As more households in the Cayman Islands invest in solar, installing a home battery makes sense.

Homeowners in Cayman are about to have another option when it comes to renewable energy.

The Tesla Powerwall will soon be available on-island, a system that stores excess energy generated during the day.

“These will be the first such energy-storage systems in the Cayman Islands and among the first in the Caribbean region,” says James Whittaker, founder of solar designer and installer GreenTech Solar, the certified installer of the battery system. “It represents a turning point for renewables in Cayman, in many ways looking into the future.”

Powerwall is a rechargeable home battery system that stores energy from solar, wind or from the grid and makes it available on demand. It can power the home during the night or back it up if the electricity goes out.

The system serves as an instant generator for the home during an outage, which means the lights stay on, phones can be charged, work isn’t lost, and many other technology-related headaches can be avoided.

“They are a much better option for providing backup power versus a diesel or propane generator, and they also have a lower overall operational cost,” says James.

In short, a house battery not only lets homeowners be more power independent, but also reduces costs and puts less demand on the utility.

Sleek design

The Powerwall battery is compact and easy to integrate into the home and can be installed indoors or outdoors.

Scalable to as many as 10 units in sequence, the sleek, enameled rectangles designed with gently curved lines, come in deep blue, luxurious black, grey, signal red and “the neutrality of white with a touch of daring that only purple can provide,” according to one Powerwall review on, noting the glossy, violet highlights on the reflective ivory-hued surface.

The Powerwall – under initial development in 2012 and launched in 2015 – weighs 276 pounds; is 29 inches wide, 44 inches long and 5.5 inches deep; and has a capacity of 13.5 kilowatt hours, discharging 7 kWh when pushed to its peak and 5kWh continuously.

James says GreenTech has been designing its SunPower solar panel systems to accept the Tesla batteries.

“As such, all GreenTech existing customers are able to add the battery with no issues,” he says. “We can also retrofit any home or any solar system with the Tesla battery systems with some minimal design changes.”

The system costs around $8,500 to $9,000, which includes the battery, gateway, subpanel, design and installation.

Advanced technology

James notes storage technology has come a long way in recent times – dramatically improved by Seattle mega-entrepreneur Elon Musk, famous for his Tesla electric vehicles and now for his Powerwall storage units.

“Batteries have been around a long time but it’s just in the last few years with lithium-ion technology and the mass scaling-up of that technology that companies like Tesla have been doing that these systems are now economic and reliable for consumers,” he says.

“Early battery systems were typically lead acid or gel batteries. They were very unreliable; they required a lot of maintenance; they took up a lot of space; you often had to build a special ventilated room; and, overall, those systems had a relatively short shelf life.”

James anticipates high demand in Cayman for the Powerwall system.

“We expect to see hundreds of storage systems deployed here in Cayman during the next 12 to 24 months, starting in summer,” he says. “It makes too much financial sense not to do so and these batteries can provide a win-win situation for everyone involved including the local utility.”