So first off my opinion
Hydrogen is one of those technologies I thought I understood.
You have hydrogen. You burn it. You get energy.
Easy!
On my walk home from work Nottingham Uni have “started building Nottingham Hydrogen Propulsion Systems Lab”
So then I start looking into it and realise that hydrogen isn’t really an energy source in the same way that gas, coal, wind or solar are.
We have to make the hydrogen first.
That changes the question quite a bit.
Where did the energy come from to make it? How much did we lose making it? How are we going to store it? How do we move it? Then finally, what are we actually going to use it for?
Suddenly hydrogen becomes much more interesting.
So what actually is hydrogen power?
Hydrogen is an energy carrier.
That’s an important distinction.
We can use electricity to split water into hydrogen and oxygen using electrolysis.
The hydrogen can then be stored and used later.
That might mean burning it in something similar to a gas turbine, or passing it through a fuel cell to produce electricity.
So potentially:
Electricity → Hydrogen → Storage → Electricity
Straight away my data-engineer brain sees a problem.
Every arrow represents a process.
Every process has efficiency losses.
If I’ve already got electricity, why don’t I just use the electricity?
And that seems to be one of the big questions around hydrogen.
The colours of hydrogen
Something else I didn’t appreciate before looking into it is that people talk about hydrogen using colours.
Grey Hydrogen
Usually produced from natural gas.
It’s hydrogen, but producing it releases CO2.
Blue Hydrogen
Similar process, except an attempt is made to capture the resulting carbon.
Which immediately links hydrogen to another thing I’ve been looking at — Carbon Capture and Storage.
Green Hydrogen
Produced using electrolysis powered by renewable electricity.
This is probably what most people imagine when someone talks about clean hydrogen.
There are more colours, because apparently the energy industry wasn’t satisfied with three!
But those three already demonstrate something important.
Saying “hydrogen” doesn’t tell you much about its environmental impact.
You need to know how it was produced.
Where I think it gets interesting
Renewables have a problem.
Sometimes we have too little electricity.
Sometimes we have too much.
A wind turbine producing electricity nobody currently needs isn’t particularly useful if that electricity has nowhere to go.
But what if that excess electricity produces hydrogen?
Now we’ve potentially turned electricity that might otherwise have been curtailed into something we can store.
And unlike a battery, you could potentially store a very large amount of hydrogen for a long time.
That’s where hydrogen starts making more sense to me.
Not necessarily:
Let’s make all our electricity from hydrogen.
But perhaps:
We have energy available now that we don’t need until later. Can hydrogen move that energy through time?
That’s a much more interesting question.
Then there is the data
This is where I start seeing the interesting bit for people like me.
When should the electrolyser run?
What’s the electricity price?
What’s renewable generation doing?
What’s the weather forecast?
How full is the hydrogen storage?
What’s the expected demand?
What’s the efficiency of the electrolyser today compared with six months ago?
What condition is the equipment in?
You potentially have generation data, market data, weather data, storage data and engineering condition data all influencing the decision.
That’s quite a data problem.
And it’s exactly why I like understanding the engineering behind the numbers.
If all I see is an electrolyser consuming 20 MW, that’s one thing.
If I understand why it’s consuming 20 MW at that particular moment, the data starts telling a much bigger story.
So where is my head at?
I’m interested in hydrogen, but I’m not convinced by the idea that it should be used everywhere.
Turning electricity into hydrogen and then back into electricity introduces losses that batteries don’t have to the same extent.
But batteries and hydrogen aren’t necessarily trying to solve exactly the same problem.
A battery might be brilliant at moving energy from lunchtime to teatime.
Hydrogen might potentially help move energy much further.
And there are industrial processes where simply sticking a massive battery on something isn’t the answer anyway.
So perhaps the mistake is asking:
“Will hydrogen replace batteries?”
Maybe the better question is:
“Which energy storage problem are we actually trying to solve?”
That’s where my head is at the moment.
Gareth Winterman