AukeHoekstra Profile picture
Dec 12, 2021 8 tweets 4 min read Read on X
In my (Dutch) newspaper @trouw, mobility historian Vincent Vinne proclaims electric cars are unsustainable because they have lots of power and can drive fast.

Let me explain (again) why these things are actually beside the point for electric cars.
trouw.nl/opinie/waarom-…
Basically it's very simple: regular combustion engines get less efficient when they don't perform at their optimal power number of rotations per minute. You can see this in a BSFC plot.
On this map optimum is >250 g/kWh but it can increase to 475 g/kwh.
x-engineer.org/brake-specific…
So this means that a powerful engine (with a high top speed) is usually used at an optimal of say 70% of max power but only at 10% which then doubles energy use.

So historically speaking, mobility historian Vincent Vinnes is right. More power and topspeed is energy inefficient!
For a combustion engine in a practical car 35% optimal efficiency is pretty good. In the city it can easily drop to 10% or so: >200% more fuel use.

For EVs it works similarly but the impact is small. E.g. efficiency drops from 92+% to 86%: 7% more energy.
x-engineer.org/electric-vehic…
To make an issue out of the marginal extra energy use because of their top speed and acceleration betrays a fossil mindset.

(You could argue fast cars are less safe and driving at higher speeds does use more energy by the way. But these are very different issues.)
This doesn't mean electric vehicles are optimally sustainable! By making them larger and heavier and by not sharing them we use much more energy and material than is optimal!

So the Dutch head of state travels a lot more sustainably!
But let's put the focus where it belongs. When you want sustainable transportation, forget about making electric vehicles less powerful and slower (it hardly helps) and focus on making them smaller, lighter and shared.
/end
This should have been: an engine performs optimally at around 70% so a powerful engine that is usually used at much lower power (say 10%) will use twice as much energy as optimally possible in daily use.

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More from @AukeHoekstra

Jun 17
The official report on the blackout in Spain and Portugal is just released. I'll give a quick summary of findings and provide some additional info.

TL;DR
conventional power plants didn't control the voltage as planned
over-voltage caused renewables to turn off as required
The report (of which only press reports are available) points the finger to

1 conventional backup plant taken offline for maintenance without replacement being arranged

9 other conventional backup plants, of which every one had a degree of non-compliance
uk.news.yahoo.com/spain-reveals-…
Renewables also had a role: "tension was very high and sustained, causing the disconnection of generators".


An inside source tells me the voltage went above 110% in many places and solar was required to switch off, which meant 8GW was lost all at once.elpais.com/economia/2025-…
Read 5 tweets
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

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