CHEVRON announces its first solar-to-hydrogen production project in California's central valley

[cmoreride]

Chevron New Energies, a division of Chevron U.S.A. Inc., announced it is developing a 5-megawatt hydrogen production project in California’s Central Valley.
The project aims to create lower carbon energy by utilizing solar power, land, and non-potable produced water from Chevron’s existing assets at the Lost Hills Oil Field in Kern County. This low carbon intensity (LCI) electrolytic hydrogen will be produced through electrolysis, which is the process of using electricity to split water into hydrogen and oxygen

https://www.chevron.com/newsroom/20...3eiVA9XtDQznGwLANPIIWZ1TghUxFN-vBccGYNEfWj_-4

 

[GregLocock]

2 tonnes a day, 5 MW, so say 12 MWh/tonne. HCV of H2 is 142 MJ/kg. So, 12 MWh/tonne is 12 kWh /kg is 43 Mj/kg so the process is 30% efficient overall. Believable. You then transport the hydrogen, and put it in a 60% efficnet fuel cell. 18%.






Cheers

Greg Locock


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[BrianPetersen]

Hydrogen has industrial uses, and even if not used for road-transport, producing hydrogen in this manner as opposed to from fossil fuels is still a win.

 

[TugboatEng]

In my experience industrial hydrogen is typically produced on site as the quantity required is small.

 

[GregLocock]

Brian, you are right the main use for H2 is making ammonia which is vital for agriculture and is currently responsible for 1% of anthropogenic CO2 emissions

We'd need 30000 of these 5 MW plants to replace the current process to make the hydrogen for 150 million tonnes of NH3 per year

Cheers

Greg Locock


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[LittleInch]

Greg,

There's something not right with the original numbers IMO.

A 5MW solar peak plant will produce as you say 20 to 25 MWh per day.

Doing a search shows you need something like 50Kwh electricity per kg Hydrogen from an electrolysis system. So two tons needs 100MWh. They've only got 25. Or have I got something wrong?

One is maybe that 5MW is supplemented by grid power so it is operated 24hrs/ day?

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[LittleInch]

This version

https://www.chevron.com/newsroom/2024/q1/hydrogen-facility-to-be-a-chevron-first

Looks a bit more like it. Daily electricity from a 29 MW facility is 120 to 150 MWh. I assume not all the electricity is going to be delivered to Hydrogen, but it must be>5MW.

Or reading between the lines, this 5MW is just phase 1 with an eventual total of 2 tonn per day.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BrianPetersen]

Back of notepad calcs

2 tonne H2 per day = 730 tonne H2 per day. Hydrogen accounts for 3 of the molecular weight of 17 of ammonia, the balance being nitrogen, so this would represent about 4000 tonnes of NH3 per year. Yes, this is a small part of annual NH3 production.

29 MW peak power for modern solar cells is about 150 000 square metres or 0.15 square km. Making enough H2 to replace all fossil-fuel source for all ammonia worldwide would need 4500 square km, and that's a big number, but plonked somewhere in the Sahara desert, or somewhere in the Australian outback, or in the deserts of the southwest USA, who's it going to bother?

 

[TugboatEng]

How much water would that take to clean?

 

[GregLocock]

I don't know where my numbers are wrong, I'll have another look.

What's interesting to me is that I know a couple of people working in the green hydrogen space, and my impression is that commercial feasibility is still reliant on one major breakthrough, reducing unobtanium electrode erosion. There's also the nasty (but known) problem of what you do with the hydrogen once you've made it, liquefying it takes a lot of energy, compressing it takes a lot of energy. This is why the ammonia route is attractive, turning H2 into ammonia turns the storage part of the puzzle into a solved problem.

The problem with 'free' land is that it is free for a reason. Building the infrastructure to connect it to civilisation one way or another is certainly feasible, but ramps up the capital costs no end.

Yes water availability is also an issue.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[LittleInch]

Greg, your numbers are decent, but the base data I don't think is correct.

There's no way 5MW of Solar power can produce 2 tons/ day of hydrogen.

As you say, HHV of H2 is 142MJ/ kg. Then you say it only takes 43MJ to make 1kg. So you've found free energy(!). Well done.

So either they are using a lot more electricity than 5MW or producing a lot less Hydrogen...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[EnzoAus]

2 tonnes a day, 5 MW, so say 12 MWh/tonne. HCV of H2 is 142 MJ/kg. So, 12 MWh/tonne is 12 kWh /kg is 43 Mj/kg so the process is 30% efficient overall.
I don't know where my numbers are wrong, I'll have another look.

Greg, I think your error was in inverting the division. If 43MJ elec produces 1 kg H2 with a calorific value of 142 MJ/kg, the efficiency is 142/43 (330%).

My understanding of the typical conversion efficiency is that it is about 50% excluding pressurisation and transportation. Maybe a 30MW solar farm with 5 solar hours per day will be closer to the mark for 2 tonne of H2 per day. This matches Littleinch's article.