The power grid of the future will require sunny skies above and energy storage below. Thanks to Tesla, Kauai has both.
When people ask Luke Evslin why he decided to live off the grid, he starts with the time he almost died.
Evslin grew up on Kauai, a nub of a former volcano at the oldest end of the Hawaiian archipelago, but he was living on nearby Oahu at the time of the accident, working and competing in races with an outrigger canoe club.
The biggest race of the year is a daylong ocean crossing from the island of Moloka’i to Oahu’s Waikiki Beach, which can take between five and eight hours. Exhausted paddlers rotate out of the canoe during the race, jumping into the water to be scooped up by a waiting motorboat. During the first switch, Evslin was getting ready to heave himself into the canoe when the motorboat struck him.
The propellor sliced across his back in five places, severing muscle and bone along his spine and pelvis, each cut a potential death blow. His teammates pulled him out of the ocean and rushed him to shore. Judging from the looks on everyone’s faces, Evslin wasn’t sure he would survive the hour-long trip to land.
“I wasn’t scared to die,” he wrote a month later from his hospital bed, “but I was sad to die. I realized how much I love our beautiful world and everyone that is a part of it … and I was sad that I’d only just noticed.”
Soon after, still recovering from his wounds, “I made the terrible choice to read Walden,” Evslin recalls. He came across these famous words from Henry David Thoreau: “I went to the woods because I wished to live deliberately, to front only the essential facts of life, and see if I could not learn what it had to teach, and not, when I came to die, discover that I had not lived.”
Evslin began dreaming of a self-sufficient life, in touch with nature and free of the careless consumption of modern society. He convinced his then-fiancee, Sokchea, to move to a rainy acre on his native Kauai, where they built an off-grid yurt powered by six solar panels and a bank of batteries.
They planned to use only their own energy, eat what they grew, and eliminate their carbon footprint. Luke even planted a few coffee trees, imagining he would keep up his caffeine habit guilt-free.
“I had this grand plan of being an example for people,” he says, “showing how easy it was going to be.”
He had good reason to think that. Bathed in Pacific sunlight year-round, Kauai has all the hallmarks of a renewable energy paradise. Others thought so, too. In 2008, the member-owned electricity cooperative set an ambitious goal to run the entire island on 50 percent renewable energy by 2023.
At the time, Kauai had no utility-scale solar at all. But by the final day of 2015, the island’s main power plant—a rusty sugar plantation-era diesel generator—shut down for the first time since firing up the 1960s. For a few hours in the middle of the afternoon, two large solar farms did the heavy lifting on the island of 65,000, and the diesel plant sat dormant.
It was a good omen. By the end of 2016, the utility was on track to hit its 50 percent renewable goal five years ahead of schedule.
This February, the co-op board voted to move the goalposts again: 70 percent renewable energy by 2030. It will probably clear that mark early, too.
But, as Evslin quickly learned, the path to a low-carbon future can be tougher than it seems. Even in Hawaii, the sun doesn’t always shine—and when it does, sometimes you end up with more power than you can use in the moment.
How to collect that solar energy, predict it, get it to the right places at the right time, save it up for a rainy day—those are the kind of challenges our massive, spread-out, and unevenly populated country faces as we make the switch to clean energy. It’s one of the reasons that Tesla is making a major investment on Kauai, hoping to get it right.
And it all comes down to a lesson that the Evslins learned the hard way: It’s not about getting off the grid. It’s about building a better one.
“I imagine that there will be a lot more failures than successes to report,” Luke Evslin wrote in the first post of a blog he started to document his life off the grid, on January 1, 2011. “But that’s the point of it.”
Evslin didn’t know just how much he would come to reconsider what counts as failure and what constitutes success. On a visit with the family this summer, I walk the property with Luke as he points out trees he had planted. He’s tailed by a handsome dog named Asher and a mismatched set of terrier mixes, Peanut and Pico. A calico cat appears and settles on the railing with a view of the yard, where ducks and wild chickens peck hopefully.
“I’ve failed at most things I’ve grown,” Luke says with a shrug. Other than the fruit trees dotting the property—supplying all the banana, papaya, breadfruit, and lychee the Evslins could want—little else has taken root. His attempts at arugula and tomatoes fell prey to the chickens, and the ducks discovered a taste for sweet potato; other crops didn’t take to the damp.
“The only real success I’ve had is taro,” Luke says. An easygoing, water-loving crop that can be regrown from its own stem, taro makes up the bulk of the calories the Evslins get from the land. Their one-year-old daughter, Finley, subsists largely on homegrown poi. For Luke and Sokchea, the grocery store remains a necessity.
Then there’s the water. Their water tank, which collects rain from the hill above the yurt, also provides a welcoming home for mosquito larvae. The tank’s lining recently sprung a leak, so the family has been living on jugs of municipal water hauled from Luke’s sister’s house. At one time, Luke might have thought of this as a betrayal of principle; now it’s mostly just inconvenient.
But the biggest problem for Luke, like the utility that serves his island, has been the sun itself. He and Sokchea scaled back their lives to live within their solar-powered means—ditching their toaster and microwave, giving up laundry on cloudy days when their batteries wouldn’t be able to recharge. But they still have rainy weeks where they run out of power and have to run their gas-powered generator to keep the refrigerator from spoiling.
Most days, however, produced more solar power than they could use or successfully store in their batteries. If they were connected to the grid, Luke thought, that power could be used by his neighbors.
It took about a year for Luke to regret his move off the grid. “It’s not that it wasn’t what we expected,” he explains. “We wanted the difficulty of it.” But he also wanted to show people it was possible to live with a smaller carbon footprint; instead, he was burning gasoline and watching the island’s electric utility outpace him, installing solar power and cutting carbon all over the island.
“That was all happening, not because of me,” he remembers thinking, “but despite me and my efforts.”
Just after 10 a.m., the sun comes down hot on Kauai’s biggest solar field. Rows of darkly gleaming panels ripple toward a horizon of jungle-green mountaintops and whipped-cream clouds.
By high noon on the sunniest days, the Kauai Island Utility Cooperative generates 97 percent of its energy needs from a combination of three large solar fields, residential rooftop solar, biomass, and hydropower. Last year, 42 percent of the electricity used on island came from renewable sources.
In fact, Kauai is capable of generating so much energy from sunlight that any additional solar power the utility installs would likely go unused much of the time. Unlike the mainland United States, where a massive power grid connects far-flung regions, Kauai has nowhere to send the power it doesn’t use—and right now, it’s got about as much solar power in the middle of a day as it needs.
Yet even on the brightest day, the utility’s diesel-fired power plants start chugging back to full speed as the sun sets. It’s the solar version of feast or famine. And it’s why, despite all its advantages, Kauai is still a long way from complete clean-energy conversion.
That’s where the ranks of industrial, refrigerator–sized boxes lined up beside the solar field come in. Grouped together on neat concrete pads, only the occasional Tesla logo hints at what lies inside: batteries.
In March, Tesla cut the ribbon on this groundbreaking grid-scale battery installation, a key test of the viability of energy storage in making renewable energy a more reliable part of the grid. With 50,000 solar panels and 272 batteries, the combined solar-and-storage plant provides enough energy to power 4,500 homes for four hours.
If Tesla can help keep Kauai solar-powered around the clock with its batteries, then it can apply what it has learned elsewhere in the country, and around the world.
On this particular sunny day, Tesla engineers are doing some final tests before signing off on the plant. The site manager unlocks the front panel and swings the door open to reveal lithium-ion battery cells stacked like cafeteria trays.
Much of this hardware was borrowed directly from the electric cars that Elon Musk built his company on. (The coolant reservoir fastened to the door looks especially automotive.) Decades of research and development into smartphones and electric cars make lithium-ion batteries the most reliable and cheap battery on the market today.
“We designed the Tesla plant to be like a conventional power plant,” Brad Rockwell tells me. He is the head of power supply for Kauai’s utility cooperative, the one in charge of balancing supply and demand.
“I can say, ‘OK, give me 5 megawatts on the grid,’” Rockwell says. “And the plant looks around and says, ‘Am I getting any solar? What do you know, I’m getting 7 megawatts of solar—the grid only needs 5, so I’m going to give them a solid 5, and 2 will go to the battery.’”
He moves a pen across a sheet of paper to underline the shifting arithmetic. “Then when a cloud comes over and the [solar panels are] only putting out 2 megawatts, now I need 2 from the solar and 3 from the battery. And it just does that all day long.”
Rockwell is a former U.S. Navy engineer, familiar with photovoltaic and battery systems because he studied them in the early 1990s. “It turns out that most remote islands are powered like ships are,” he says. Neither can rely on copious cheap fuel, and they can’t afford to waste what power they do have.
Most places, including Kauai, see two big, predictable peaks in energy use every day: one in the morning, when most people are waking up and getting ready for work, and a bigger one at night, when they return home. Both of those peaks occur outside the period when most solar power can be generated.
That’s why “there’s a finite limit” to how much solar power Kauai can consume right now, Rockwell says, showing me a graph of energy use over the course of a day. Between 10 a.m. and 4 p.m. on most days, Kauai nearly reaches its 100 percent renewable goal. Rockwell points out a gap of only a few megawatts between solar supply and the total electricity demand during the daytime hours, represented on the graph as a slim gray wiggle of conventional power under a heap of solar power.
“We’re already adding that much in rooftop solar every year. But,” he goes on, “if we can keep adding projects that don’t have to deliver here,” he taps the sunny yellow hill, “then we can start to erase this stuff,” he says, gesturing to the twin peaks of dark gray conventional power book-ending the day. “And that’s how we get to 100 percent renewable.”
Now that the Tesla battery plant is up and running, the utility will be able to cut 1.6 million gallons of fuel use per year. That power will come right off the top of the morning and evening peak demand. Because those peaks are also the most expensive times to generate power, Kauai’s customers should see a drop in their electric bills, too.
The co-op is already looking to its next solar-plus-storage installation, this one in partnership with the energy company AES. Announced in January, the AES plant will be about twice as big as the Tesla plant, and will supply 11 percent of the island’s annual electricity needs by the end of 2018.
By 2025—three years ahead of their latest goal—the utility expects to get 70 percent of its annual energy from renewables, much of it stored in those battery packs for use during the evening and morning peaks.
In June, Hawaii became the first state to formally adopt the Paris Climate Accord, in the wake of President Trump’s announcement that he planned to pull out. The mayor of Kauai, Bernard Carvalho, also threw his support behind the agreement.
“Although Kauai is a small island,” Carvalho said, “we believe it is our responsibility to take a leadership position on climate change mitigation. And we are strongly committed to staying on course to build a more sustainable and resilient future.”
But what will that future look like? It’s increasingly clear that it won’t be the off-the-grid Eden that folks like Evslin once imagined. Personal solar panels and other attempts to live the virtuous life look outdated in a place like Kauai, where the utility is committed to cutting carbon and costs at the same time.
The economies of scale are such that Kauai’s utility cooperative can install a solar-and-storage unit for about half what it would cost a family to install the same amount on a house. Even when it comes to the island’s fossil fuel–generated power, the utility can produce more from a gallon of gasoline than someone with a $100 generator in their basement.
Relying on personal power, Rockwell says, is no way to power a community, let alone an island.
This became obvious to Evslin midway through his yurt experiment: Inefficiency is the ultimate downfall of any individual effort to address climate change.
“Either you’re wasting electricity in a closed system, because it’s sunny and your batteries are full, or you don’t have enough power and you gotta run your generator,” Evslin says. “That’s not a bug in my system. That’s a feature of any off-grid system.”
These trends mean incentive programs set up to encourage homeowners to install solar panels are now out of whack. Hawaii’s public utility commission still requires Kauai’s utility to pay early solar adopters for power they generate, based on “avoided cost of fuel.” But these days, the power that’s being avoided doesn’t come from fossil fuels—it’s being provided by the island’s solar farms.
So although the utility is offsetting some panel owners’ bills for their (less efficient) solar power, the rest of the utilities’ costs (like batteries) are divided among members who don’t have access to rooftop solar power. These are the kinds of policy disincentives that Hawaii and the rest of the country will need to take into account as renewable power scales up.
As the island around them goes solar, Luke and Sokchea are looking at houses—they’ve tentatively picked one out—that would put them back on the grid, and back in a community they could feel a part of. If they lived in town, they could cut down on a huge chunk of their remaining energy use by walking or biking to work, or to run errands.
Still, they both admit they are reluctant to leave the yurt. Settling onto the couch with their dogs in the evening, Finley sleeping in a crib on the other side of their single large room, Luke and Sokchea weigh the pros and cons. They could shell out several thousand dollars to the utility company to hook them up to the grid out here, sure, but they’d still be left with many unanswered questions.
What about the benefits of neighbors, a little lacking out here at the end of the road? What about walls, which might come in handy as Finley gets older? It’s still beautiful here, but it’s no longer the dream it was when they moved in.
The experience taught Luke a lot. He learned first-hand the challenges of solar power—how cheap it seems when he needs to run a fan in the middle of the day, how expensive when he’s rationing out the last watts in his batteries.
By retreating to his hideaway, Luke came to understand the power of civic participation. He’s pursuing a masters in public policy online, and it’s not hard to imagine him—wry, self-deprecating, easy to talk to—running for a seat in county government, or maybe even on the utility board.
“The solutions to all of this can’t be individual,” he says—and by “all of this,” it’s clear he’s thinking about the challenges facing society as a whole, not just Kauai, not just energy.
Walking me out past the taro patch, back across the swinging bridge that spans the creek surrounding his property, Luke points out one last thing. “It’s funny,” he says, “it was only recently I learned that Thoreau had his mom bring him food out in the woods.”