducts electricity, and two electrodes (an anode and a cathode) submerged in the solution.

When electric current is applied, positive hydrogen ions migrate toward the negative electrode (cathode), where reduction occurs, and negative ions migrate toward the positive electrode (anode), where oxidation happens. Hydrogen is formed at the cathode while oxygen is produced at the anode.

Why quick estimations are important?

Hydrogen projects move fast—and early-phase estimates can make or break their success. Whether you’re pitching to investors, sizing equipment, or evaluating renewable energy integration, rough calculations help you:

  • Spot feasibility gaps: Is the required power realistic for your site’s solar/wind capacity?

  • Budget smarter: Ballpark costs for electrolysers, energy, or hydrogen storage.

  • Win stakeholder trust: Back proposals with numbers (even if they’re approximate).

  • Adapt to change: What if demand doubles? What if efficiency drops 10%?

Tip: Use our electrolyser calculator to toggle between “power → H₂” and “H₂ → power” modes—because flexibility is key in early planning!

Electrolysers 101: Types and Best Uses

Not all electrolysers are created equal. Here’s a quick guide:

  1. Alkaline (AEL):

    • Cheapest, mature tech.

    • Great for large-scale industrial projects (ammonia, refineries).

    • Needs stable power—struggles with solar/wind’s variability.

  2. PEM (Proton Exchange Membrane):

    • Compact, responsive: Handles fluctuating renewables.

    • Higher cost, but ideal for small-to-medium projects (fueling stations, grids).

  3. Solid Oxide (SOEC):

    • High efficiency (needs extreme heat—pair with waste heat or nuclear).

    • Emerging tech: Watch this space for hydrogen-as-energy-storage projects.

Fun fact: Newer types like AEM (Anion Exchange Membrane) aim to merge AEL’s cost + PEM’s flexibility!

What Affects Hydrogen Production (or Power Needs)?

Your results depend on more than just math. Key factors:

  • Power quality: Voltage spikes or intermittent supply can reduce efficiency.

  • Temperature & pressure: Higher temps boost PEM/SOEC efficiency but require energy to maintain.

  • Electrolyser age: Efficiency dips ~0.5%/year—factor this into long-term projects.

  • Water purity: Impurities = more maintenance + lower output.

  • Load factor: A 1 MW electrolyser running 50% of the time makes half the H₂ of one at 100%.

Pro tip: When sizing power for a target H₂ output, don’t forget auxiliary loads (cooling, controls)!

Common Mistakes to Avoid

Even experts slip up. Steer clear of these pitfalls:

  1. HHV vs LHV confusion: Using the wrong value skews efficiency by ~18%! (More on this below.)

  2. Ignoring degradation: Assuming Year 1 efficiency lasts forever.

  3. Overlooking “hidden” power: Auxiliary systems can eat 5–10% of your total energy.

  4. Unit mix-ups: Check kg vs tons, kW vs MW, and hours vs years.

  5. Assuming 100% uptime: Real-world load factors are often 60–80%.

Use our calculator to test scenarios—like “What if my load factor drops to 70%?”—and dodge costly errors.

HHV vs LHV: Why It Matters

Hydrogen’s energy content depends on how you measure it:

  • Lower Heating Value (LHV): ~33.3 kWh/kg. Excludes heat from vapor in exhaust.

    • Used for electrolyser efficiency (since water input is liquid).

  • Higher Heating Value (HHV): ~39.4 kWh/kg. Includes all energy, even from vapor.

    • Used for combustion/storage (e.g., fuel cells).

The trap? If you calculate power needs using HHV instead of LHV, you’ll underestimate by ~18%. Always check which value your datasheets use!

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