Hydrogen Keynumbers

This is an article about numbers, explaining how to use simple maths to understand a subject such as hydrogen. Each of the calculations (models) is available on keynumbers.com, I've included the links below each image so that you can use the maths including the sources and explanation of what context to use them in.

And... the pages are all curated in a keynumbers group so it's easily accessible instead of trying to trawl through my posts!

https://keynumbers.com/#/group/114-hydrogen-unit-conversion-4947

https://keynumbers.com/#/public/page/114-market-size-11331

Hydrogen price per unit of energy

https://keynumbers.com/?#/public/page/hydrogen-price-per-mwh-11456

Historically hydrogen has been used as feedstock to make fertilizer and industrial chemicals. It's now being touted as a replacement for natural gas such as in power plants and other energy systems.?

In order to compare to natural gas, divide the weight of hydrogen (1 kg) by the energy density (39.4 kWh/kg)?or in gigajoules (142 MJ/kg)

https://keynumbers.com/?#/public/page/hydrogen-price-per-energy-unit-11411

Note: as a lot of natural gas is priced using the higher heating value (gross calorific value), use 39.4 kWh/kg. If wanting to understand the price per lower heating value, then change the dial to 33 kWh/kg or 121 MJ/kg respectively.

Useful For:?

• Australian domestic natural gas prices $A 4-8/GJ although recently they have trended around $A 18/GJ
• Compare to Henry Hub which is the benchmark for USA natural gas, usually trades between $2-4/MMBTU.? (Note: 1 MMBTU = 1.055 GJ)
• Compare to LNG, for example the JKM (Japan Korea Marker) has historically traded between $8-15MMBTU?
• European gas is priced in MWh with the Dutch TTF historically trading between EUR 15- 20/MWh
• If comparing as a feedstock for powerplants, divide by the heat rate of the plant (gas peakers are about 35% efficient) so as to compare to solar and wind projects.

Green Hydrogen Requirements

https://keynumbers.com/?#/public/page/114-energy-for-green-hydrogen-11269

How much electricity is required?

https://keynumbers.com/?#/public/page/page-11409

• The market for hydrogen is 90-100 million tonnes with projections of up to 250 million tonnes by 2050
• Assume each kilogram requires 50 kWH of electricity (Source:?Paul Martin)

Is that a lot??

If you made all the hydrogen via electrolysis, it would be the same quantity as the United States of America annual electricity production. 4550 TWh.

Useful For:?

• Comparison to country electricity generation. The United States of America uses 4550 TWh/yr (Source: BP Statistical Review)
• Produce 250 MT/yr and it's close to all the electricity generated by the Asia/Pacific region (14,550 TWh)?
• Dial down the percentage to 2% to understand current electricity requirements from electrolysers.

How much hydrogen does an electrolyser produce??

https://keynumbers.com/?#/public/page/electrolyser-requirements-114-11438

• 1 Kilowatt of electrolyser, running 100% of the time for a year (8760 hours in a year) will consume 8760 kWh of electricity,
• If you assume each kilogram of hydrogen requires 50 kWh of electricity, then the electrolyser will produce 175 kg each year.

How does capacity factor impact production?

Nothing is perfect and every equipment will need fixing or time for regular servicing. For renewables, it's not sunny or windy all the time!?

• Lazard has a capacity factor of 90% for running electrolysers,
• A study by the University of NSW had a configuration of 1.5kW of Solar to 1kW of Electrolyser which produced 60kg a year or 40kg per 1kW. This works out to be about 23%.?

How much electricity to do you need??

https://keynumbers.com/?#/public/page/114-energy-for-green-hydrogen-11269

• Paul Martin has a great?article?on electrolyser efficiency and the simple answer is 50 kWh/kg which is easy to remember,
• If you want the technical, IRENA has?published?efficiency based on tech type in kWh/kg: Alkaline: 50-78, PEM 50-83, SOEC 40-50, AEM 40-69
• Don't forget there's new technology such as Hysata who?claim?42kWh/kg (higher heating value)

Hydrogen from Fossil Fuels

https://keynumbers.com/?#/public/page/hydrogen-per-normal-cubic-meter-11501

You get used to kilograms and then the industry quotes in normal cubic metres!?

https://keynumbers.com/?#/public/page/hydrogen-per-normal-cubic-meter-11501

• Large scale hydrogen plants that use natural gas as the feedstock sometimes quote their production rates in normal cubic metres per hour
• 1 kg of hydrogen is 11.13 nm^3

?Useful For:

• For comparing SMR plants with green hydrogen projects.
• To understand daily production, turn the dial to 24 hours, 8760 for yearly production.?

How much natural gas is required to make a kilogram of hydrogen?

https://keynumbers.com/?#/public/page/natural-gas-required-for-smr-11326

• The US Argonne Laboratory GREET model has calculated that a? Steam Methane Reforming plant (SMR) process is 72% efficient in converting the energy content from natural gas into hydrogen.??

?Useful For:

• Understand the total amount of natural gas required to make hydrogen
• Understand the impact of feedstock price on hydrogen prices.?

What are the emissions from hydrogen?

https://keynumbers.com/?#/public/page/emissions-from-hydrogen-12949

• Most hydrogen is produced from natural gas. Each megajoule emits 75grams of CO2, there is a 120 MJ in a kilogram of hydrogen or the equivalent of 9kg.
• In addition, methane has a global warming potential of 86 over 20 years. Including indirect and fugitive emissions can double the CO2e emissions from hydrogen.?

?Useful For:

• Change the tonnes to 45m to get the emissions from global hydrogen via natural gas.?
• Change the fugitive emissions to zero to see just the CO2 component.

More Keynumbers!

As mentioned, I run a website keynumbers.com. If you would like to understand more on the maths, add a comment and I'll look to create a model from it.