“Save us, Elon! Save us!” a man shouted at the rosy-cheeked billionaire on stage. The billionaire was Elon Musk, a passionate futurist and crusader for renewable energy. The visionary Tesla founder took to the stage at the electric car company’s Hawthorne, Calif., design studio last night to reveal the much-hyped “ missing piece” of our future. And, yes, it’s all part of his ambitious grand plan to save the Earth on his way to Mars, specifically from the environmental ills of oil and gas.

As predicted, Musk spilled the details at the glitzy show-and-tell about Tesla Energy, Tesla Motors’ new brand of sustainable battery systems for the residential, business and even public utility use. The offering -- a bold detour from the world of luxury e-car-manufacturing and into the mushrooming renewable energy market -- brings forth two products.

The first is the Powerwall, a home battery system, available at 10 kilowatt hours (kWh) for $3,500 or for $3,000 for 7 kWh. (Prices don’t include installation.) The second product, estimated to cost around $13,000 a pop, is the refrigerator-reminiscent, 100 kWh Powerpack, an infinitely scalable, utility-class industrial battery targeted to mid- to large-sized businesses.

“The issue with existing batteries is that they suck,” Musk quipped from the event stage to raucous woots and loud applause. “They’re stinky, ugly, bad in every way.” Not only are his much better, he says, “They’re beautiful.”

He has a point. They sort of are. The compact, 220-pound Powerwall models are stackable, rechargeable lithium-ion batteries encased in attractive outer shells that fittingly resemble shiny car hoods. After all, the tech inside is a derivative of the battery inside of Tesla’s Model S.

Powerwalls work with solar or grid power and provide backup power. Both versions, six slender inches thick, can be wall-mounted inside or outside of your house or garage. Available in white, black, gray, blue and red, the sleek, Internet-connected units are indeed pretty, but, uh, not enough to lick.

Musk told reporters at a press conference held just before the red carpet launch party that he’s confident the batteries hold the power to revolutionize energy consumption at a global level. He realizes, though, that that’s no easy feat and might seem a little out there.

“Our goal here is to fundamentally change the way the world uses energy at extreme scale,” he said. “It’s going to seem crazy, but you’ll see what I mean.” Not as crazy, perhaps, as putting a man on Mars this decade.

We asked the Canadian-American entrepreneur and serial investor to describe why the everyday homeowner would want a Powerwall battery. He pointed to its ability store energy to help users survive off the grid whenever energy is scarce or too expensive. “You’ll have the security, freedom and peace of mind of knowing you’ll always have power even if your utility goes down.”

The temperature-controlled batteries are especially beneficial for people who live in cold climates, he said, where grid power often fails during ice storms and other inclement weather.

Or, if you’re ready to ditch the grid altogether, Tesla’s Powerwall can help you cut the cord, that is if you have solar panels. “If you combine the battery pack with solar, you can go completely independent,” Musk said, “so you can be just free of the grid if you want.”

As for Musk himself, he’s not living off the grid just yet. Smiling and rolling his eyes, he admitted that he doesn’t own any Tesla Energy batteries yet. There are, however, several solar panels installed on his $17 million mansion in posh Bel Air, Los Angeles.

The industrial Powerpack has already gone on sale to select customers, including Wal-Mart and Cargill. As for the home batteries, they’re available for pre-order now and are expected to begin shipping in three to four months. Musk said he expects the home units to reach moderate volume production later this year, then to kick into “much more serious production” next year, when manufacturing them will transition to Tesla’s “Gigafactory” in the Nevada desert.