Electrolyzer

Hydrogen Generator

Summary: 1 kg of hydrogen every 3 days - with $4k off-the-shelf equipment today. Integrating to larger sizes and using open source technology, we can likely lower this 3x at point of purchase and 30x over lifetime. Spicer Electrolyzer already showed a $3k/1 kg/day system. Capital cost for large-scale systems is $430/kW generation capacity (about 1/2 kg/day system) - which is over 10x cheaper than the off-the-shelf system above [1]. Clear indication of $1000/ 1 kG/day production exists. Key would be designing for lifetime - with easy maintanance. Lifetime design is a strength of an open source ecosystem. OSE collaborative design predicts meeting or exceeding of industrial scale efficiency on a village scale.

Separating Hydrogen Generator

• Diagram of system - [2]. Paper has info contacts at NREL, and comparison of PEM to alkaline.
• alkaline electrolyzer stack - price not shown - [3]
• 200 cc/min at 3-8 bar - $9k - [4]. With 1440 minutes/day - or 0.3 cu meter per day [5].
• 1000 cc/min - $3280 - for 1000 ml/min - 1.4 cu meter/day. Alkaline, 4 bar. That is 130 grams of hydrogen per day. [6]
  • Redo the same - and 10x lower cost.
  • Need 3 hours of Honda EU1000 generator - or 2.7 kWhr.
• 500 cc/min - $700 - see below at Sourcing section
  • x5 = $3500 for 2500 cc/min or 3.5 cu m per day (about 1000 gal propane tank with no compression (thus 500 gal at 4 bar can handle 2 days worth of generation), but if it is solar generation, that is 8 days of storage)) [7]. Or 290 grams per day (kg of hydrogen is about 11 cu m [8])
• Power extraction - If 0.6 gal used for 7 hours at 1/4 power with Honda EU1000 - the gen set can do 7 hours at 200W. Or 1.4 kWhr. It advertises 3.2 hours at full power - or nearly 3 kW. Note that 3.2 hours at rated load of 900W - nearly 3 kWhr - on 0.6 gal gas. So it's more efficient to run at full power, which wastes less energy due to 'reciprocating pump loss'.
• Bottom line - 290 grams per day of hydrogen - less than 1/3 kg equivalent - means about one half the 0.6 kg (0.55 gal [9]) equivalent tank of the Honda EU1000. Thus, we get a power of about 1.5 kWhr from the daily generation of hydrogen using a Honda1000EU generator at full power. Not bad. That is marginal full power storage from an eco-home with smart energy. If designed for smart energy use, then this solar hydrogen route could be completely viable. Using $3500 in hydrogen generation. For storage in a Propane Tank - bottom line is
• Zirfon PERL is common electrolyzer separator material - [10]. It is a polysulfone (3D printable) and 85% ZrO2 nanoparticles blend. ZrO2 - [11]
• Both stainless steel and nickel work as electrodes - [12]
• Alkaline Electrolyzer Design

Slow Life Electrolyzer

• Say we want to travel into town once per week - one gallon of fuel used - to travel 50 miles round trip.
• The $700 electrolyzer (500 cc/min) gets us 0.3 kg every 5 days. Every 15 days - we build up enough hydrogen for a trip to town in an efficient car (50 mpg or more).
• We would need 2-3 such electrolyzers - about $2k - to generate a gallon of gas equivalent.
• If an average person does 10000 miles travel per year - we need 200 gallons nominally.
• We get about 58 grams per day from one 500 cc electrolyzer. We need 0.6 kg/day to power up a regular car with average driving schedule. That is still only 10 of these electrolyzers! Quite doable.
• Summary: an average Mercan can make their own hydrogen to keep up with their car - for $7k in off-shelf electrolyzers. This means that an average american [13] pays back for their stack in 4 years. This is an enterprise worth pursuing, but only through Collaborative Development.

Sourcing

Alkaline

• 150W, 300 cc/min - $600 - [14]
• 500 cc/min - $700 - [15]

PEM

• $34k/2000cc/min at 16 bar. [16]
  • Produces 1/4 kg/day.
  • Lasts 40000 hrs according to internet [17]
  • This is about 400 kg of hydrogen produced - or $85/kg just for the electrolyzer. Fuggeddaboudit.

DIY Separating

• thediyscienceguy@gmail.com - [18]

Mixing Generator

• $200 for 6 lpm - but this is HHO, not H + 0
• Graphite plates work well - [19]
• Wet vs dry cell design - [20]

Summary

• 500 cc/min = 0.7 cu m / day [21]
• 0.7 cu m = 0.06 kg. [22]
• This means 5 of these give 0.3 kg/day - at a cost of $3100 of equipment
• Off-the-shelf - 1 kg/day of hydrogen costs $10k.
• Compare to the Spicer Electrolyzer - which can likely be produced for $100 per cell - and $3k per 1kg/day capacity. At scale, the Spicer system can likely be much more cheap.
• This is worth pursuing today.

Internal Links

• Alkaline Electrolysis

External Links

• A 2008 Report Titled "A Low-Cost High-Pressure Hydrogen Generator" (Move this to High Pressure Electrolysis or a similar page once that is made)
• A 2022 Paper Titled "The case for high-pressure PEM water electrolysis" (Move this to High Pressure Electrolysis or a similar page once that is made)
• A 2021 Paper Titled "Evaluation of Diaphragms and Membranes as Separators for Alkaline Water Electrolysis" (Move this to Alkaline Electrolysis / Alkaline Electolyzer / Alkaline Electrolyser once that/those pages are made)
  • AN OPEN ACESS PAPER? How Refreshing!
• A 2021 Paper Titled "A membrane-free flow electrolyzer operating at high current density using earth-abundant catalysts for water splitting"
• A 2017 Report Titled "Manufacturing Competitiveness Analysis for PEM and Alkaline Water Electrolysis Systems" (Aimed towards the conventional Mass Manufacturing Audience, but it still may contain useful information)