How ‘Dimming and Trimming’ LED lightbulbs will save Mayo over €800,000 a year
of County Mayo's public lights have now been converted to LED, Mayo County Council has confirmed, with the authority on course to meet its Climate Action Plan target of full conversion by 2029, and possibly sooner.
Senior Engineer Peter McLoughlin told councillors that Mayo manages around 18,000 public lights, roughly 80% of which are council-owned and 20% on ESB networks.
"In terms of climate action, our climate action plan requires us to convert all the public lighting in County Mayo to low energy LED by 2029," he said. "So we're currently on target to achieve that. So I suspect we'll be substantially complete in advance of that deadline."
Total expenditure on the remaining lighting projects is estimated at €5.7 million, of which €3.5 million has been spent to date. Funding comes from the local authority, the Climate Action Fund, and TII in relation to network assets.
Mr McLoughlin outlined the results for 2025, during which around 3,400 lights were converted. The work saved 937 kilowatts, equating to about 509 tonnes of CO2, and delivered an energy saving of €220,000, equivalent to taking over 200 cars off the road.
Once the programme is complete, the council estimates savings of €821,000 per year, with a projected reduction of 3,500 megawatts per hour. LED lights have a lifespan of up to 20 years, and the transition can reduce energy costs by approximately 55%.
However, rising energy prices have eroded some of the gains. "There has been serious inflation on energy and diesel costs, so a lot of the savings have been negated by the increases in energy costs," Mr McLoughlin said.
Mr McLoughlin explained that LED lights are more concentrated and directed, and that the council has been "dimming and trimming". The latter, he said, refers to the old sodium lights, which had to be switched on 20 minutes to half an hour before they were needed because they took time to warm up. LEDs, by contrast, reach full strength as soon as they are switched on.
The council is also working with the Dark Skies initiative in Newport , using lower colour lighting to meet dark sky requirements. More aggressive dimming profiles remain a challenge at present, Mr McLoughlin said, though he expects them to "come to the fore in the next few years."
The biggest challenge identified was non-compliant cabling associated with a percentage of the county's public lights. Mr McLoughlin said this wiring will have to be replaced at significant cost. "It's not a cost that the local authority can bear on its own," he said, adding that the issue will be looked at nationally, with a report on asset replacement currently being prepared.
He also noted that changes to lights are prohibited on certain networks where the network is not separated or appropriate meter cabinets are not in place, which can delay upgrades.
Unfinished Housing estates
Cllr Annie May Reape highlighted unfinished housing estates where residents live without adequate street lighting, due to builder liquidation or handover delays.
Cllr Richard Finn said a new link road built around the playing pitches in Claremorris had been fitted with ducting and wiring for public lighting, but no lighting has yet appeared. He argued that lighting in occupied unfinished estates should be treated as an emergency. "It's a prerequisite that lighting should be a serious issue in relation to people's health and safety in unfinished estates," he said. Cllr Finn also questioned the concept of light pollution, saying he could not understand why it was such a major issue, and that "the more light we have, the better."
Cllr Damien Ryan asked about the retrofit of Cong , which had been scheduled for 2024. He said he had provided funding to connect the school by way of public lighting, and that this had been held up pending the other scheme. Mr McLoughlin said he was unsure of the specifics but would look into it, and agreed to return to Cllr Ryan with an update.
Responding to unfinished estates, Mr McLoughlin said the matter had been referred to the Municipal Districts at the last roads meeting. "What we're trying to do is get the worst cases first," he said. He added that there is "always new demand for lighting", including for active travel routes and housing estates.
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