Berry Islands, Bahamas | 4-MW PV + 10-MWh battery
Few sites on the planet represent the intersection between an island, ocean and energy resources required to operate a resort — in a safe and environmentally friendly way — more than our Solar + Storage Project of the Year, the Chub Cay Microgrid. The project required designing both the PV field and battery storage system to withstand the high salinity and hurricane-prone location 1,000 feet from the ocean.
“It is the biggest and most resilient microgrid of its kind in the Bahamas and likely the Caribbean,” says Justin Cunningham, general manager of Compass Power. “Wind rating, longevity, output and storage capacity, the Chub Cay project moves boundaries when it comes to what can be done with renewable energy-driven microgrids.”
Exorbitant electricity prices, poor reliability and the climate impact of diesel-power plague Caribbean islands. The self-sustaining microgrid is the perfect solution for the Chub Cay private resort, which wanted to reduce its carbon footprint and its reliance on diesel. Solar, which costs half that of conventional sources in the Caribbean, was paired with two 5-MWh lithium-ion batteries and four bi-directional 1,000 KVA PCS inverters. Over eight months, Bahamian EPC Compass Power executed the largest autonomous and independently operated microgrid in the Bahamas, using primarily Bahamian labor.
“The logistical undertaking of building a microgrid of this magnitude in such a remote location added significant complexity to the project,” Cunningham says. “It required a deeper and more detailed engineering program and a better understanding of the full BOM, equipment and tooling required to execute the work.”
Building materials and specialized equipment and manpower had to be chartered on dedicated vessels, requiring tight coordination between Compass Power, the port authorities and partners. Compass Power assembled a team of TerraSmart, Hitachi ABB Power Grids, Trina Solar, Yaskawa Solectria Solar, Resitech Industries, S&C along with Asante Energy for engineering and construction management.
Once two rounds of geotechnical surveys were conducted to determine soil composition and capacities, Terrasmart’s ground screw solution was the only viable option to penetrate the island’s solid oolite limestone. Driven piles in costly concrete foundations were not feasible, either structurally or financially.
Compass Power worked with Terrasmart (which just had its own big re-branding news here) to customize the system to tolerate hurricane-force winds up to 185 mph and gusts up to 210 mph with a low-tilt form factor and a specialized module frame ensured durability. TerraSmart engineered six mounting locations, instead of four, to secure the modules to the racking structures to achieve the required uplift ratings. The battery system structure is built to withstand the same forces. Additionally, Compass Power designed detailed lightning protection system, covering the entire array.
Paired with a 10-MWh battery energy storage system, the microgrid boasts a 90 percent reduction in fossil fuel usage at the resort.
And get this…
Despite being the largest solar array in the Bahamas, and one of the largest grid-forming systems, the Chub Cay renewable microgrid was built and commissioned without delays in eight months. While creating significant climate benefits, this landmark installation will generate 6,785 MWh of energy per year and save millions of dollars in fuel for the private resort and its marina.
“Complemented by a few industry experts, the knowledge and skills acquired by our team will hopefully transition to a broader understanding and acceptance of microgrid use in the Bahamas,” Cunningham says.