3 ms·

Circumference of the earth 40,000km Power loss .5-1.1% for 160km If we assume 200km has 1% power loss then 20,000km is around 63% power loss.

by ximeng 8y ago

mrfusion 8y ago
He said super conductor. So no losses. Jus the cooling costs but we could insulate it really well. High voltage dc might be another option to minimize losses.
- craftyguy 8y ago
  > High voltage dc I thought that was proven over a hundred years ago to not be an efficient way to carry electricity over long distances.. did something change recently?
  - ahartmetz 8y ago
    Low voltage DC was bad. It had to be low voltage because there were only motor-generator, expensive and inefficient transformers for DC. Today, all conversions can be done in solid-state electronics. DC to AC and DC to different voltage DC are still more expensive and lossy than AC-AC, but sometimes the best option in a given situation.
    - craftyguy 8y ago
      > DC to AC and DC to different voltage DC are still more expensive and lossy than AC-AC, but sometimes the best option in a given situation. Ok, what's a situation involving long distance transmission where DC-AC or DC-DC is best?
      - cbdumas 8y ago
        Wikipedia has a nice list[1] of existing and upcoming projects where transmission engineers judged HVDC to be the best solution. [1] https://en.wikipedia.org/wiki/List_of_HVDC_projects https://en.wikipedia.org/wiki/List_of_HVDC_projects
      - ahartmetz 8y ago
        DC-AC and DC-DC are just conversions - conversions used to be the problem with DC for distribution. For HVDC in an AC net you need AC-DC (not much of a problem) and DC-AC (more difficult, solved with only minor losses today). The advantages of DC transmission are flexibility (can have power flow either way between any unsynchronized AC nets) and lower transmission losses per distance. The details are all on Wikipedia.
magicalhippo 8y ago
According to Wikipedia HVDC lines are <3% per 1000km[1]. So that leads to ~46% loss for 20000km. If they could get it down to 1% per 1000 km, then it's only ~18% (for some value of only). [1]: https://en.wikipedia.org/wiki/High-voltage_direct_current#Advantages https://en.wikipedia.org/wiki/High-voltage_direct_current#Ad...

Circumference of the earth 40,000km Power loss .5-1.1% for 160km If we assume 200km has 1% power loss then 20,000km is around 63% power loss.

by ximeng 8y ago

Circumference of the earth 40,000km Power loss .5-1.1% for 160km If we assume 200km has 1% power loss then 20,000km is around 63% power loss.

mrfusion 8y ago

He said super conductor. So no losses. Jus the cooling costs but we could insulate it really well. High voltage dc might be another option to minimize losses.

craftyguy 8y ago
> High voltage dc I thought that was proven over a hundred years ago to not be an efficient way to carry electricity over long distances.. did something change recently?
- ahartmetz 8y ago
  Low voltage DC was bad. It had to be low voltage because there were only motor-generator, expensive and inefficient transformers for DC. Today, all conversions can be done in solid-state electronics. DC to AC and DC to different voltage DC are still more expensive and lossy than AC-AC, but sometimes the best option in a given situation.
  - craftyguy 8y ago
    > DC to AC and DC to different voltage DC are still more expensive and lossy than AC-AC, but sometimes the best option in a given situation. Ok, what's a situation involving long distance transmission where DC-AC or DC-DC is best?
    - cbdumas 8y ago
      Wikipedia has a nice list[1] of existing and upcoming projects where transmission engineers judged HVDC to be the best solution. [1] https://en.wikipedia.org/wiki/List_of_HVDC_projects https://en.wikipedia.org/wiki/List_of_HVDC_projects
    - ahartmetz 8y ago
      DC-AC and DC-DC are just conversions - conversions used to be the problem with DC for distribution. For HVDC in an AC net you need AC-DC (not much of a problem) and DC-AC (more difficult, solved with only minor losses today). The advantages of DC transmission are flexibility (can have power flow either way between any unsynchronized AC nets) and lower transmission losses per distance. The details are all on Wikipedia.

magicalhippo 8y ago

According to Wikipedia HVDC lines are <3% per 1000km[1]. So that leads to ~46% loss for 20000km. If they could get it down to 1% per 1000 km, then it's only ~18% (for some value of only). [1]: https://en.wikipedia.org/wiki/High-voltage_direct_current#Advantages https://en.wikipedia.org/wiki/High-voltage_direct_current#Ad...