Hydrogen to AC -- From the Fuel Cell to the Grid

[Sclerostin]

Fuel cells quickly provide electricity from H2 when switched on. But what exact steps get to Grid voltage? Are there many small inverters, and if so, how do they keep the output in step? What sort of efficiencies are there?

 

[anorlunda]

Just like solar pv panels, inverter electronics convert DC to AC, step up the voltage, match frequency and phase with the grid, and provide protection from McDougall and emergencies. They work the same for fuel cells. Sometimes they are called just "utility interface" boxes.

You can look up fuel cell variants, and the efficiency of each on Wikipedia.

For reasons I don't understand, domestic fuel cells are much more successful in Japan than in the USA.

 

[jim hardy]

But what exact steps get to Grid voltage? Are there many small inverters, and if so, how do they keep the output in step?

Grid scale inverters are becoming more common.

Here's one that'll handle 5MVA at 690 Volts (about 4180 amps)
about 12 feet tall, weighs 4 tons.

https://new.siemens.com/global/en/products/energy/medium-voltage/systems/sinacon-pv.html

 

[Sclerostin]

OK thanks. That is a help.
But given the Fuel Cell only pushes a few volts (how many, not sure) are there lots of little inverters or do you add the DC volts up and convert at some high voltage?

 

[jim hardy]

But given the Fuel Cell only pushes a few volts (how many, not sure) are there lots of little inverters or do you add the DC volts up and convert at some high voltage?

If there's significant power you'd want to stack cells to make higher voltage.
Power is volts X amps and it's advantageous to not have to handle large currents, the wires are just too bulky.,

I have zero experience with fuel cells. Have you a link to the ones that sparked your interest?

 

[Sclerostin]

Yes, I can guess the general idea but I was thinking about at the problems of Solar e' on a large scale. Companies use battery storage which is very costly and then still has to match ("instantaneously") Grid needs, needing another costly step, such as a synchronous motor. So an extra (costly) system is needed. I'm trying to see if H2 power has the same problem. You could store H2 in "gasometers" as was done years ago (CO +H2) but if its difficult to convert to grid voltage, its not an easy solution.

Just for general knowledge.

 

[Sclerostin]

The Siemens link is very easy to understand: thanks.

 

[russ_watters]

Yes, I can guess the general idea but I was thinking about at the problems of Solar e' on a large scale. Companies use battery storage which is very costly and then still has to match ("instantaneously") Grid needs, needing another costly step, such as a synchronous motor. So an extra (costly) system is needed. I'm trying to see if H2 power has the same problem.

Hydrogen is worse; more expensive, less efficient.

If you google or PF search "hydrogen economy" you'll find articles and threads from 10-15 years ago predicting it was on the way and newer articles and threads discussing why the idea died.

In short, fuel cells are inherently expensive and inefficient and in the meantime lithium batteries have gotten much cheaper, giving us Teslas and drones.

 

[anorlunda]

Some fuel cells operate on natural gas. They do not necessarily need pure hydrogen.

The schools in Ballston Spa, NY provide their own electric power using two piston engines converted to natural gas, and driving electric generators. In that case, I think that fuel cells must compete with those piston engines at the small scale. At the utility level, they need to compete with gas turbines and combined cycle gas-powered plants.

My presumption is that cell lifetime, not fuel, not efficiency is holding them back.

 

[berkeman]

Thread closed temporarily for Moderation.

 

[berkeman]

OP's question has been answered. After some post deletions, the thread will remain closed. Thanks for the helpful replies.