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Can Caribbean islands modernize their way to affordable, resilient energy grids?

November 08, 2017

By Mike Voll

Storms like Irma and Maria expose the cost and vulnerability of diesel-based energy; renewables and battery storage will change the game

“Energy storage can be used today to help strengthen Caribbean electricity grids as well as the Caribbean economy!” This was the message echoed by participants of the Caribbean Renewable Energy Forum held in Miami in October. The two main themes that emerged at the CREF 2017, from both the presentations and discussions, were the cost of electricity and the need for resilient energy grids. To the first point, Caribbean islands pay more for electricity than most other places in the world. To the second point, the electricity grids of Caribbean islands are impacted more from weather events than many other places in the world. Our presentation on grid modernization and energy storage explored technologies that can help address both key themes for Caribbean energy grids.

Energy Costs for the Caribbean

Island grids are highly dependant on expensive and emitting diesel fuels that power most of their generators. Renewable energy from solar and wind are one way for the islands to become less dependant on diesel fuel. The problem is that renewable energy (RE) from solar and wind is intermittent and not entirely predictable. RE only produces power when the sun shines and the wind blows.

If islands try to integrate more than 30% of their supply mix from renewables, it can cause instability and inefficiency with the existing grid and diesel generator fleets. For example, if solar is providing the primary power for a critical facility and a cloud passes over the panels, the solar energy output from the array will be reduced. If the dip is significant, then the grid operator will have to dispatch a diesel generator to make up the difference. The frequent starting and stopping of diesel generators to accommodate this fickle solar energy is what causes inefficiency in the system.

A cyclist rides through the devastation caused by Hurricane Maria in Humacao, Puerto Rico. (U.S. Air Force photo by Tech. Sgt. Larry E. Reid Jr. The appearance of U.S. Department of Defense [DoD] visual information does not imply or constitute DoD endorsement.)

This is where energy storage can play a part. By coupling an energy storage system (like batteries) with solar or wind farms, the combination can behave as predictably and efficiently as a traditional generator—and, in some cases, even better since batteries can respond quicker than diesel generators. For example, by storing excess solar energy produced during mid-day in the batteries, the utility can use this stored energy during a peak electricity demand period avoiding having to start another diesel generator. This is known as “spinning reserve” and is one of the primary applications for energy storage on the islands.

Many Caribbean islands are in the process of either installing or procuring significant amounts of renewable energy. By coupling these procurements with an appropriate amount of energy storage, these communities will realize the dual benefit of clean, self-generated energy along with a stable spinning reserve.

By coupling an energy storage system (like batteries) with solar or wind farms, the combination can behave as predictably and efficiently as a traditional generator.

Resilient Energy Grids for the Caribbean

The second major theme that emerged at CREF 2017 was the need for resilient energy infrastructure that can adapt and respond well to grid disruption events following severe storms and hurricanes.

Traditional island grids are “central” in nature, since there’s typically a single generator fleet located on one portion of the island and a power delivery via overhead or underground wires to other parts of the island. As a result, if something impacts the central plant (or any of the connecting lines) then power is lost to the entire island. Relief efforts are slow due to limited resources, which can leave these communities without power for weeks or even months.

By utilizing the same storage-renewable combination mentioned earlier for certain critical communities or infrastructure (like a hospital, an emergency relief center, or a small town), this system can essentially behave like a “microgrid” and provide some power to that community from solar and batteries independent from the central grid. This function of disconnecting from the central grid and running independently is known as “islanding.” To coin a new phrase, “islanding on the islands” is of huge interest to these communities. This allows the utility time to focus their immediate efforts on other critical connections while the microgrid community keeps the lights on.

Next Steps

How to get these projects started? Who will own and pay for these investments?

Many of the discussions at CREF 2017 with local governments, utilities, developers, and financiers centered around those two important questions. Larger islands, like Jamaica and Dominican Republic, have already implemented various advanced storage systems. For many of the smaller and less developed islands, however, access to financing and resources is limited. But there are many banks and agencies (such as the Caribbean Development Bank and the Government of Canada—Global Affairs) willing to help.

Trusted advisors in both this sector and the region, along with energy experts, should unite to help these Caribbean communities on the path toward resilient, sustainable, and affordable power. 

  • Mike Voll

    Mike Voll has a deep passion for innovation and creative application of engineering principles.

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