Located near the River Shannon in rural County Kerry, the project, called Tullahennel, consists of 13 wind turbines with a total generation capacity of 37 megawatts. Each turbine comes with a lithium-ion battery, roughly the size of a small car, that’s located at the base of the tower. The batteries can store 69 kilowatt-hours of electricity apiece, feeding it into the grid as needed.
This hybrid approach reduces the need to fire up fossil-fuel power plants to pick up the slack when the wind stops blowing. It also allows the system to store excess electrons when demand is low, like on a windy Sunday. “One big problem with renewables is variability and availability,” says Amelie Wulff, hybrid solutions global sales leader at GE Renewable Energy. “With a battery you have a place where the energy can go until the grid is capable and has capacity to absorb that energy.”
For Ireland, the project is crucial: The country’s electrical demand is projected to increase between 15 to 36 percent over the coming decade, driven by the growth of data centers, according to EirGrid’s All-Island Generation Capacity report. Data centers already consume 6 percent of Ireland’s electricity, and under a 15-year purchase agreement, all of Tullahennel’s power generation will go to Microsoft Corp. data centers.
That burgeoning demand — coupled with the Irish government’s mandate to generate 40 percent of its electricity from renewable sources by 2020 — means there is a significant need for the country to embrace renewables as an essential part of its energy mix. Even as Ireland ranks high among European Union countries in the use of clean energy, it still gets 9 percent of its energy from the burning of peat, a sweet-smelling but environmentally filthy proto-coal dug from the island’s vast bogs.
Tullahennel’s impact is expected to reach far beyond Ireland too. The ability to effectively and affordably generate, store and distribute energy will provide a model for projects around the world. “There’s a lot of data that shows the cost of battery storage will continue to drop, and that will improve the case for integrated storage,” says Juanita Ojeda, hybrids marketing leader at GE Renewable Energy. “And regulation is now starting to be in the right place to make projects viable.”
The magnitude of the step forward represented by Tullahennel is belied by the simplicity of the concept of storing energy — after all, everyone uses batteries of some sort. Most batteries, however, can’t store and discharge energy repeatedly on an industrial level.
Researchers in GE labs in Niskayuna, New York, and Bangalore, India, have been working on a practical grid-scale storage system since 2011, according to Steve Bravo, wind and hybrids product manager at GE Renewable Energy. In 2014, GE tested batteries connected to wind turbines in California, and in 2015 deployed another system at a three-turbine commercial project in Texas. The team eventually built its storage system around the emerging standard of lithium-ion cells.
Beyond technical hurdles, the cost of storage has been another obstacle. Until now, it’s been more cost-effective to keep fossil-fuel power plants idling in the background to make sure there would always be the right amount of power flowing through the grid to meet demand. But dropping prices of lithium-ion batteries have started changing the storage math.
The Tullahennel project also benefited from the active encouragement of EirGrid, the transmission systems operator for the island. The authority included storage as part of its official program to expand renewable energy sources, becoming one of the first markets to create a commercial incentive for using storage.
Tullahennel’s turbines recently went online, and the battery systems are in the final stages of testing their on-demand injection of power into the grid. Early tests have been successful, showing that the system was quickly adjusting to grid demand and turbine power generation, according to an internal project update report from GE Renewable Energy.
“The storage industry is still figuring out what the most viable solution may be,” GE’s Bravo says. “From a technical standpoint, this is a proof point of how to use and integrate storage directly into a turbine and see how it will perform.”