Donald Trump is a battery. This was first revealed last year, in “Trump Revealed,” a book by the Washington Post reporters Marc Fisher and Michael Kranish. “After Trump mostly gave up his personal athletic interests, he came to view time spent playing sports as time wasted,” they wrote. “Trump believed the human body was like a battery, with a finite amount of energy, which exercise only depleted. So he didn’t work out.”

When news of Trump’s voltaic nature surfaced again two weeks ago, in an article by my colleague Evan Osnos, health commentators rushed to emphasize that, no, in fact, the benefits of regular exercise are not fake news. But there’s a bigger issue at stake: If the President is a battery, what kind of battery is he? Nine-volt? Lithium-ion? Energizer? Coppertop? And, vitally, how much energy does this battery contain? How efficient is it, and how quickly is it being drained? Batteries from the hardware store sometimes have a label listing the minimum charge that they can be expected to deliver. This seems like the least bit of information that Americans should know about their President. Otherwise, how can we be sure that the Battery-in-Chief won’t run out on us?

Let’s begin with what’s inside. Last September, in an appearance on “The Dr. Oz Show,” Trump furnished a letter from his personal physician stating that he is six feet three and weighs two hundred and thirty-six pounds; that puts his body-mass index at 29.5, half a point below what the Centers for Disease Control and Prevention would consider obese. The average person is about sixty per cent water and mineral (mostly bone), so, minus the fat, Trump is ten per cent protein. By standard measures, a gram of protein contains four calories and a gram of fat contains nine. This puts the President’s total caloric content at about three hundred and thirty thousand calories, the equivalent of two thousand snack-sized bags of his beloved Lay’s potato chips. (Cooked, Trump might yield less.)

How is this huge store of energy being put to use? Minimally, it seems. For a man Trump’s size, an hour of golf burns about five hundred calories, on average—but Trump mostly covers the greens by cart, so his output is likely closer to a hundred calories. Quietly watching television burns a little over a hundred calories an hour, but lately Trump has been a more agitated and vocal viewer, so the activity might rank somewhere between fencing and punching a punching bag—say, six hundred and fifty calories. According to one formula, writing and sending a tweet burns 1.03 calories, so the Battery-in-Chief is expending one or two calories a day there, although last Friday, as he addressed concerns about his meeting with the Russians in the Oval Office (“The Fake Media is working overtime today!”), he expended ten.

As a voltaic cell, then, Trump is a largely untapped resource. How might one go about exploiting him? The field of piezoelectronics, which aims to turn kinetic energy into electrical energy, offers some general promise. One harvesting device, PowerWalk, fits around the knee, like a brace, and converts the motion from walking into a current strong enough to charge small batteries. (The U.S. military is currently testing it in the field, to lighten the load of soldiers and rescue teams in remote areas.) In 2015, Gil Zussman, a professor of electrical engineering and computer science at Columbia, and his colleagues published a study in which they attached small energy harvesters to volunteers, to see how much juice various activities produced. Spinning a swivel chair, for instance, generates about ten microwatts—six million people would have to do it to power a sixty-watt light bulb—as does taking a book off a shelf. “It’s not a lot, to be honest,” Zussman told me. “It’s certainly not enough to charge all of your electronics.”

In any case, harvesting kinetic energy from Trump could be difficult, given his limited interest in moving. His most vigorous exercise on the campaign trail was speaking at his rallies. “I’m up there using a lot of motion; I guess, in its own way, it’s a pretty healthy act,” he told Dr. Oz. “A lot of times, these rooms are very hot, like saunas, and I guess that is a form of exercise and, you know?” But whatever energy that costs him (sixty minutes in a sauna would burn maybe a hundred and eighty calories) far exceeds what kinetic harvesting can recoup. “How much energy a politician gets from waving his hands—that’s not an impressive amount, maybe tens of microwatts,” Zussman said.

A more fruitful approach might be to harvest the energy that circulates within Trump, “Matrix”-style. In recent years, scientists have made great advances in building tiny fuel cells that run on glucose, which is abundant in the human body. Rather than implant a traditional battery to power a pacemaker or other medical device, doctors can implant tiny flexible circuits packed with enzymes that strip the electrons from glucose molecules and funnel them into a proper electrical current. It’s like a miniature hydroelectric dam in the bloodstream.

“If you put one fuel cell in a strategic place in your body, it would put out very little current but could process all the blood in your body for a long period of time,” Sameer Singhal, a materials scientist and the president and C.E.O. of C.F.D. Research Corporation, told me. “You’d get a ton of energy, though not a lot of power.” Singhal conceded that extracting voltage of any real consequence from the human bloodstream would take more than one fuel cell, maybe dozens, at which point you’d have to consider “what you’re doing to the individual by artificially depleting their sugar.” Insuring that the glucose is continuously replenished would be essential; a second scoop of ice cream might do it.

For a battery, Trump is remarkably hostile to other batteries. His Administration is unlikely to increase the seventy-five-hundred-dollar federal tax credit given to owners of battery-powered electric cars, which would spur the nascent market. And he wants to roll back regulations on vehicle emissions, giving automakers even less incentive to build electric vehicles. Trump’s rush to ban electronic devices from airplane cabins would put more lithium-ion batteries, which have a record of catching fire when they overheat or short-circuit, in the cargo hold, contrary to the advice of the European Aviation Safety Agency.

What’s striking about Trump’s battery analogy is that it so blatantly disregards how bodies and batteries—all energy economies, for that matter—actually work. Yes, the years, the joules, every galvanizing essence, is ultimately limited. But these can also be recharged and revitalized. Trump instead views the world through the lens of non-renewability, a perspective that, increasingly, applies even to his tenure in office. At the end of the day, Trump will be judged as he judges himself—as a disposable battery, and one that leaks.