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Is anyone aware of what the maximum economically feasible transmission distance is for power lines? I ask as they specifically cite the need for transmission f

Is anyone aware of what the maximum economically feasible transmission distance is for power lines? I ask as they specifically cite the need for transmission from west to east (to power hungry cities). I have also wondered how efficient can those transmission towers be. Anyone have any knowledge? Is it reasonable to expect power to be generated on one side of China, and have it used on the other side? Edit: qualified maximum distance to economically feasible maximum distance

adrianN 7y ago
This article here contains some helpful information: https://en.wikipedia.org/wiki/HVDC https://en.wikipedia.org/wiki/HVDC
- std_throwaway 7y ago
  "HVDC transmission losses are quoted as less than 3% per 1,000 km"
- snaky 7y ago
  > China is the global test bed for ultra-high voltage (UHV) transmission lines, a technology that can carry electricity across vast distances with much greater efficiency than the high voltage lines that you’re probably used to seeing. > Since 2006, it’s built 19 of these multi-billion-dollar lines, stretching almost 30,000 kilometres and supplying 4% of national electricity demand. For comparison, no other country has a single UHV line in full commercial operation. > But China’s enthusiasm for UHV is waning. The technology is beset by conflicts of interest between grid companies and central and local governments. The lines themselves are underperforming, and more recent projects are coming online amid a period of electricity generation overcapacity. > This means that approvals for new lines have slowed, and grid companies are unlikely to meet their targets for new ones. https://www.chinadialogue.net/article/show/single/en/10376-Sparks-fly-over-ultra-high-voltage-power-lines https://www.chinadialogue.net/article/show/single/en/10376-S...
- deleted 7y ago
  [deleted]
- SECProto 7y ago
  even more helpful info here: https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity_transmission_in_China https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity...
benj111 7y ago
There isn't really a hard limit, the longer the cable, the bigger the losses. You can mitigate that somewhat by increasing the voltage, which is what they're doing. So basically the distance is determined by economics. If China could install solar and cables cheaply enough, then they could compete with domestic European and American electricity. I find that doubtful though.
exabrial 7y ago
Hvdc can go a very very long way; thousands of miles economically. 500kv a.c. @ 60z starts to become impractical above 1000 miles if I recall correctly. I'll not sure how 50hz power is more or less affected on transmission, but it requires larger transformers, making each conversion step more expensive from a fixed cost perspective. Edit: I didn't recall correctly, looks like hvac is not very effective above 700mi, and in underground and underwater applications, far less.
- cogman10 7y ago
  HVDC has a few benefits. First, because you need to turn it into AC eventually and it doesn't have a frequency, it makes connecting grids a snap. You can hook a 50Hz grid to a 60Hz grid or even just two 60Hz grids with different phases. The lack of alternating means you can bury the line. HVAC will lose power when it is close to conductors (ground, water) due to the capacitive effect. It technically still happens when in the air, just to a much smaller extent. HVAC's benefits are that it is cheap to make transformers for. It is relatively easy to kick it up to 2MV then down to 240V. The often cited reason AC won over DC is that you can transmit it for cheaper, which isn't totally true, the reason AC won is because you can transform it easier. It was much easier to generate power at 40V, bump it up to 1kV, then down to 240V. Higher voltage == less line loss.
  - mc32 7y ago
    Do they convert AC to DC back to AC to connect western Japan to eastern Japan electric grid systems?
    - jacobush 7y ago
      Wikipedia said: "The electrical grid in Japan is isolated, with no international connections, and consists of two wide area synchronous grids which run at different frequencies and are connected by HVDC connections. This considerably limits the amount of electricity that can be transmitted between the north and south of the country."
  - toomuchtodo 7y ago
Gravityloss 7y ago
Very efficient. There are over 2000 km distances (1200 miles) in China. https://en.wikipedia.org/wiki/List_of_HVDC_projects https://en.wikipedia.org/wiki/List_of_HVDC_projects

adrianN 7y ago

This article here contains some helpful information: https://en.wikipedia.org/wiki/HVDC https://en.wikipedia.org/wiki/HVDC

std_throwaway 7y ago
"HVDC transmission losses are quoted as less than 3% per 1,000 km"
snaky 7y ago
> China is the global test bed for ultra-high voltage (UHV) transmission lines, a technology that can carry electricity across vast distances with much greater efficiency than the high voltage lines that you’re probably used to seeing. > Since 2006, it’s built 19 of these multi-billion-dollar lines, stretching almost 30,000 kilometres and supplying 4% of national electricity demand. For comparison, no other country has a single UHV line in full commercial operation. > But China’s enthusiasm for UHV is waning. The technology is beset by conflicts of interest between grid companies and central and local governments. The lines themselves are underperforming, and more recent projects are coming online amid a period of electricity generation overcapacity. > This means that approvals for new lines have slowed, and grid companies are unlikely to meet their targets for new ones. https://www.chinadialogue.net/article/show/single/en/10376-Sparks-fly-over-ultra-high-voltage-power-lines https://www.chinadialogue.net/article/show/single/en/10376-S...
deleted 7y ago
[deleted]
SECProto 7y ago
even more helpful info here: https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity_transmission_in_China https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity...

benj111 7y ago

There isn't really a hard limit, the longer the cable, the bigger the losses. You can mitigate that somewhat by increasing the voltage, which is what they're doing. So basically the distance is determined by economics. If China could install solar and cables cheaply enough, then they could compete with domestic European and American electricity. I find that doubtful though.

exabrial 7y ago

Hvdc can go a very very long way; thousands of miles economically. 500kv a.c. @ 60z starts to become impractical above 1000 miles if I recall correctly. I'll not sure how 50hz power is more or less affected on transmission, but it requires larger transformers, making each conversion step more expensive from a fixed cost perspective. Edit: I didn't recall correctly, looks like hvac is not very effective above 700mi, and in underground and underwater applications, far less.

cogman10 7y ago
HVDC has a few benefits. First, because you need to turn it into AC eventually and it doesn't have a frequency, it makes connecting grids a snap. You can hook a 50Hz grid to a 60Hz grid or even just two 60Hz grids with different phases. The lack of alternating means you can bury the line. HVAC will lose power when it is close to conductors (ground, water) due to the capacitive effect. It technically still happens when in the air, just to a much smaller extent. HVAC's benefits are that it is cheap to make transformers for. It is relatively easy to kick it up to 2MV then down to 240V. The often cited reason AC won over DC is that you can transmit it for cheaper, which isn't totally true, the reason AC won is because you can transform it easier. It was much easier to generate power at 40V, bump it up to 1kV, then down to 240V. Higher voltage == less line loss.
- mc32 7y ago
  Do they convert AC to DC back to AC to connect western Japan to eastern Japan electric grid systems?
  - jacobush 7y ago
    Wikipedia said: "The electrical grid in Japan is isolated, with no international connections, and consists of two wide area synchronous grids which run at different frequencies and are connected by HVDC connections. This considerably limits the amount of electricity that can be transmitted between the north and south of the country."
- toomuchtodo 7y ago

Gravityloss 7y ago

Very efficient. There are over 2000 km distances (1200 miles) in China. https://en.wikipedia.org/wiki/List_of_HVDC_projects https://en.wikipedia.org/wiki/List_of_HVDC_projects