Sustainable Energy - Without the Hot Air

What Hacker News says

1. leonidasrupApr 2026
   You are both right and wrong at the same time.

   Long time ago when Siemens in Germany was still building nuclear power plants, I was working in the nuclear power plant engineering department. After the year 2022 when the Russia invaded Ukraine, the gas shortages and the following costs hikes renewed my interest energy sector. Why didn't German reverse it's anti-nuclear stance, even with war in Europe?

   Was is the general lack of knowledge of physical, technological and economical aspects of energy, both in German population and decision makers?

   The political aspect became clearer after reading "Akte Atomausstieg" by Daniel Gräber.

   https://www.perlentaucher.de/buch/daniel-graeber/akte-atomau...

   Little bit of money from oil and gas industry always helps.

   https://correctiv.org/en/latest-stories/2022/10/07/gazprom-l...

   https://www.politico.eu/article/robert-habeck-germany-qatar-...

   I think solar and wind are interesting technologies, (solar almost magical - turning photons of light inside thin layer of doped silicon into electrons) but by itself insufficient to power modern world. They are intermittent, weather dependent and low density. Yes the sun and wind come free from Sun, the machines that convert the energy, store it and distribute it are not. Minerals have to be mined, machines build, transported, installed and then disposed off.

   Recommended reading:

   "Sustainable Energy – Without the Hot Air" by Sir David John Cameron MacKay

   https://withouthotair.com/

   Books by Vaclav Smil:

   Energy and Civilization: A History

   Energy Transitions: Global and National Perspectives

   How the World Really Works

   "Why Nuclear Power Has Been A Flop" - The Gordian Knot of the 21st Century

   https://gordianknotbook.com/

   There are still big hydrocarbon reserves, gas/oil for atleast 100 years, coal 200 years, at current consumption rates. I fear that, if we don't use the only carbon free high density energy source and cling our hopes to the mirage of renewables, we will transform our atmosphere to hell.

   When even the oil and gas giants advertise for renewables, you know that renewables will never replace fossil fuels.

   "gas the perfect partner for renewable energies"

   https://totalenergies.com/news/news/natural-gas-integral-par...

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2. philipkglassMar 2026
   The author Hannah Ritchie works on Our World In Data and also publishes the fantastic Sustainability by Numbers substack. It's in the same vein as the late, great David MacKay's Sustainable Energy Without the Hot Air.

   This tool has its own recent substack post. See the comments too, especially the one by Chris Preist that contextualizes the energy usage of streaming video (a topic that has also been discussed on HN before).

   https://hannahritchie.substack.com/p/does-that-use-a-lot-of

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3. thijsonJul 2025
   I've found this web site to be informative about what it would take to go fully renewable:

   https://www.withouthotair.com/

   A lot of the calculations are back of the envelope, but I guess provide a ballpark estimate.

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4. ben_wJul 2024
   Indeed.

   I was briefly tempted to create a globalised version of David MacKay's classic "Sustainable Energy - without the hot air" under the title "How to save the world and get rich trying", but (a) there's no point because all the business people already noticed, and (b) someone else thought of that name before I got around to it and used it for a series of videos.

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5. schiffernMay 2024

     >A guy on one of these doing the minimum speed.
   

   Counterintuitively, that probably makes it harder.

   With any wing, the faster you go in level flight the less drag is caused by lift. This strange fact is because moving a large amount of fluid slowly is more efficient than moving a small amount of fluid fast, and a faster wing can interact with more fluid mass per second ("m dot").

   https://en.wikipedia.org/wiki/Lift-induced_drag#Calculation_...

   Since skin drag increases with speed, adding these two drag curves together forms a 'valley' in the overall speed-vs-drag curve. Going slower or faster than this ideal speed will result in increased energy per mile.

   The math is better explained in David MacKay's brilliant ebook, 'Sustainable Energy Without the Hot Air.'

   https://www.withouthotair.com/cC/page_269.shtml

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6. joeyoJan 2024
   David MacKay discusses this in Sustainable Energy Without the Hot Air. He concludes that, while it's on first glance appealing to want to use waste heat from power generation, heat pumps are strictly superior to combined heat and power except for in a few specialized circumstances (e.g. industrial uses that require high temperatures). The book is fifteen years old now, so I suspect the math even more strongly favors heat pumps than when it was published.

   See the section, "Heat pumps, compared with combined heat and power": https://www.withouthotair.com/c21/page_147.shtml

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