Behind the scenes at the wind farm that is helping NI meet its renewable energy target
The first thing that struck me when visiting the wind farm at Carn Hill which overlooks Carrickfergus was the site’s unexpected tranquillity.
The generation of electricity is something that does not come easily and therefore something you may expect to bring its fair share of whirring and clanging.
Granted, my visit took place on a glorious summer’s day with only a little wind to put the turbines through their motions, yet as the 82-metre blades of the six wind turbines rotated around me, the only noise I could hear was the bleating of sheep who grazed in the shadow of the mighty machines.
Site manager Garret Walsh, said: “It’s a wind farm on a working farm. We try to be as low impact as possible.
“We rent the land from the land owners. They continue to farm it. It’s a very positive relationship. At the end of the day it’s a commercial relationship, but it does help an awful lot if you’re friends with your neighbours.”
The site is unmanned though it is Garret’s responsibility – as a CGN Europe Energy employee – to ensure the turbines are always at the ready to take advantage of optimum wind conditions: “Our job is to make sure the place runs safely and efficiently. We do a quarterly inspection, realistically we’re here more often than that.”
In its simplest form, the electricity generated by the wind which turns the blades of the turbines is transferred via 33,000 volt underground cables to CGN’s substation before being transferred to the adjoining NIE substation and then onto the grid at Carnmoney.
Standing nearly 100 metres tall from base to the tip of blade, the Enercon-manufactured turbines are made of steel and fibreglass and held in place by reinforced concrete foundations.
Each turbine at Carn Hill produces 2.3 megawatts (MW) of energy, a total of 13.8 MW for the site. Although electricity needs are dependent on season, that is roughly enough energy to power 8,000 homes for a year.
Garret explained the wind conditions needed to generate electricity: “The faster the wind is blowing the more electricity is generated.
“They start to generate electricity at around eight or nine miles per hour.
“When the wind gets up past approximately 55 miles per hour it has a safety cut off. You could be driving past a wind farm and it could be blowing a gale but the turbines aren’t turning.
“If it’s not turning it’s normally down to no wind or very high wind.
“It’s like anything, you drive it too fast and it starts to fail.”
Discussing the location of the wind farm and issues people have with the presence of large turbines on the landscape, Meabh Cormacain, manager of Northern Ireland Renewables Industry Group (NIRIG) said: “On shore wind farms need to be up high to make the most of the wind, Carn Hill in particular is one of the most visible wind farms in the UK given its location close to Belfast and sightline from North Down.”
“There’s a lot of misinformation about wind farms that can be counteracted with the right information. There’s only one thing I can’t argue with. If people don’t like how they look, that’s fair enough. It’s quite subjective.
“The turbines are designed to have a low visual impact, the paint is a sky-coloured shade of white, though not always the colour of skies you get here in Northern Ireland.
“There are a fair amount of people who say the turbines are quite relaxing.
“People are concerned with change. They can be uncertain about what a wind farm can mean for them. What we tend to see is that once the wind farm is operating people stop seeing it after a while. It’s like electricity pylons. You can’t imagine the landscape without them but you stop seeing them because you get used to them.”
While Garret is responsible for managing the turbines at Carn Hill, the maintenance of the machines is carried out by another company.
He said: “It may be a case you have to have a crane on site for a major component change. A lot of the work is done remotely, for example software updates.
“Our job as asset manager is to monitor performance. These windfarms are an asset, we need to run them as efficiently as we can. They can be monitored from Dublin, from Paris.”
Meabh said: “There’s times we’re not going to need all the energy that is being produced, for example, a fabulously windy day in the middle of the summer.
“The system operator has an extremely sophisticated set of management tools and they will be monitoring the output from every wind farm, every solar farm in as granular detail as they can get. They will be sending out signals to manage the output.
“Unfortunately when we have surplus energy that we don’t need we can’t export it because of our isolated island location, everything just gets turned down. We need better interconnection to help resolve that.”
Garret said: “Carn Hill would be one of the smaller wind farms. A big wind farm would have around 16 turbines and produce something like 40 MW, then you’ve got huge ones like Whitelee Wind Farm in Scotland which produces over 500 MW.”
Meabh said: “When you go off shore the energy capability leaps up even more. There are less restrictions. There are plans underway to developy a 12MW turbine. That’s basically the same as Carn Hill in one single machine off shore. One spin of a blade is sufficient to power a house for a day.
“That’s why the UK is moving so fast towards its renewable targets, by harnessing technologies, particularly off shore.”
For the 12 month period up until March 2019, 38.6% of NI electricity consumption came from renewable sources located in the Province – an increase of 2.1%.
Meabh said: “It’s a phenomenal achievement.
“With a bit of luck we’ll hit our 40% target well before 2020. We’ve also done it far more cheaply than anyone predicted.
“We have ambition to get to 70% renewables by 2030.”
She said: “In Northern Ireland 83% of renewable energy comes from wind, the rest is solar, biogas, tidal, hydro - probably in that order.
“Some days you’re generating very little from renewables, other days you need to be generating well above 40% to hit your average.
“SONI (System Operator for Northern Ireland) are managing this very variable electricity system.
“20 years ago they had to manage three power stations. Now they have to manage 20,000+ power stations because every house with a solar panel is a power station capable of selling energy onto the grid. Every wind turbine is a power station. They are world leading given the isolated system they’re managing. It would be great to see more recognition for that.”