Electrolyser modelling for green hydrogen

The role of hydrogen in our future energy systems is a very hot topic right now. Most folks acknowledge it has a part to play, although debate rages over whether it’s the leading lady or a walk on role.

The Yuri project in WA caught our eye as it’s all about replacing existing fossil-derived hydrogen with green hydrogen produced from electrolysers powered by renewable energy. The project then uses that hydrogen onsite as it provides it to the big ammonia production facility next door. Sensible stuff.

The project is a collaboration between Yara Fertilziers and Engie and aims to demonstrate that a 10MW electrolyser coupled to 18MW of solar and an 8MWh/5MW battery can produce about 640 tonnes of green hydrogen a year.

Curiosity got the better of us so we decided to spin up a simulation in @Gridcognition and see how that looked.

Assumptions:

• 18MW of single-axis tracking solar
• 10MW electrolyser that requires 52kWh of electricity to produce 1kg of hydrogen, meaning an average daily energy requirement of 92MWh to produce 1.75 tonnes of hydrogen per day (640 per year)
• 8MWh/5MW lithium-ion battery with the typical specs
• Unlimited ramp rate on the electrolyser to flex to the variable solar output
• We included a backup genset to cover any unserved load that could be met by the solar + battery.

Results:

• The existing design does pretty well with about 3% or 1,000MWh of electroyser energy required to be provided by the genset (brown on the charts) i.e. is basically unserved load if you only had the solar and battery. Of course, you could choose to not run the electrolyser during these periods
• Not surprisingly it was the winter months where the solar + battery struggled a bit.
• Adding a bit of wind helps, although it isn’t a free option. 10MW of wind reduced the unserved load to just 230MWh a year (0.7%)

There are doubtless lots of assumptions we have wrong here, it’s a bit of fun just based of the published details, but expect a lot more of these projects over the coming years.