Create accountLogin

Recent searches

No recent searches

Search options

Only available when logged in.
toot.cat is one of the many independent Mastodon servers you can use to participate in the fediverse.
On the internet, everyone knows you're a cat — and that's totally okay.

Administered by:

Server stats:

488
active users

toot.cat: AboutProfiles directoryPrivacy policy

Mastodon: AboutGet the appKeyboard shortcutsView source codev4.4.0-alpha.4+glitch.14353f21c

Public

@tindall@cybre.space Energy budgets are pretty well-established. The US DOE produces its sankey diagrams (energy flow charts) through the LLNL, there are similar data for the IEA and elsewhere. Pick up virtually any book on energy or climate (IPCC) and you'll find a breakdown. These aren't mysteries.

Here's the 2020 LLNL / US chart.

flowcharts.llnl.gov/content/as

Interesting, straight off the top: the usage is once again well below 100 quad (quadrillion BTUs, thanks, standard system, a/k/a 105 billion billion joules, ~30k TWh, 17 billion barrel oil equivalent (bboe), 2.5 billion tonoil equivalent (btoe), 3.6 toncoal equivalent (btce).

If you look through the archive site, you'll find a set of projections from about 1975, projecting use forward to 1980 and 1990, as well as back decadally to 1950. Looking at those, thirty years ago the US should have been using far more energy than it is now, if 1950--1975 trends had continued.

flowcharts.llnl.gov/content/en

flowcharts.llnl.gov/archive.ht

1/

Public

@tindall@cybre.space All of that out of the way ...

The biggest use is ... industry, just edging out transportation (this was a surpriise), though veyr roughly you can divide energy use into thirds: transport, residential & commercial, and industry. There's also electrical generation, but that's simply an energy mode that's then allocated to end use.

There's a lot of focus on the "rejected energy" element, though IMO that's largely misguided. Most of that is based on theoretical and practial efficiencies, e.g., thermal motive energy (including tranport and electrical generation) runs at ~30--40% efficiency simply due to Carnot process. Unless the energy cycle itself is fundamentally changed, that's a given. There are efficiency gains possible, but it's fairly modest.

2/

@tindall@cybre.space
The major modifiable elements are transport and discretionary energy use. Transport (about 25% of net energy) is about 70% private passenger, 30% bulk cargo. Modes matter.

The biggest determinant of transportation energy use isn't vehicles or modes, it's land use.

If you spread things out, you need to move things around. A lot. Density also enables and disables numerous transportation modes. Most especially, high-capacity transit (heavy rail, high-speed rail, light rail, busses, trollycar / trollybus) all rely on high concentrations of residences, workplaces, commerce, and industry.

3/

·Public
1boost·0favorites
Public

@tindall@cybre.space And some modes are notably efficient. Ships and trains, by units of mass*distance/fuel are phenomenally efficient, up to 500 ton-miles/gallon for rail, perhaps double that for marine or canal shipping.

Trucks are much less efficient but far more flexible. And passenger cars are comparatively abysmal.

With bulk cargo, scale again matters. Endpoint distribution is hard (the last-mile problem). Rural delivery is similarly difficult (package-delivery services love the high-margin urban areas, but defer to national postal services for rural delivery, typical of any networked-distribution system: mail, electricity, POTS telephony, cellular telephony, broadband internet, retail chains, ...).

The biggest impact of the automobile has been on land-use patterns.

4/

Public

@tindall@cybre.space Other energy uses also derive from land-use.

With denser urban regions:

  • Per-unit heating and cooling costs are decreased (shared walls -> reduced heating/cooling loads.
  • Communal foodservice. Whether informal or commercial foodservice, meal prep and production occurs at scale. (The low-ooccupancy unit, highly-appointed kitchen is a recent novelty. Earlier times had larger multi-generational houses, rooming-homes, public houses (pubs) for food, village ovens, etc.) The space allocated in residences to food storage, prep, cooking, and cleanup is substantial.
  • Infrastructural efficiencies. discusses this aspect at length.

5/

Public

@tindall@cybre.space Density isn't everything, and there are many other elements to be considered. But as a single point of intervention, it's probably the least-cost / highest-benefit route.

Vastly more effective than pushing the individual-responsibility canard.

6/end/

SearchLive feeds
About