[tz] Japanese Summer time fallback transition in autumn 2020?

Paul Eggert eggert at cs.ucla.edu
Tue Oct 2 09:29:26 UTC 2018

Phake Nick wrote:
> there's a report from Japanese government back in year 1999 that
> said the total reduction of energy consumption due to summer time would be
> about 5 million liter petroleum

Unfortunately I have no easy access to that 1999 report by the Japanese National 
Council to Think About Global Environment and Daylight-Saving Time, which is 
archived in the US Library of Congress 
However, independent scientific research tends to be more reliable than 
government-sponsored reports for this sort of thing. And as far as I can tell, 
recent research has not demonstrated significant energy saving for DST in Japan. 
Admittedly I am hampered by the language barrier as I don’t read Japanese; that 
being said, I looked for publications in Japanese or English and found only two, 
cited below: one suggests DST would waste electricity and the other suggests DST 
would save electricity, and both studies are of course merely simulations, not 
empirical results.

For what it’s worth, the Havranek meta-analysis attempted to assess research 
study quality, and reported “The difference in implied DST savings between a 
study from a journal with a zero impact factor and an impact factor of one is 
0.96; better journals publish more pessimistic estimates of DST savings.” The 
two studies I mentioned are consistent with this finding.

>> Havranek T, Herman D, Irsova Z. Does Daylight Saving Save Electricity? A
>> Meta-Analysis. Energy J. 2018;39(2).
>> https://doi.org/10.5547/01956574.39.2.thav
>> with preprint at https://meta-analysis.cz/dst/dst.pdfyo

That last URL should be:

The two studies I mentioned above are:

Fong W, Matsumoto H, Lun Y, Kimura R. Energy savings potential of the summer 
time concept in different regions of Japan from the perspective of household 
lighting. J Asian Arch Build Engr. 2007;6:371-8. https://doi.org/10.3130/jaabe.6.371

Shimoda Y, Asahi T, Taniguchi A, Mizuno M. Evaluation of city-scale impact of 
residential energy conservation measures using the detailed end-use simulation 
model. Energy. 2007;32(9):1617-33. https://doi.org/10.1016/j.energy.2007.01.007

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