Hibbard cautions against seeing the base as a site for random experimentation, of “just taking stuff and throwing it up against the wall and seeing what sticks.” Because it’s remote, and because importing goods and services is so expensive, the Navy engages in “a lot of analysis” ahead of time to figure out what might work.

But Guantánamo’s location — in the tropics straddling a bay — does make it fertile ground for innovations such as these:

•  Two Florida firms, Solar Source of Tampa and TerraSmart of Fort Myers, are the contractor and supplier of a 1,200-panel solar array behind the base high school, just below the scrubby nine-hole golf course. It should produce 430,000 kilowatt hours a year and power the base’s popular no-charge gym, which doubles as a hurricane shelter.

•  There also have been email exchanges about whether the base could grow algae, as biofuel, inside a floating field of wastewater discharged into Guantánamo Bay. “NASA scientists are exploring this technology,” says base spokesman Terence Peck. “No decisions have been made for experimental locations as of yet.”

•  In 2007, a Public Works officer bought a bioreactor off the Internet and tried his hand at extracting fuel from used cooking oil. It was abandoned after eight months, according to base environmental director Mike McCord, as too labor-intensive and potentially dangerous because of the chemicals needed for the conversion process.

•  The Navy put in artificial turf at Cooper Field, the outdoor sports complex, to save on the fuel for desalinating water for the baseball diamond and soccer pitch .

Guantánamo is also the first Navy base in the southeast region — stretching from Fort Worth, Texas, to Charleston, S.C., to Cuba — to introduce mock utility bills.

Since the military picks up the troops’ tab, the faux bills are meant to shock sailors and their families into conserving by estimating base household power costs. They come in at nearly 3.5 times the price of an average U.S. household.

The bills have had the desired “wow!” effect. Guantánamo human resources worker Ambroshia Jefferson-Smith felt her stomach turn in October when she got her $1,021.79 mock bill for a month of power at the single-story, ranch-style house she shares with her 15-year-old son, five television sets and a cat.

“It’s like coming home when you have been on holiday and getting that big credit card bill,” she said. “You don’t see anything tangible there, and you realize you have consumed a lot of electricity and water.”

By her estimate, the bill would be seven times the sum she would pay back home in Mississippi. So now she makes sure all the TVs are turned off, including the one on the backyard patio, and lowers the AC before she heads to work.

Conservation awareness is a work in progress. And the mock bills, like the Navy cops on bikes, are largely symbolic. The prison camps commander, the most senior officer on the base, has one of the biggest houses — and one of the biggest household bills: $2.093.67 in December, one of the coolest months in Cuba.

Another military unit here has joined the movement.

The Marine major in charge of the unit that monitors the 17.4 miles of fence surrounding the base agreed to let the Public Works department replace a third of the floodlights with solar-powered LED lights. They’re still on the electrical grid in case of too many gloomy or rainy days in a row. But they haven’t needed to use the grid yet.

“I don’t know what they’re doing along the Mexican border,” said Torley. “But the Marines were on board with all the energy stuff. They couldn’t tell a difference.”