5 ms·

The most interesting national electricity grid has to be Japan's, with two completely different networks operating at different frequencies, and connected by HV

by nickff 6y ago

The most interesting national electricity grid has to be Japan's, with two completely different networks operating at different frequencies, and connected by HVDC. https://en.wikipedia.org/wiki/Electricity_sector_in_Japan https://en.wikipedia.org/wiki/Electricity_sector_in_Japan

fomine3 6y ago
That's still pain. When I (live in 50Hz area) buy cheap dehumidifier, I get lower performance due to lower frequency.
- MisterTea 6y ago
  AC motor speed is frequency dependent so your dehumidifier compressor and fan motors are running slower and producing less mechanical power.
fomine3 6y ago
I come up with a hypothesis: Japan's divided frequency situation made Japanese electric manufacturers to invent inverter for electrics (example: air conditioners, microwave, refrigerators). Inverter primary makes electrics controllable efficiently, also they can ship same product (same performance) for both 50/60Hz area in Japan.
- fireattack 6y ago
  Any "evidence" (or anything substantial) about your hypothesis? Like, did Japanese companies actually invent inverters, or are inverter air conditioners more common in Japan compared to other countries?
  - fomine3 6y ago
    Sorry for bad English, "develop" would be better word than "invent". AFAIK Daikin argues that Inverter Air conditioner is very popular in Japan compared to other developed countries. In Japan, mini-split type a/c is common and almost all producs are runned by inverter compressor (except very cheap one but almost no one buy it). Here's Daikin's argument (japanese). Green is % of inverter and Japan is 100%. https://www.daikin.co.jp/csr/information/lecture/act01.html https://www.daikin.co.jp/csr/information/lecture/act01.html https://www.daikin.co.jp/csr/information/lecture/images/act01_image02.gif https://www.daikin.co.jp/csr/information/lecture/images/act0... It seems that world's first inverter a/c is by Toshiba. https://toshiba-mirai-kagakukan.jp/en/learn/history/ichigoki/1981aircon/index.htm https://toshiba-mirai-kagakukan.jp/en/learn/history/ichigoki...
    - fireattack 6y ago
      Thanks for the links! I do found that inverter AC seem more popular in East Asian countries. But then again, they don't use central air conditioning in residential as much as the US do, so probably not an apple to apple comparison.
    - EricE 6y ago
      My parents have an inverter mini-split. It’s amazingly effective at dehumidification. If I ever have to change out one of my AC units I will probably go with a multi-zone mini split. Being able to condition only the rooms that are in use and the super effective dehumidification the systems offer are a significant upgrade over traditional ducted AC systems. Heat pumps on mini splits tend to be far more effective too.
tibbydudeza 6y ago
One region used American and the other one German sourced generators ... like NTSC vs PAL :).
danw1979 6y ago
"The total transmission capacity between the two grids is 1.2 GW" That's a tiny amount for an industrialised nation of 125 million people, considering that the border between the grids cuts right between Tokyo and the other western centres of population. I think this, and the nuclear power shutdown, lend some context to Japan’s push for a hydrogen economy.
- tlamponi 6y ago
  That's only the inter-grid exchange capability, over AC1 <-> DC <-> AC2 transformation, not the total one If you read the article, the US has about the same inter-grid exchange capability for the west and east coast grids. Japan has alone over 50 GW of solarpower, and that's only a small share of their energy mix. They produced 1009 TWh in 2015, that'd be an average of 117.95 GW, and usage is seldom average, but with daily peaks. I'd take an educated guess and say their nets can handle multiple hundreds of GW to up to a TW just fine..
  - suifbwish 6y ago
    Oh yeah.. you can definitely tell they have electricity from space at night

by nickff 6y ago

fomine3 6y ago

That's still pain. When I (live in 50Hz area) buy cheap dehumidifier, I get lower performance due to lower frequency.

MisterTea 6y ago
AC motor speed is frequency dependent so your dehumidifier compressor and fan motors are running slower and producing less mechanical power.

fomine3 6y ago

I come up with a hypothesis: Japan's divided frequency situation made Japanese electric manufacturers to invent inverter for electrics (example: air conditioners, microwave, refrigerators). Inverter primary makes electrics controllable efficiently, also they can ship same product (same performance) for both 50/60Hz area in Japan.

fireattack 6y ago
Any "evidence" (or anything substantial) about your hypothesis? Like, did Japanese companies actually invent inverters, or are inverter air conditioners more common in Japan compared to other countries?
- fomine3 6y ago
  Sorry for bad English, "develop" would be better word than "invent". AFAIK Daikin argues that Inverter Air conditioner is very popular in Japan compared to other developed countries. In Japan, mini-split type a/c is common and almost all producs are runned by inverter compressor (except very cheap one but almost no one buy it). Here's Daikin's argument (japanese). Green is % of inverter and Japan is 100%. https://www.daikin.co.jp/csr/information/lecture/act01.html https://www.daikin.co.jp/csr/information/lecture/act01.html https://www.daikin.co.jp/csr/information/lecture/images/act01_image02.gif https://www.daikin.co.jp/csr/information/lecture/images/act0... It seems that world's first inverter a/c is by Toshiba. https://toshiba-mirai-kagakukan.jp/en/learn/history/ichigoki/1981aircon/index.htm https://toshiba-mirai-kagakukan.jp/en/learn/history/ichigoki...
  - fireattack 6y ago
    Thanks for the links! I do found that inverter AC seem more popular in East Asian countries. But then again, they don't use central air conditioning in residential as much as the US do, so probably not an apple to apple comparison.
  - EricE 6y ago
    My parents have an inverter mini-split. It’s amazingly effective at dehumidification. If I ever have to change out one of my AC units I will probably go with a multi-zone mini split. Being able to condition only the rooms that are in use and the super effective dehumidification the systems offer are a significant upgrade over traditional ducted AC systems. Heat pumps on mini splits tend to be far more effective too.

tibbydudeza 6y ago

One region used American and the other one German sourced generators ... like NTSC vs PAL :).

danw1979 6y ago

"The total transmission capacity between the two grids is 1.2 GW" That's a tiny amount for an industrialised nation of 125 million people, considering that the border between the grids cuts right between Tokyo and the other western centres of population. I think this, and the nuclear power shutdown, lend some context to Japan’s push for a hydrogen economy.

tlamponi 6y ago
That's only the inter-grid exchange capability, over AC1 <-> DC <-> AC2 transformation, not the total one If you read the article, the US has about the same inter-grid exchange capability for the west and east coast grids. Japan has alone over 50 GW of solarpower, and that's only a small share of their energy mix. They produced 1009 TWh in 2015, that'd be an average of 117.95 GW, and usage is seldom average, but with daily peaks. I'd take an educated guess and say their nets can handle multiple hundreds of GW to up to a TW just fine..
- suifbwish 6y ago
  Oh yeah.. you can definitely tell they have electricity from space at night