Energy crisis – do not put the clocks back

Darkness and peak electricity demand

Sir, – DST (daylight saving time) was introduced in many countries during the first World War to reduce fuel use. The UK had DST throughout the year from 1940 to 1947 and the US had continuous DST from 1942 to 1945 for the same reason.

If DST were kept in Ireland over the winter, the total number of hours of darkness (after lighting-up time) between 5pm and 7pm would drop from 241 to 148.

In Ireland last year, the change from DST to winter time resulted in a large increase in the peak electricity demand. On the Tuesday to Friday before the change, the average peak was 4,450MW (megawatts).

On the corresponding days after the change, the figure was 4,920MW, an increase of 370MW (8 per cent).


This is more than the 260MW of planned emergency generation which will not be ready this winter and the 5 per cent reduction mandated by the EU.

If the clocks are not put back this winter, the electricity peak demand would be lower, resulting in lower prices paid to all generators and a reduction in the risk of blackouts.

The peak electricity demand in Ireland and the UK would then be offset by one hour, enabling more efficient use of the interconnectors for rescue flows.

Being on a different time zone from any particular country is unlikely to cause problems as Ireland now operates very much in a globalised world.

In addition to reducing peak demand, total energy use would also decrease due to the greater use of the available daylight, especially in February and March.

A large-scale study in the US in 1999 by Coate and Markowitz suggests that maintaining DST throughout the winter would significantly reduce the number of road accidents. They estimated that the total number of pedestrian fatalities would be reduced by 13 per cent and vehicle occupant fatalities by 3 per cent between the combined hours of 5am to 10am in the morning and 4pm to 9pm in the evening.

Due to the ongoing energy emergency, the clocks should not be put back on October 30th this year.

This would reduce the risk of power blackouts, in addition to reducing overall energy consumption over the coming winter. – Yours, etc,



Co Dublin.