Watch Tesla Flex: Tesla powers homes… and islands.

by Anna Gretz
November 28, 2016

Tesla’s Powerwall home battery took the residential energy storage market by storm in 2015, sending energy-conscious homeowners clamoring toward the new tech in droves. One customer, Brian Gilmore, took advantage of the Powerwall home battery as soon as he could, and he’s been very happy with the results.

In Gilmore’s words, the “Powerwall is a thing of beauty.” He has reported flawless and seamless energy storage from his solar panels since it’s installation earlier this year. Because the Gilmores have solar panels installed on their roof and the Powerwall allows them to store all of the electricity they generate, their household is able to run on 98% solar power. Effectively, they’re off-grid.

Off-grid living used to mean a ton of sacrifice… and dealing with a lot of darkness. Tesla, and other companies working to develop residential energy storage solutions, have completely changed the way people think about renewable energy, and independence from the power grid. Homes like that of Brian Gilmore now enjoy off-grid independence without really changing their lifestyle much at all.

Tesla’s Powerwall is showing people the real potential of solar power. But powering a home? That’s no big deal compared to Tesla and SolarCity’s latest project. This time, they’re powering an island.

Just one announcement in a line of many exciting developments, Tesla announced that they will be hooking up the entire island of Ta’u, an island in American Samoa, with solar power. Until now, Ta’u ran on diesel generators, burning a ton of fossil fuels to wire up electricity for the island’s occupants. Over the past year, Tesla has created an entire microgrid of solar panels and lithium island batteries that will supply power to Ta’u’s 600 residents.

Tesla is going to show the world solar’s true potential.

Not only that, but the Ta’u project will show customers and shareholders the potential benefits of Tesla’s acquisition of SolarCity. For this project, SolarCity supplied 5,328 solar panels, and Tesla supplied 60 Tesla Powerpacks to store all of the generated power. Even without sunlight, these solar panels and Powerpacks could fully power the island for three days, recharging fully every seven hours.

This means that Ta’u’s homes won’t be the only entities powered by solar. Businesses, hospitals, police offices, and fire stations will all use solar power as well. The project was funded by both American Samoan and US authorities to offset the more than 100,000 gallons of diesel the island was using per year (not to mention the cost of shipping all of the fuel in.) Escalating fuel and transportation costs were making this a non-sustainable way for the island to operate. Now, not only will the financial burden be lessened, but the carbon footprint will virtually disappear.

“Living on an island,” says Keith Ahsoon, a resident of Ta’u, “you experience global warming firsthand. Beach erosions and other noticeable changes are a part of life here. It’s a serious problem, and this project will hopefully set a good example for everyone else to follow.”

The first to follow may be the island of Kauai, Hawaii.

Kauai will be the next site of a huge, one-of-a-kind solar and storage project being built by Tesla and SolarCity. The project won’t be finished until early next year, but the site is already looking impressive with 55,000 solar panels, and a fleet of lithium-ion batteries.

The island of Kauai already uses an impressive level of solar power, but the local utility, Kauai Island Utility Cooperative, had been turning to fossil fueled generators in the evenings when the sun went down. Now, thanks to Tesla batteries, the cooperative can simply turn to the new solar farm to supply power instead of generators. This is the first time that a local utility has used a solar + energy storage system to replace generators and other fossil-fueled power plants.

Kauai isn’t huge, but the 33,000 customers of the utility cooperative dwarf the population of Ta’u. This Kauai project will take another stop forward in showing the world what solar power and energy storage is capable of. The vulnerability of the power grid has sent many utilities (as well as their customers) looking for new ways to use reliable, renewable power sources to strengthen and distribute the grid. Solar alone is not the answer--the KIUC can attest to this.

The island of Kauai has a lot of solar. A lot. Much more penetration than any of the other united states. On sunny, cloudless days, the island gets a peak energy load of 90% from renewables, and sometimes 70% from solar alone. A lack of solar is not the problem. In fact, the island can’t even handle any more solar unless they add energy storage. What the island really needs is to be able to store energy to be used at night, or even when clouds cover the solar panels generating power around the island. Kauai needed energy storage… and they needed it to cost less.

The cost of solar panels is currently at an all-time low, and battery costs have started to drop as well. A lot of this has to do with electronic companies investing in battery production. Even more of it has to do with the construction of Tesla’s Gigafactory in Nevada. The batteries used for the Kauai project were manufactured at Tesla’s massive Gigafactory. Low battery costs will prove to be a game changer for clean energy around the world, whether it’s coming from solar or wind. The major glitch in using renewable energy sources is that they’re inconsistent. In fact, they’re reliably inconsistent. We know that the sun is going to go down, and the winds are going to change. The simplest and best way to solve renewable energy’s intermittency problem is to use batteries that can store excess energy during the day, or when winds are strong, to be used when it’s still and dark.

Energy storage, in the form of batteries, completely changes the feasibility of using renewable energy as a power source. Together, solar and storage can keep the power flowing all the time. This is why Musk said merging SolarCity, a solar panel manufacturer, and Tesla, one of the leading producers of lithium-ion batteries, was “blindingly obvious.” Solar and storage are better together.

We’re excited to see where Tesla will take renewable energy next.