Strengthening the stability and resilience of the Irish grid

Katie Wall, Lead Engineer, ESB Engineering & Major Projects, outlines the role that ESB’s new Synchronous Compensator will play in delivering a Net Zero future.

My name is Katie Wall and I am the Lead Engineer for ESB on the Moneypoint Synchronous Compensator project. Having a keen interest in STEM subjects in secondary school, I made the decision to leap from Listowel, Co Kerry to Dublin. After completing my undergraduate and masters degrees in electrical energy engineering at UCD, I joined ESB as an electrical engineer on the graduate programme in 2016.

So far I have worked on a range of technologies within new and existing ESB generation fleet here in Ireland and also abroad. In late 2020, I joined the Moneypoint Synchronous Compensator project.

ESB’s historic Moneypoint generating station in Co Clare has played a critical role in the country’s energy supply for almost 40 years. Today, it is at the centre of our ambitious drive to achieve net zero by 2040. ESB saw a clear opportunity to transition Moneypoint from being a cornerstone of the electricity system as a fossil fuel plant to being a cornerstone of a renewables future for Ireland.

The project, Green Atlantic @ Moneypoint, will see the site transformed into a renewable energy hub, helping Ireland to become a leader in green energy production. The multi-billion-euro investment will see a range of the latest renewable technologies deployed over the next decade. This will include floating offshore wind and green hydrogen production and storage, which will have the capacity to power 1.6 million homes, once complete, continuing ESB’s significant investment in the Mid-West region.

We were delighted to welcome Minister Eamon Ryan TD here in November for the official launch of phase one of the project – our new €50 million synchronous compensator. This major piece of technology was delivered alongside our partners Siemens Energy Ltd. This is the first synchronous compensator in Ireland and its flywheel will be the largest of its kind anywhere in the world.

So much work went into the project from the team – from the transportation via barge of the heavy equipment to our local jetty, completing construction within a busy operating power station, to bringing the unit from installation into testing and operation.

I am regularly asked what exactly a synchronous compensator, or condenser, is and what does it do. Historically, Ireland’s electricity grid consisted mostly of conventional generation. Think of it like a heavy steam roller travelling on a motorway, hard to stop or knock off balance. As we move forward and replace conventional fleet with more renewables, our grid becomes more like a bicycle trying to travel along a tightrope – easier to stop or knock off balance. So, we now need a safety net to allow us to produce electricity from renewables but still ensure the grid remains stable at all times. That’s where the synchronous compensator comes in. It is a safety net for the grid at times of high renewable generation.

A synchronous compensator removes the fuel, the combustion process and turbine from the equation that you would see in a conventional power station. Instead, you take a small amount of electricity in from the grid to start up, synchronise and allow the synchronous compensator to remain connected to the grid.

There is no electricity output from a synchronous compensator. When it is synchronised to the system, it provides two key stability services to the grid – inertia and reactive power.

The synchronous compensator and flywheel in Moneypoint provides 4000 MW of inertia to the grid which is the equivalent inertia contribution of two of the existing thermal units in Moneypoint. Onshore and offshore wind, and solar, play an important role in producing clean electricity but they do not provide this inertia and their output can be affected by sudden frequency events unless inertia is provided elsewhere on the system. 

Due to the intermittency of renewables, grid stabilisation technologies have an increasingly important role in a successful energy transition. With the rising share of renewable power and the shutdown of conventional plants, this is only the beginning for synchronous compensators as part of grid operations in Ireland.

Most significantly, the Moneypoint synchronous compensator with flywheel is a cost-effective and zero-carbon solution that will further strengthen the stability and resilience of the Irish grid and support ever-more renewables coming on stream, all in line with ESB’s Driven to Make a Difference: Net Zero by 2040 strategy.

Learn more about ESB’s Green Atlantic @ Moneypoint project at www.esb.ie