The man who created the 5-hour Energy drink says he has more money than he needs—about $4 billion more. So he’s giving it away, spending his fortune on a quest to fix the world's biggest problems, including energy.

Manoj Bhargava has built a stationary bike to power the millions of homes worldwide that have little or zero electricity. Early next year in India, he plans to distribute 10,000 of his Free Electric battery-equipped bikes, which he says will keep lights and basic appliances going for an entire day with one hour of pedaling.

Bhargava, who dropped out of Princeton University after a year because he was bored and then lived in ashrams in his native India for 12 years, doesn’t stop at bikes. He’s working on ways to make saltwater drinkable, enhance circulation in the body, and secure limitless amounts of clean geothermal energy—via a graphene cord.

“If you have wealth, it’s a duty to help those who don’t,” says Michigan resident Bhargava, 62, in a documentary released Monday, Billions in Change, about his Stage 2 Innovations lab. “Make a difference in people’s lives,” he says, “Don’t just talk about it.”

Could his bike really work? Will people want to pedal for power? Could they afford it or even have room for it in their homes? It holds “huge potential and opportunity for rural households,” says Ajaita Shah, CEO of Frontier Markets, a company selling solar lamps and lighting kits in India. (Read about her work.) She says she’d like to test the bike with her rural customers.

“It’s so simple that we think we can make it for $100 … A bicycle repairman anywhere can fix it,” Bhargava says in an interview. Pedaling turns a turbine generator that creates electricity, stored in a battery. The first 50 bikes will be tested in 15 or 20 small villages in the northern state of Uttarakhand before a major rollout in the first quarter of next year. He says they’ll be made in India but doesn’t give details.

WATCH: See the trailer for the film Billions in Change.

Who Is He?

Bhargava’s a bit of a mystery man. He grew up in an affluent home with servants in India, but his family struggled financially after coming to the United States when he was 14. He worked odd jobs and got academic scholarships. “It was worth a year,” he says of studying math at Princeton. After a spiritual quest in India, he built companies, including Living Essentials, maker of the popular two-ounce caffeine shot that’s sold at checkout counters.

Though generally low-profile, he’s not without controversy. He’s sued to fend off copycats of his blockbuster product and countered challenges from state attorneys general for alleged deceptive marketing. The Center for Public Integrity dubbed him the “political kingmaker nobody knows,” saying he’s donated millions to mostly GOP political candidates via limited liability companies.

Also unknown: exactly how much money he has. The documentary says his net worth is $4 billion, but Forbes does not list him among America’s richest 400 people, which includes those with at least $1.7 billion. Bhargava has said it’s difficult to put a specific valuation on his private companies, but he’s signed the Giving Pledge, a Bill Gates-led challenge for the rich to donate their fortunes to charitable causes.

He says he didn’t want to “ruin” his son by giving him money. “I told him when he was 10, 'You’re not getting anything.' His attitude: 'Great. I want to do it on my own,'” Bhargava says about his now adult son.

Instead Bhargava has funded hospitals in India and his cutting-edge Stage2 lab in Farmington Hills, Michigan, begun in 2011 with former Chrysler CEO Tom LaSorda. “It’s the most well-funded playhouse for engineers you can possibly have,” lab engineer Kevin Moran says in the documentary.

Big Problems, Simple Fixes

Bhargava’s team has come up with innovative ideas in health, water, and energy. It’s pursuing Renew, a medical device that functions as an auxiliary heart by squeezing blood from the legs into the body’s core.

To address drought, it’s building the Rain Maker to convert 1,000 gallons an hour of any kind of water into drinkable water. Bhargava says potable water could be piped from offshore barges with this machine, now being tested at a desalination research facility in New Mexico.

He has an even grander idea—one aimed at nixing the world’s reliance on fossil fuels, which emit greenhouse gases when burned. Whatever people think of climate change, he says in the documentary, “pollution is a problem.” His answer: tap the heat from deep beneath the Earth.

While geothermal energy is already widely used in some countries, including Indonesia and Iceland, Bhargava takes a novel approach. Rather than using steam—mixed with chemicals—to bring the heat to the surface, he would instead pull it up with a graphene cord. He notes graphene, stronger than steel, is an incredible conductor of heat.

“You don’t need to burn anything…Once you bring [heat] up, you don’t change any of the infrastructure,” he says, explaining that utilities could simply distribute it instead of coal, oil, or natural gas.

“That’s going to be, in my mind, the final answer,” he says, estimating this type of geothermal could replace 85 percent of today’s fossil fuels. He says maps show half of the world has plentiful underground heat, and since graphene cables could run horizontally, they could route it to the other half as well.

“I think someone’s going to kill me,” he says with a laugh, noting how such an idea could upset geopolitics. He’s working with a graphene research center in Singapore to develop a cable and plans to have pictures available later this year.

The Bike Ridden Round the World?

Bhargava gets most animated when talking about his graphene cable, but he sees the most immediate potential in Free Electric. He says it could provide electricity for the developing world and offer post-storm backup power in wealthier countries.

View Images The stationary Free Electric bike has a battery to store electricity generated when the rider is pedaling. Its monitor shows how much the battery is charged. Photograph by Billions in Change

“This is going to affect a few billion people,” he says, noting the main challenge will be distribution—a subject he knows well. He won’t give the bike away, because he says people won’t take care of something that’s free. Rather, he’d prefer to incentivize distributors with profits. He says a village can also pool its resources, buying one bike but multiple batteries that can be swapped out to power individual homes.

Those working in rural India welcome the idea. “The problem of universal energy access is so big and diverse that we need multiple innovations to solve it...Free Electric appears to be one such product innovation,” says Piyush Mathur, chief financial officer of Simpa Networks, a company that offers pay-as-you-go financing for its solar lighting.

Others doubt the appeal of off-grid solutions. “The poor...want grid-based power like urban households that can run TV sets at the flick of a switch,” says Lydia Powell, senior fellow and energy expert at the New Delhi-based Observer Research Foundation.

Bhargava agrees “they want exactly what we want,” and he says his bike will help them make a living and take care of their families.

He says he wants to give them something useful, not buff his public image. “I want publicity for the project but not for me,” Bhargava says, referring to the documentary made by Film 45’s Peter Berg, who directed the 2013 war movie Lone Survivor. “There’s no purpose in being famous unless you have a hobby like Donald Trump. That’s his hobby.”

He also says he doesn’t see altruism in his philanthropy. “I like work,” he says. “It’s not giving back. It’s what else am I going to do?”

The story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.