daylight savings time impact dst impact goal - estimate the change in energy due to dst approach...
TRANSCRIPT
Daylight Savings TimeImpact
DST Impact
Goal - estimate the change in energy due to DST
Approach – Measure energy before and after the DST date
DST Impact Two days were used for comparison
• Selected one day before the DST change and one after• Attempted to make sure that the weather was as close
as possible• Chose the same day of the week• Used 560 residential sample accounts from GPC
Compared the five morning hours and five evening hours• Any potential DST impact would occur the during 5am
- 9am and 7pm - 11pm hours
DST Impact
Chose April 3 and April 17, 2003• Both days were Thursday• Similar hourly temperature
morning 3-Apr 17-Apr evening 3-Apr 17-Apr
5am 52 59 7pm 71 66
6 51 58 8 68 66
7 51 58 9 66 65
8 55 58 10 64 65
9 60 60 11 63 64
average 54 59 average 66 65
DST Impact
kW demand between the two days was not significantly different
kW 3-Apr 17-Apr
morning 10.1 9.9
evening 11.4 11.7
Paired t-test was used to statistically determine if the difference in usage was significant• t-test results showed no change in usage after the DST
shift
DST Impact
Repeated the analysis with two random days Chose April 1 and April 8, 2004
mean temp 1-Apr 8-Apr
morning 39 58
evening 48 67
April 1 was a much colder day than April 8
DST Impact Unlike the first test, there was a significant
difference in usage between the two days
mean kW 1-Apr 8-Apr
morning 10.1 7.4
evening 9.9 8.2
April 1, which was much colder, had a higher kW usage than April 8
This process was repeated with other days, yielding similar results
DST Impact
Conclusions• When temperatures are somewhat
similar, there is no significant difference in usage
• Temperature has an impact on demand
• DST does not affect demand
DST Impact
A separate analysis was done using Alabama residential data• ANOVA test (similar to paired t-test) was used
• Looked at each day for the entire week before and after DST
• Examined the two hours before/after sunrise Identical conclusions were reached
• Temperature is the key driver of demand
• DST does not influence demand