At the Hertz counter inside Miami International Airport, the agent was explaining the company's refueling policy when she suddenly veered off-script. "You don't need to hear this," she said apologetically. She picked up a yellow highlighter and scribbled out the inapplicable section on the contract, emphasizing the main point of renting a Tesla: to not have to fill 'er up.

Until now, travelers in the United States could not easily rent electric vehicles, which run completely on batteries. A number of major rental car companies offer hybrids, which derive electricity from gas, and Turo, a car-sharing site, lists privately owned Teslas. But in October, Hertz gave the EV movement a big push when it announced that it was purchasing 100,000 Teslas. Last month, the vehicles started appearing in booking searches, the first wave of a national rollout that will expand to more than 20 cities, including Washington, Philadelphia, New Orleans, Nashville, Las Vegas, San Francisco and Seattle.

"This is the trend. The Biden administration is talking about transitioning fleets to all-electric cars," said Marc Geller, co-founder of Plug In America, a nonprofit that advocates for EVs. "The Tesla-Hertz deal could help increase the adoption rate, because people can experience EVs beyond the test drive."

In February, the American Car Rental Association acknowledged its influence on "sustainable mobility." It noted that, on average, its members purchase one in eight new light-duty vehicles sold annually in the United States. In addition, rental car drivers account for a quarter of all road miles traveled in the country each year, it said. "The car rental industry likely is the most important shared mobility stakeholder for converting 'motor vehicle trips' by an individual to 'zero emission vehicle trips' — even more important than individually-owned vehicles," the association's statement read. However, ACRA said the industry and infrastructure need to develop more before EVs can become as mainstream as, say, the Kia Rio or Hyundai Accent.

"ACRA's primary concerns are whether renters will want to rent EVs in the future (concerns about range, charging infrastructure, etc.); whether the existing electric infrastructure at airports, where 50 percent of rentals occur, can support large numbers of EVs being charged in rental facilities at the same time; and whether EV rentals can be priced competitively with other vehicle options," Greg Scott, an association spokesman, told me by email.

The $1.2 trillion infrastructure bill passed in November could dispel some of these worries. The package earmarks $7.5 billion to build a network of charging stations and grants tax credits to companies that purchase EVs for commercial use. Rental car agencies could possibly pass along the savings to their customers.

In general, rental cars are not a bargain at the moment, due to a shortage of inventory and delays in the supply chain. Plus, as of Dec. 16, gas has been averaging about $3.32 a gallon, roughly a dollar higher than last year, according to AAA. When I booked a Tesla for my recent Miami trip, the daily rate didn't cause my eyes to bug out. The 2021 Model 3 cost $105, only $5 more than my last rental, a Dodge Charger in Nashville. In addition, Hertz is footing the bill at Tesla Supercharger stations through Jan. 31. Even without the promotion, the price of charging roughly equals a snack shopping spree at a gas station market. Based on my calculations, I would break even financially and triumph nutritionally.

I had my first EV experience a decade ago, in a Nissan Leaf that left me slightly traumatized: Watching the needle drop while stuck in Los Angeles traffic miles from a charging station was as panic-inducing as running out of gas in Death Valley. The EV industry has grown up exponentially since then, but to be safe, I called Marc for driving tips. He assured me that Teslas were built for novice EVers. (Note: Tesla has been dogged by safety issues. Recently, a Paris taxi company temporarily pulled its Tesla Model 3s from its fleet after a fatal accident involving an off-duty driver. Police are investigating. Early this year, the National Highway Traffic Safety Administration concluded that more than 200 acceleration issues were caused by drivers mistaking the pedals rather than faulty design.)

"Tesla is the right car for a rental agency to use. The learning curve is not very steep," he told me while he was cruising around Oregon in, yep, a Tesla. "It has a complete ecosystem. You can use Tesla Supercharger stations, which you can find on the screen. It could not be any simpler."

I told him that I typically fuel up at a quarter of a tank and fill it to the brim. Do the same rules apply? He said that I could safely go down to 20 percent and that the charging process slows at the 80 percent mark. "There's an advantage to charging when it's lower," he explained. He suggested that I choose accommodations near a charging station or with access to an outlet, so I could feed the battery while I was sleeping. As an example, he said he had booked a room in a motel in an RV park with 240-volt hookups in Garibaldi, Ore.

He encouraged me to reach out to other Tesla drivers while on the road, describing them as a supportive and enthusiastic community. And if I were truly stumped, I could always text him. "I am the Tesla whisperer," he said before the call dropped.

Hertz also swooped in to help, sending me several e-tutorials before my departure date. The mini-seminars included "Time to get techy in your Tesla rental" and "Are you ready to experience the rental rEVolution?" But not one, as far as I could tell, explained how to open the driver's door.

For assistance on the basics, I tracked down an employee in the parking lot and led him to the sleek, gray enigma in Space No. 216. He taught me how to turn the car on, lock it and charge it, which involved a trip to the trunk and a small black case packed with cords and adapters for non-Tesla charging stations.

Before setting him free, I double-checked the return policy. "It's really OK to bring the car back with only a 10 percent charge?" I asked him incredulously. It was, he said, adding that the staff just needed enough power to move the car from the drop-off point to its stall, a distance of a few feet.

My plan was to drive 160 miles to Key West, then motor back north to Key Largo for the night. The one-way trip should have taken just over three hours, but I lost a little time sitting in the parking garage, fiddling with the touch-screen device. (If you are traveling solo, take a moment to familiarize yourself with the technology. If you have a co-pilot, as I did, remind your buddy of their responsibilities as navigator, technician, DJ and emotional support human.)

My friend Christian plugged "Key West" into the GPS, which showed us how much power we would need to reach our final destination — about 72 percent. (We left the airport with a 91 percent charge.) To be safe, we added a stop at a Supercharger in Marathon, about 110 miles away. Once on the open road, I started peppering Christian with requests: Can we ... open the sunroof, play tunes, find an outlet for our phones? We discovered that the car did not have a sunroof or USB ports. Instead, it came with a glass rooftop that blocks harmful UV rays (ideal for a sun-blasted road trip) and a wireless charger in the center console (a much sleeker design than a tangle of cords). For music, Christian landed on "Caraoke." A message warned us that the written lyrics were for passengers; drivers could sing along if they already knew the words. We duetted on "Umbrella." During my Rihanna solos, he/Jay-Z played Solitaire on the screen.

The Supercharger station was visible from the road. I drove through the parking lot of the Florida Keys Marathon International Airport to a row of four terminals. I was soon joined by a Tesla SUV with a "Happy Birthday" message scrawled on the side and a sedan with mountain bikes strapped to the back. According to the computer monitor, we would need 15 minutes to continue our journey, but with no Superchargers on the final leg, we left the car for a longer boost and set off to forage for food on Overseas Highway. We returned 40 minutes later and, per the driver's rules, sat outside the car to eat our ice cream.

In Key West, we checked the charging opportunities on the off chance we could replenish the battery at a secondary source while gallivanting around Duval Street. I felt like Goldilocks on a quest for power instead of porridge. The first charger, at the Orchid Key Inn, was in use. The second, at the Mermaid & the Alligator B&B, was blocked in by cars. At the Ocean Key Resort & Spa, I followed the valet by foot through the lobby and into a covered garage, where he pointed out two chargers — for guests only. In my final attempt, I drove to the Hyatt Centric Key West Resort & Spa but was thwarted by a gate with an entry fee.

Fortunately, we would pass the Marathon Supercharger again en route to our lodgings at the Pelican Key Largo Waterfront Cottages. Not stopping would be as foolish as blowing by a free taco stand when you know you'll be craving a late-night snack. We parked beside a Tesla that two friends from Philadelphia had rented through Turo. One woman was sitting on the curb, chatting on her cellphone; the other was trying to understand why the car would not charge beyond 80 percent. While we helped her, she told us that she was the mom of twins and didn't have time to sit around and wait for her car to charge, even on vacation. In a traditional vehicle, she said, she could have made the two round trips from their hotel to Key West without stopping. I didn't think reminding her about "Caraoke" would improve her mood, so I simply cheered when her car's charge reached 100 percent.

From our accommodations, we could have made it back to Miami on the 62 percent charge. But I wanted to give the Hertz folks an extra cushion. We found a bank of eight Superchargers by Sonny's BBQ restaurant in Florida City. I squeezed between two identical Teslas. A car with New York plates pulled up. The driver was wiping down the exterior with a rag. I sidled over to chat, Tesla driver to Tesla driver. I asked him whether he drives his Tesla between the two states. He said that he does and that the route is heavily dotted with Superchargers. His strategy is to charge partially and more frequently. I asked him how low he has gone. "Three percent once," he said with pride. "But I've had my Tesla for three years."

Though I had barely a full day under my belt, I was growing bolder. In Florida City, I stopped at 80 percent. About 25 miles from the airport, Christian discovered that he could click on a destination on the map and connect to its website. He read me the description of By Brothers, a Cuban eatery with crafts vendors, a nursery and donkeys. Normally, I would ignore the temptation, my mind focused on finding a gas station near the airport. But with the Tesla, I pulled into the attraction, savoring my liberty from the pump and Hertz's refueling policy.