Tuesday, 4th June, was a very windy day. Average wind speed across the country was estimated to be 34 km/h, making it the windiest 4th June of the last six years, so it should have been a big day for Donegal wind farms. Justin Moran explains why it wasn’t.
Donegal has the third most installed wind energy of any county in Ireland. But just because it can produce enormous amounts of clean, affordable, electricity doesn’t mean it’s always able to.
Check out this map of the electricity grid in Donegal. Two things should jump out.
First, all the lines are black. This is because they’re 110 kV power lines, which means they’re not able to carry huge amounts of power. Put another way, if these were roads, it’s the equivalent of saying all the roads in, out and around Donegal are local roads with no national road network at all.
The second thing to notice is Cathaleen’s Fall. All of the power lines, and therefore all of the power, going into and out of Donegal travels through the substation there at Ballyshannon. It’s one of the most parts of the electricity grid for anyone living or working in Donegal.
So on a windy day like 4th June wind farms in Donegal should have been sending huge volumes of electricity through the Cathaleen’s Fall substation to the rest of the country as well as providing most of the county’s own demand.
The Power Line Outages Hindering Donegal’s Wind Energy
But there was a problem.
On 4th June The 110 kV power line from Cathaleen’s Fall to Binbane was out of action, making it extremely difficult for wind farms in Donegal to get their power out.
We estimate that approximately two-third of Donegal’s wind generation was lost over the 24 hours of 4th June, an estimated 3.8 gigawatt-hours of electricity, or enough, on that single day, to meet the annual power needs of more than 900 homes.
It also meant, since we couldn’t get this power out of Donegal to the rest of the country, that fossil fuel generation would have been brought online, producing more of the carbon emissions that are fuelling the climate emergency. Economically, it likely cost Donegal’s wind farms around €360,000 in 24 hours.
And the problem got worse almost immediately as the very next day the 110 kV line from Cathaleen’s Fall to Srananagh in Co Sligo was also taken offline.
Progress in Strengthening Donegal’s Power Grid
Now, there is some good news.
The reason the Binbane – Cathaleen’s Fall line was out of action was to upgrade it and it recently reconnected to the system after being down for six months. The Srananagh connection was only down for a few weeks, again to improve the line, and was back in action by the middle of August.
So EirGrid and ESBN are hard at work strengthening the county’s electricity grid but we shouldn’t be seeing huge volumes of lost electricity because lines need to be taken down for routine upgrades and maintenance. The grid should be strong enough to get the power to where it’s needed even with a line out.
This is why EirGrid’s plan for a new 220 kV power line – which can carry a lot more electricity than the existing 110 kV network – which would link Srananagh, in Co Sligo, with and Clogher in central Donegal so important. This would greatly reduce the amount of clean power we’re losing nearly every day in Donegal.
That’s why it’s so important to #BuildOurGrid and to ensure one of the country’s windiest counties can play its full potential in delivering Ireland’s cheapest renewable electricity to homes, communities and businesses around Ireland.