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Few savings to be made from not putting clocks back

about 17 hours ago

John FitzGerald

A gallery assistant adjusts the minute hand of the Royal Observatory clock in Greenwich. In 1968, Daylight Saving Time was adopted on an experimental basis in Britain and Ireland. Photograph: Johnny Green/PA




The sun dial was one of the earliest pieces of solar-powered technology, dating back about 3,500 years. While reliable timekeeping has been available using clocks since the 18th century, the position of the sun in the sky still determines our approach to time. The point at which the sun is at its zenith over Greenwich in London is defined as midday in the UK and other countries using Greenwich Mean Time (GMT).

Since 1884, the international standard for time zones is based on the meridian through Greenwich. Previously individual countries and regions operated their time systems from individual reference points ranging from Ujjain to Mecca, Cádiz to Washington. The French held on to Paris time until 1911, and Ireland also went its own way until 1916.

Until the needs of railway timetabling took over, time differed around Ireland, depending on when the sun was at its peak locally. To make the trains run on time, in 1880 Irish standard time was adopted. However, because the sun was at its zenith later in Dublin than in Greenwich, Irish time was standardised at 25 minutes and 21 seconds after British time.

This remained the situation till the Rising in 1916 triggered a decision to move Ireland to GMT, and after independence in 1922, we did not revert.

Summer time

The practice of shifting time by an hour in the summer was first adopted in Germany during the first World War to save electricity. In the UK, the Summer Time Act of 1925 brought in summer time and independent Ireland followed suit.

However, in 1968, Daylight Saving Time was adopted all the year round on an experimental basis in Britain and Ireland. This had the advantage that in the winter the time in Ireland was the same as in Germany and France. It also meant that it was bright later in the evening, potentially moving peak demand for electricity in the winter.

Britain decided to drop this experiment in 1969, partly because people were travelling to work and school in the dark in winter. However, there was some debate In Ireland as to whether we should again follow the British example or re-establish Irish time.

In his first General Election in 1969, Garret FitzGerald argued at a public meeting in Sandymount Green that Ireland should show its independence by continuing with the time experiment.

Brandishing Bradshaw’s 1914 Railway Timetable, he quoted from the timetable about the need to adjust your watch to Irish time when taking the mail-boat to Dún Laoghaire. He argued that if Ireland could be different from Britain in 1914, independent Ireland could also have its own time.

Irish time

Whether the Sandymount voters found this argument a convincing one is unknown, but he was elected. However, in his subsequent political career, the re-establishment of Irish time did not feature.

More recently, in 2012, Labour TD Tommy Broughan introduced the “Brighter Evenings Bill”, once again proposing to move Ireland to continental time. With interconnection of the British and Irish electricity systems, he argued that, by changing time, Irish peak demand for electricity could be moved so that it occurred at a different time from Britain.

Because catering for peak demand, generally between five and seven on a winter evening, is much more expensive than covering demand at other times of the day, spreading the peak could make significant savings in cost and in greenhouse gas emissions. This is because plant used to cover peak electricity demand tends to be much more inefficient than plant used to meet demand at other times.

This proposal to shift time to save on the cost of electricity built on the experience elsewhere, in places such as Australia and the United States.

A study I did with ESRI colleagues in 2014 looked at how such an experiment in changing time might actually work in Ireland. The peak in demand for electricity in Ireland in the winter is slightly after the peak in Britain, but the difference is very small. The peak often occurs within the same half hour in the day on the two islands.

As a result, switching to continental time in Ireland, while moving the peak demand to slightly before the British peak, would not result in significant savings. It is only if Ireland switched to the same winter time zone as Greenland that there might be significant savings to be reaped – a chilly thought. While brighter evenings in the winter might cheer us all up – except maybe “early risers” – there would be few financial savings.