2011-03-23 20:54:23Japan, hardly a model of power flexibility!
perseus

owlsmoor@googlemail...
78.143.223.193

I initially thought the power shortage in Japan was due to a large number of power stations being shut down for safety reasons, but it seems that only a handful of plants have actually been affected. Surely with a few conservation measures here and there they should be able to manage? The problem is exacerbated by East and West Japan not being able to transfer electricity to one another due to using different frequencies!

Quote:
The 50 hertz frequency in eastern Japan and the 60 hertz of the west, adopted during the Meiji era more than a century ago and formally instituted at the end of World War Two, would be hugely expensive to unify, given different standards for electric motors and appliances.

"The capacity for linkage between the west and the east is only 1,000 MW. It will take at least two to three years to double or triple that capacity even if there is a will to do so," Manabe said.

Having two seperate grid systems, especially for a country which needs a more flexible response to disasters is archaic to say the least. Neither does this give much hope for them being able to cope with intermittent renewable energy, or demand management strategies.  This left wing site seems to think the source of the problem is political

The International Energy Agency (IEA) has pointed out that the Japanese thermal power plants are only responsible for 30% of their capacity and it is actually possible to supply sufficient power with the other thermal power plants even if all of the nuclear power plants were stopped.

The UK and France have an interconnector (2GW) which is twice the capacity that of Japan has between its own networks! 

2011-03-24 02:30:29
Paul D

chillcast@googlemail...
82.18.130.183

Is that really true??

Different frequencies?

Years and years ago (1980s) I worked on a power supply for a small lable printer for the Japanese market and I don't remember that being an issue.

I assume they have connecting cables between islands??

Maybe the frequency is homogenised at the domestic level??

2011-03-24 02:32:46
Paul D

chillcast@googlemail...
82.18.130.183

2GW interconnector isn't much either. About 3 power stations worth.

2011-03-24 02:40:14
Paul D

chillcast@googlemail...
82.18.130.183

Your correct perseus. Although this map shows two links between the two:

http://en.wikipedia.org/wiki/File:Power_Grid_of_Japan.PNG

It isn't impossible to change frequencies in order transfer energy, although there are probably losses.
These days, power is converted form DC, to AC and back quite a lot using converters and inverters, but it can produce harmonics in the current.

"In Japan, the western part of the country (Kyoto and west) uses 60 Hz and the eastern part (Tokyo and east) uses 50 Hz. This originates in the first purchases of generators from AEG in 1895, installed for Tokyo, and General Electric in 1896, installed in Osaka. The boundary between the two regions contains four back-to-back HVDC substations which convert the frequency; these are Shin Shinano, Sakuma Dam, Minami-Fukumitsu, and the Higashi-Shimizu Frequency Converter."

http://en.wikipedia.org/wiki/Utility_frequency

Looks like they use converters and inverters to go from 50hz to DC then to 60hz and vice versa.

2011-03-24 05:24:54
perseus

owlsmoor@googlemail...
78.143.199.128

S Korea which is installing a smart grid has 60Hz, unfortunately it is 220v rather than 100v as in Japan, so it would be complicated building an interconnector to Japan from there. I think the problem area in Japan is the 50Hz portion anyway. 

 

2011-03-24 23:29:38
MarkR
Mark Richardson
m.t.richardson2@gmail...
83.150.146.79

Isn't voltage really, really easy to change with very little loss? We have very efficient transformers.

 

Frequency is the problem!