That is the vision articulated by automotive executives, shade-tree Prius hackers, Department of Energy officials and-especially-budding battery impresarios such as Ric Fulop. To hear Fulop tell it, electric motors powered by li-ion batteries are the future. Specifically, his batteries. Fulop is always excitable, but he really starts to rev up when the talk turns to plug-in hybrid electric vehicles, or PHEVs—and he makes sure the subject comes up often. Then he tends to cut loose with a "Dude!" As in: "Dude! We're getting 7000 charge cycles." Or: "Dude! Have you driven an electric car?"

Fulop, age 32, is a vice president at A123S.ystems, a Watertown, Mass., purveyor of li-ion batteries that hopes to capture a sizeable chunk of what could turn into a $6 billion PHEV battery market. An MIT graduate, Fulop co-founded A123 in 2001 with a $100,000 grant from the Department of Energy. Today, his company is the sole supplier of li-ion batteries to Black & Decker and is working with automakers to develop a mass production PHEV. Unlike conventional hybrids-say, the Toyota Prius or Ford Escape Hybrid, these vehicles could be charged from a home outlet and then driven for up to 40 miles on electricity before the gas engine ever turned over. Now, A123 is locked in a race with a handful of other firms filled with young, caffeinated Ph.D.s geeking out over cathodes and anodes and lithium in an attempt to engineer the biggest shift in car technology since the advent of the combustion engine.

This community of go-getting chemists and engineers got an adrenaline infusion in January when General Motors unveiled a plug-in concept car at the Detroit auto show. With its angular lines, sleek interior and 120-mph top speed, the Volt-meant to show off a new PHEV system called E-Flex-was inspiring. It was the first hybrid to suggest that efficiency can offer more than the smug satis­faction of virtue; it can be downright fun. "Dude!" Fulop says. "This is gonna be so huge!"

Finding an Outlet

Today, there are more than 230 million cars and trucks in the United States, of which maybe 700,000 have some form of electric motor to help drive the wheels. That's one-third of one percent-hardly the makings of an electric-car revolution. On the other hand, whether they focus on focus on hybrids, pure electrics, hydrogen, ethanol, clean diesel or another concept, nearly every carmaker is betting R & D dollars that conventional powertrains soon will face real com­petition from more efficient, climate-friendly technologies.

The PHEV's main selling point is big fuel economy, using technology that's almost ready now. While hydrogen, in par­ticular, would demand new infrastructure on a grand scale, plug-ins rely on 110-volt home powerlines and pump gaso­line. Tinkerers such as Felix Kramer, founder of PHEV advocacy group California Cars Initiative, already get 100 mpg on 55-mile trips using cobbled-together PHEVs.

Such fuel economy is within reach for anyone with a conventional hybrid, good mechanical skills and around $5000 to spend on parts-Kramer and friends are happy to help with advice and plans. Soon, drivers may be able to pay an aftermarket outfit to do the work. Both Hymotion, a Toronto company, and California-based EDrive Systems convert stock hybrids to PHEVs for fleet clients, at $12,000 a pop. The companies say they want to start offering the service to everyday road warriors-Hymotion by the end of 2007. Hybrids Plus, a new company in Boulder, Colo., hopes to start doing conversions by this summer.

Factory-built, dealer-sold PHEVs are another story. General Motors says both an E-Flex car and a Saturn­branded plug-in, called the Vue Green Line, will be ready by 2010. The Vue, like models on the roads now, will follow a "parallel" design, in which both an electric motor and a gasoline engine drive the wheels, often working in con­cert. In contrast, the E-Flex cars will be "series" hybrids. Only the electric motor will turn the wheels.

WATTS TO DRIVE?

Hybrid cars such as the Toyota Prius may soon be joined on the road by plug-in hybrids and pure electrics. Here are the specs on some distinct approaches to building such cars. The key figure may be the cost to go 30 miles, a typical U.S. round-trip commute. For comparison with a conventional gas-powered model, that figure for a 2007 Toyota Camry would be $2.83. Reported by Emily Masamitsu

The First Issue is Durability

Typically, makers of hybrid cars guarantee their batteries for at least eight years or 80,000 miles. In states that follow California's standards for Partial Zero Emissions Vehicles, the figures are 10 years and 150,000 miles. Those are high standards for li-ion batteries (think how poorly a three-year-old laptop battery performs) and it's hard to predict how long newly developed units will last. Small operations such as Hymotion can offer shorter warranty periods, but big caretakers want to bring vehicles to market that meet or beat today's standards. Then, there's the matter of safety.

Remember those exploding laptop batteries that made headlines last year? In a computer, a burning battery is bad; in a car, it's a disaster.

A123, which has a contract to develop a battery for GM, is not the only outfit reporting progress; Reno, Nevada-based Altair Nanotechnologies is shipping li-ion polymer packs to Phoenix Motorcars for the company's pure electric vehicles, which can travel 100 miles on a charge. (Currently, Phoe­nix, a small California firm, is selling to a few fleet custom­ers; it plans to introduce a consumer model in 2008.) Saft, a French company, is also working on a battery for GM.