EirGrid: Supporting grid stability on a renewable-led electricity system
EirGrid balances electricity supply and demand in real time from its National Control Centre.
Operating a power system with electricity generated from high levels of variable renewables, such as wind and solar, is complex and technically very challenging.
There’s a need to overcome the limitations of many established technological and operational practices, while making sure the grid remains stable and secure.
EirGrid, which is responsible for operating, developing and enhancing Ireland’s electricity grid and market, can currently operate the system so that up to 75 per cent of Ireland’s electricity generation can come from variable renewables at any one time. This is high by international standards.
“A significant further evolution of the operation of the power system is required to achieve the unprecedented levels of renewables being targeted by Government over the next decade and beyond,” according to Eoin Kennedy, Director of Innovation and Planning at EirGrid.
EirGrid balances electricity supply to customer demand in real time from the National Control Centre. The complexity of this task is compounded greatly as more renewables are brought onto the system.
To maintain stability on the grid, EirGrid engineers need to be able to adjust to and meet fluctuating energy demand with supply at all times, and maintain resilience against other potential disruptions that can arise.
“We don’t have control over external conditions which allow for high levels of renewables onto the system, so we need to put new technology and practices in place,” according to Kennedy.
With that in mind, EirGrid has introduced new tools to the control centre, including a groundbreaking look-ahead security assessment tool.
This allows operators in the control centre to run simulations every five minutes to understand how the electricity system will react to situations that might arise, when there is greater reliance on renewables.
“We’re working with stakeholders to remove barriers to new technologies so that renewables can be brought on at scale, while ensuring that we have the right control centre tools and operational capabilities to manage the increased complexity of the grid,” says Kennedy.
When operating an electricity system, ensuring a sufficient level of inertia is critical for maintaining grid stability.
Traditionally, inertia could only be provided by large fossil-fuel burning conventional generators, through the presence of heavy rotating equipment.
To help move away from this reliance, last year, EirGrid awarded four contracts for renewable energy integration technologies, called synchronous condensers, which will provide ‘low carbon inertia services’ (LCIS) when delivered over the coming years.
This technology is vital for maintaining stability on the electricity grid while operating with higher levels of renewable energy.
In April 2024, EirGrid also reduced the minimum number of large conventional fossil-fuelled generators that must operate on Ireland’s electricity grid at any one time.
Again, a minimum number of large conventional fossil-fuelled generators are required to run to ensure the stability of the power system.
“Through a trial from May 2023 to March 2024, we were able to successfully demonstrate that this minimum requirement can be reduced from five to four large generators, when system conditions allow,” continued Kennedy.
During the ten-month trial, these conditions were met for approximately 11% of the time. At times of lower renewable generation availability, a larger number of fossil-fuelled generators will still be required to operate to meet power demand.
The LCIS technology will enable the minimum number of units to be further reduced over time.
EirGrid also has to manage disturbances on the power system, which can cause the frequency to change.
The technical term for the rate of this change is known as rate of change of frequency (RoCoF).
Higher levels of renewables replacing conventional fossil fuel generation leads to reduced system inertia and potentially increases this rate.
“Working with our partners and key stakeholders, we have been able to increase this RoCoF limit, to help bring more renewables onto the grid,” says Kennedy.
The power system will undergo a radical transformation between now and 2030, and beyond to 2035.
This will include greater interconnection, the connection of offshore wind, more onshore wind and solar generation, and storage.
Additionally, our economy and society are changing, with demand anticipated to increase.
“We have a roadmap in place which charts a pathway for the evolution of operational policy to facilitate these radical transformations while maintaining and enhancing security of supply, reliability and resiliency,” concludes Kennedy.
For more information, visit: EirGrid.ie
