AukeHoekstra Profile picture
Oct 16, 2021 8 tweets 3 min read Read on X
I agree there is a place for hydrogen in mobility.
I just think it's probably a very small place.

I think this piece of @Toyota chief scientist Gill Pratt is heavily skewed toward hydrogen in order to make it seem more important. Let me show you.
medium.com/toyotaresearch…
Charging speed is limited by the so called C rate of battery cells.
Simply put: larger vehicles with more cells can stomach bigger chargers.
So big trucks will charge just as fast as small cars.

And of course 90% of charging is done while parked so speed isn't an issue there.
I remember how better place imagined that we would swap batteries to overcome charging time. These days are gone and 60 minutes is simply BS. I think in 2030, new EVs coming out can charge 80% of their range within ten minutes. For something you do occasionally that's a non issue
What also bugs me is that H2 proponents compare the battery weight of an entire lithium battery with the weight of unpackaged hydrogen. But it's the hydrogen tank that dominates the weight, which is one of the reasons fuel cell vehicles are currently not (much) lighter.
Don't get me wrong: if you need to be able to travel very LONG distances without the ability to replenish energy, hydrogen has a clear advantage, esp. liquified. That's why it's great for long distance ships and planes. But required RANGE is much more important than vehicle size.
Also, the size comparison is very deceptive. Batteries can be packaged anywhere you like while lowering center of gravity. And batteries are continuing to get more compact.

Rounded H2 tanks take away more practical space than just their content.

Again a very skewed comparison.
Also, if you have to compress hydrogen you probably won't get 70% efficiency.

More importantly, fuel cells are about 60% efficient. If you also include motor losses you are at 55% or so. So the losses are much bigger.

The 90% of EVs is correct though.
So I agree we should not demonize hydrogen cars. If they give battery electric vehicles competition I'm all for it because both can be very good for the climate and there is a place for both.

But let's not skew the facts to make hydrogen seem more attractive than it is.

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More from @AukeHoekstra

Jun 10
Just made a visualization for myself about the unprecedented growth in solar that I thought I might share.

From 1880 to 1950 all electricity came from fossil+hydro. Then nuclear briefly grew with market share increasing with up to 1% per year in 1985.

Now solar takes over. Image
I've described in more detail in a substack post:

There's more info on each picture there.aukehoekstra.substack.com/p/the-coming-s…
I made this picture because I think you forget what is happening when you look at total final energy. Renewables seem so tiny! Image
Read 8 tweets
Jun 9
I see this a lot:

Conservatives who *just know* that nuclear is better than solar and thus blame their favorite scapegoat *the government* for solar doing better.

But in reality it's the opposite: the market likes solar so much that not even the government can save nuclear.
I guess Andre's attention for me is due to my being irritated at his fact free diatribes of pseudo-scientific nonsense:


So now he sees reacting to me as a way to get attention?
And I'm reacting again, so maybe I'm being duped?
Anyhow...
Let's start with some quantifiable facts. (Things this conservative armchair energy philosopher is allergic to.)
First thing we notice is that solar and wind are clearly surpassing nuclear (though the new leadership of the department of energy denies it).
Image
Read 19 tweets
May 18
Many people think solar and wind won't be able to keep the grid stable because they lack "inertia".

I think solar, wind and batteries will do a BETTER job and I think you can explain it thus:
- the old grid is a record player
- the new grid a digital player
🧵 Image
If you play vinyl records, the rotating mass of the turntable is used to keep the speed steady. This leads some vinyl enthusiasts to seek more mass because that will keep things more steady.

This turntable by Excel audio attaches a separate mass. (Overkill but makes my point.) Image
In the same way the inertia in the rotors of current power plants helps the grid to keep a steady 50 Hz (in e.g. Europe) or 60 Hz (in e.g. the US) frequency.

These machines turn a heavy copper coil wound around a heavy iron core and this helps keep the grid frequency steady. Image
Read 21 tweets
Aug 13, 2024
Great to see more and more attention for flexible grid pricing.

We must say goodbye to the "copper plate" that offers free power everywhere and every time. It's hideously expensive and outdated.

What we need is smart flexibility.
🧵
The underlying reason is that the costs of different components of the energy system changed:

Some remained high (e.g. pylons, fossil & nuclear)

Some plummeted (e.g. solar, wind, batteries, EVs & inverters)

Some became possible at all (e.g. measuring & steering in real time)
So now we should make good use of these new, clean, abundant and affordable options, even if it means doing things a bit differently than before.

So what should we do different regarding grid congestion pricing?
Read 20 tweets
Jul 28, 2024
Some are angry about the "anti-Christian depiction of the last supper" at the Olympic Opening ceremony. (@elonmusk and @realDonaldTrump among others)

A Dutch art historian explains it's not the last supper but a Dutch painting of the Olympic gods.
And I explain what I loved.
🧵
Image
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Original Dutch thread here. I just translated it.


@WSchoonenberg shows that the "tableau vivant" (living painting) is depicting "The Feast of the Gods" by Jan van Bijlert, from 1635.
Image
The heathen Gods have gathered on mount Olympus for a feast. Sun god Apollo is recognizable by his halo, Bacchus (Dionysus) by the grapes, Neptune (Poseidon) by his trident, Diana (Artemis) by the moon, Venus (Aphrodite) by Cupid.


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Read 24 tweets
Jul 9, 2024
With new batteries solar and wind are not only faster and cleaner, but also cheaper.

I'm estimating:
$0.08/kWh for PV+batteries
$0.07/kWh for wind+batteries

@skorusARK gives a good overview of current wisdom, but strongly declining battery prices change EVERYTHING
Image
I've recently written about how I was surprised I missed the enormous consequences of price reductions in batteries.

LFP cells are now $50/kWh and last 10 000 cycles.
That's $0.005 per kWh.

Say we double that to pack the cells and you are at $0.01/kWh.aukehoekstra.substack.com/p/batteries-ho…
If you add batteries to solar PV, not all energy has to flow through batteries. But let's keep it at $0.01 and add that to the price of solar. That makes PV (and wind) SUPER cheap!

Batteries must be discounted more quickly you say?
Read 10 tweets

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