Sustainable Cooling: A Deep Dive into Seawater Air-Conditioning (SWAC) Solutions for the Caribbean

As global temperatures continue to rise and the demand for cooling surges, the need for sustainable solutions become increasingly urgent. Absent improvements in technology and practices, energy for cooling needs will triple by 2050, straining local power grids and generating substantial harmful emissions.

The Caribbean Sea presents an opportunity to leverage its natural cooling properties through seawater air-conditioning (SWAC) technology.  By tapping inexhaustible cold, deep seawater, SWAC replaces traditional mechanical chillers and in the process, reduces energy consumption by up to 90%. 

SWAC systems are very simple. A pipeline fully resistant to seawater corrosion is installed from the shore to a depth of about 900 meters. Cold seawater from that depth is pumped to the surface where it cools coastal facilities before being returned to the ocean. Experiences in the South Pacific and other regions demonstrate that marine life and coral reefs can thrive in areas where the ocean water is reintroduced.

SWAC has demonstrated high reliability in many facilities around the world – including for the largest hospital complex in Tahiti – and in most cases, leads to a reduction in costs compared to conventional systems. 

SWAC is particularly promising to the Caribbean for several reasons: high electricity prices, heavy reliance on imported fossil fuels, favorable bathymetry and large and growing cooling needs along the shoreline. Roughly 20% of the region’s GDP comes from tourism and air conditioning represents a staggering 55% of total electricity consumption in hotels. Given the high cost of electricity in the Caribbean, this places a considerable strain on the hospitality and tourism sectors’ competitiveness so a solution like SWAC is very compelling.

Results in the Caribbean

With support from PROBLUE, the World Bank's Blue Economy Program and Energy Sector Management Assistance Program (ESMAP), the World Bank engaged SWAC experts, AIRARO, to analyze  the challenges and benefits of SWAC in the Caribbean and  identified the most promising islands for SWAC implementation., The team then did  in-depth technical and economic design studies for the most promising sites, which included marine pipeline engineering, anchoring systems capable of withstanding Category 5 hurricanes, fully buried technical rooms to house pumps, heat exchangers, and an optimized distribution network. These studies can provide valuable insights for potential investors interested in scaling up this technology in the Caribbean and other Small Island Developing States (SIDS). The studies identified the Dominican Republic, Jamaica, and Grenada as the most attractive for SWAC.

• In the Dominican Republic, a SWAC system was designed for the Pedernales tourism development project in Cabo Rojo, which aims to transform the southern coastal region of the Dominican Republic into a major tourism center, starting with 4,700 hotel rooms. As a sizable greenfield project with significant cooling needs and a strong desire for sustainability, SWAC is a compelling option. The first phase of the Pedernales project will require 7,100 tons of cooling power, which a US$70 million SWAC system could provide, reducing electricity usage by 94.5%, avoiding 63,000 barrels of fuel annually, and saving 30% on overall costs compared to conventional options.

• In Jamaica, the study identified the new Sandals Resorts International Runaway Bay Project, which would require 854 tons of cooling. A SWAC system in this location could reduce electricity usage by 92%, avoid the use of 7,300 barrels of fuel, and save 25.4% on air conditioning costs annually. The total capital expenditure for the SWAC system is estimated at US$16.5 million.

• While in Grenada, the SWAC project on the southwestern coast was designed to meet the cooling needs of the Maurice Bishop International Airport, St. George's University and two nearby major resorts. The feasibility study estimated that a district SWAC model could provide 3,500 tons of cooling with a US$50 million investment. The SWAC system would reduce electricity usage by 83%, avoid 21,000 barrels of fuel annually and achieve more than 40% annual savings compared to conventional cooling options.

Next Steps

The World Bank is supporting Government counterparts with technical assistant to better scope existing opportunities in this area. The next phase includes designing the best business/governance arrangements for the facilities; refining the design and costing for each facility; and ensuring environmental integrity and identifying financing schemes.

These SWAC facilities could provide an innovative solution to address the region's energy needs while advancing sustainable development and climate resilience. These initiatives would not only deliver significant economic and environmental benefits but also attract new investment for the region and make the Caribbean a leader in sustainable tourism and renewable energy technology.