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Posted by 0sake_rs 10 hours ago

Sustainable energy without the hot air (2008)(www.withouthotair.com)
127 points | 68 commentspage 2
abetusk 3 hours ago|
I find it interesting that the average energy consumption of a person (or household?) is roughly 30kWh/day and the energy usage of a car is roughly 40kWh/day. I wonder if it's some kind of truism that our transportation needs roughly equal our energy needs.

I'd be interested to know if that's just a coincidence or whether there's an underlying reason.

tomjakubowski 3 hours ago||
A person riding a bicycle expends an order of magnitude less energy than does a car ferrying the same person the same distance. So I don't think this really holds.

For comparison: at 50 MPG, traveling one mile by car uses 0.02 gallons of gasoline. This is about 675 Wh of energy or 580 kcal. Travel by bicycle for a ~180lb person is about 60 kcal per mile.

abcd_f 3 hours ago||
And a straight angle is just 10 degrees away from the water's boiling point. Might be something in it too :)
peri-cl 8 hours ago||
The author is coincidentally the author of a (free-to-read) information theory book which is also popular on HN,

https://news.ycombinator.com/item?id=34618613 ("Information Theory, Inference, and Learning Algorithms (2003) (inference.org.uk)")

myrmidon 6 hours ago||
I knew I had seen the name before.

That book significantly decreased my appreciation of our statistics professor @uni, because it presented the same topics in a much more interesting and digestible way. Can recommend.

That book and Gershgorin circles (to work around all the stupid, constructed 3x3 matrix eigenvalue problems that they love to sprinkle into literally every early stem exam) helped more in university than anything else.

esafak 8 hours ago||
The late author.
ml_basics 6 hours ago||
The untimely death of David MacKay was a tragic loss for the scientific community. It's astonishing that he wrote the textbook on information theory for the ML community as well as his contributions to rational discussion about energy policy.

He had a direct personal impact on my life since my introduction to ML came from video recordings of his lectures on ML and information theory. I am grateful to have learned from such an excellent teacher. Like a Feynman of our times.

PaulDavisThe1st 3 hours ago||
The publisher of this book (and the series) was my second programming mentor, and the person who introduced me to the GNU Project and libre software in general, back in 1986/87. I call him Dr. X and he calls me "The Professor".
bencord0 4 hours ago||
RIP Professor MacKay

I remember him giving this talk to my physics class when I was in University. It was so inspirational to me that the UK just might be able to go 100% renewable.

From what I remember, the calculation worked out how we could do it all with Solar. I don't think he quite saw how close we are to achieving the goal, not with Solar, but with Wind within the next decade.

danrecht 8 hours ago||
David McKay was a great public speaker as well: https://youtu.be/GFosQtEqzSE?si=Gyrcep1VDae6xDo1&t=110
rekabis 1 hour ago||
Holy 1997 web design, Batman.
citizenfishy 7 hours ago||
Lings Cars!
perennialreport 9 hours ago|
Worth reading even with the dated numbers. MacKay's lasting contribution isn't any specific forecast - it's the discipline of expressing everything in the same units (kWh per day per person), which makes energy arguments commensurable instead of vibes-based. Once you've internalized that, most energy coverage in the media starts reading like category errors. The specific figures have moved - solar costs, EV adoption, heat pump uptake - but the arithmetic habit hasn't aged at all.
bryanlarsen 8 hours ago|
kWh of work and kWh of primary energy are two different measurements with the same unit. Mixing the two is invalid.
zahlman 5 hours ago||
I'm pretty sure you're replying to an LLM bot.