Wärtsilä energy storage systems keep island grid secure

Wärtsilä will supply two 10 MW/10 MWh energy storage systems under an Engineering, Procurement, and Construction (EPC) contract to Caribbean Utilities Company Ltd (CUC) in the Cayman Islands. The project, which will be CUC’s first energy storage facilities, will enable the utility to approximately double its renewable energy capacity on Grand Cayman, the largest of the three Cayman Islands.

Wärtsilä will supply two 10 MW/10 MWh energy storage systems consisting of its GridSolv Quantum integrated energy storage system and GEMS Digital Energy Platform software, to Caribbean Utilities Company Ltd (CUC) in the Cayman Islands. (Photo: Wärtsilä)

The new energy storage facilities are engineered to allow CUC to operate its generating assets in a more efficient manner, reducing fuel costs to electricity consumers. Additionally, the energy storage systems will facilitate up to a total of approximately 29 MW of distributed customer-sited renewable energy resources without causing instability to the grid.

The systems are also part of CUC’s commitment to reducing Scope 1 greenhouse gas emissions by 75% by 2035, using 2019 as a baseline. The company aims to achieve that target through various projects including the installation of utility scale solar and storage, natural gas procurement, purchase of electric vehicles and expanding the amount of EV charging stations on Grand Cayman.

“We are pleased to work with Wärtsilä to establish our first energy storage systems,” said Sacha Tibbetts, vice president, Customer Services & Technology, Caribbean Utilities Co. “This represents a crucial step for CUC to integrate more renewable energy into the grid. Once this project is completed, we anticipate savings on fuel costs and improved reliability of services for our customers on Grand Cayman,”

CUC is a privately owned electricity generation, transmission and distribution utility which owns an installed generating capacity of 161 MW of diesel-fueled generation and approximately 14 MW of solar photovoltaic (PV) generation. The PV system includes a 5 MW solar farm, the first commercial solar project in the Cayman Islands, that incorporates 21,690 poly-crystalline photovoltaic (solar) modules each with a dc-rated capacity of 305 W.

Unique challenges

CUC is the only electric utility in Grand Cayman, the largest island of the Cayman Islands, with a population of approximately 65,000 mostly residing in Grand Cayman.

A rendering of the location of the Wärtsilä energy storage facility behind the Hydesville Substation in West Bay, Grand Cayman. (Photo: CUC)

Island grids face unique reliability and resiliency challenges outside the normal in intermittency issues inherent to renewables. Like many island grids, Grand Cayman’s power system is isolated from grid-tied electricity, and susceptible to unplanned changes in power generation output.

“Energy storage has proven to be a game changer for our numerous island-based customers in the Caribbean and beyond to simultaneously lower energy costs, reduce greenhouse gas emissions, increase renewable energy consumption and improve grid reliability,” said Jon Rodriguez, director, engine power plants, Wärtsilä Energy in North America. “Our industry-leading solutions empower islanded grid operators to optimize and modernize their energy systems, and we are happy to assist CUC along this path.”

The Wärtsilä energy storage systems will be connected to the Hydesville, West Bay and Prospect substations. Each facility will include Wärtsilä’s GridSolv Quantum integrated energy storage system, as well as the GEMS Digital Energy Platform, Wärtsilä’s energy management system.

The systems are expected to provide extensive power system optimization capabilities, chief among them to offer “instantaneous or spinning reserve” in the event of power generation plant failure. By replacing the spinning reserve normally provided by CUC’s online generators, fewer generators will need to be online, significantly reducing the amount of fuel consumed for electricity production, with the cost savings passed on to customers, CUC said.

The battery will also have the ability to react much faster than the existing plant, reducing the risk of customer outages caused by loss of generation.

The GridSolv Quantum is a modular battery enclosure with pre-installed liquid-cooled battery racks and all sub-systems such as HVAC, ac and dc outdoor rated cabinet, which interfaces battery strings with the inverter and provides an interface for auxiliary power and communications interconnection busbars and cables.

The Wärtsilä GEMS software will help manage all of CUC’s generation assets, including a 5 MW solar farm. (Photo: CUC)

Island experience

The GEMS software platform integrates and controls individual resources and entire fleets comprising energy storage, renewables and traditional thermal generation. Using machine learning and historic and real-time data analytics to optimize the asset mix, the software enables users to remotely monitor, operate and identify and diagnose equipment, Wärtsilä said.

The systems are expected to become operational in late 2023.

Wärtsilä said it has more than 70 grid-scale system installations for its energy storage technology globally, integrated with wind, hydro, solar and thermal generation. It is also no stranger to optimizing island power grids, as its GEMS software and GridSolv energy storage systems are being used to manage 4.5 MW of wind energy, 1 MW of solar and 2.5 MW of energy storage on the island of Graciosa in the Azores, as well as provide 25 MW of energy storage for Bahama Power and Light.