Second of a two-part series. Click here for the first part.

SNOWMASS, Colo. -- Oct. 13, 2009, was the day when Stewart Brand -- a former guru to the environmental movement -- published his book "Whole Earth Discipline." It stressed the need for nuclear power to help reduce the risks of climate change. On the same day, his former friend and business associate, Amory Lovins, retaliated with a 20,000-word barrage on the Internet.

In two papers, one dense with data and footnotes, Lovins accused Brand of ignoring five of Lovins' earlier papers, making "unanalyzed and undocumented" claims, constructing "layers of fallacy," and indulging in "egregious speculation" and "sloppy scholarship."

Brand shrugged it off in later editions of his book. Lovins "doesn't just argue from details," he wrote. "He backs up a dump truck full of numbers and citations and dumps them on you, saying that if you won't master them, you can't possibly argue with him."

Lovins, now 65, was described by The New York Times in 1977 as "the enfant terrible of the energy left." He has been dumping data about energy and climate change on people for a long time. His targets, including Brand, admit that what is infuriating about Lovins is that, over time, he has often been right.

A young man with wild hair and thick, dark-rimmed glasses, Lovins first emerged as a national figure in 1976 when he wrote an article for Foreign Affairs magazine predicting that "we may well find climatic constraints on coal combustion" in a few more decades. He outlined what he called a "soft path" toward an energy future that stressed energy efficiency and solar, wind and other forms of renewable energy.

An American, Lovins had left Oxford University in early 1971, giving up a planned doctorate in physics because Oxford didn't consider his proposed topic -- energy -- a fit subject for academics. (It does now.) In the next five years, Lovins wrote five books for the U.S. environmental group Friends of the Earth. The "soft path" in Foreign Affairs soon appeared as part of his sixth book. He has since written 25 more.

He wrote his first papers on climate change in 1968, pointing out that generating electricity from coal and nuclear power plants raised two "existential questions." Burning coal could cause serious future climate problems, he predicted. And nuclear power plants could spread the technology and expertise that would allow nations to conceal nuclear weapons projects by disguising them as peaceful nuclear energy.

An unchanged 'mission'

In the 1980s, Lovins joined the Global Business Network, a California consulting firm founded by Brand, where Peter Schwartz, the chairman of the board, watched both evolving futurists working together. Brand, he recalled, was constantly changing his views on issues, but Lovins usually didn't budge. "Amory has had a mission to make the world much cleaner and safer. He has been driving with that vision since the 1970s relatively unchanged," Schwartz said.

Lovins did more than write papers and books. After he found that conventional engineering texts said building extra insulation into buildings rarely paid for itself, he built a 4,000-square-foot house here with thick insulating walls, insulated windows and vault-like doors. That allowed him to heat his home mainly with solar energy and save all of its energy costs.

It also allowed him to avoid buying a conventional heating system. He calls it his "banana farm" because it has an interior garden where banana trees grow big bunches of the fruit in the Rocky Mountains' sub-Arctic winters.

Since then, more than 30,000 so-called passive houses have copied his ideas, most of them in Germany and Scandinavia.

In 1991, Lovins was plunged into a debate over whether the U.S. auto industry could improve the fuel economy of automobiles. The federal National Research Council had decided to hold a mock trial in Irvine, Calif., pitting auto industry experts against advocates for cars that could get higher gas mileage.

"The only person we could come up with was Amory," recalled Ralph Cavanagh, who was the lawyer for environmental groups at the weeklong event. "Amory breezed in in his usual way, saying we can have 100-miles-per-gallon cars at competitive costs. He began showing them car designs. The auto industry was flabbergasted."

So was Cavanagh. He knew that Lovins had only three weeks to prepare for the event and hadn't done much work on cars. Lawyers for the car companies pounced on the witness, noting that he didn't have a science degree. Lovins retaliated with piles of studies and engineering data. "He [Lovins] has a way of talking about the future as if it was aimed in his direction. It drives people crazy," Cavanagh explained.

'Hypercar' spurs 'lightweighting'

The trial saw the birth of the "Hypercar," Lovins' concept of an ultra-lightweight, hybrid-electric car. It could get five times better gas mileage than the standard 1991 car. Just as the better insulation in his banana farm house allowed Lovins to eliminate a conventional heating system, the lighter car permitted a much smaller and lighter drive system.

Hypercar's body used carbon fiber, which was then an expensive, ultra-lightweight material used for fighter planes, rather than steel. Lovins made his car still lighter by throwing out the transmission, clutch, flywheel, axles, driveshaft, big combustion engine and starter. His drive system used fuel cells, small electric motors, batteries and software.

General Motors expressed some initial interest, but Detroit automakers were clearly underwhelmed by the idea of a hyper-efficient car. But others were more interested. Japan's Nissan awarded Lovins a prize, and Lotus Engineering in England worked with Lovins' research group, the Rocky Mountain Institute, borrowing lightweight concepts from Formula One racing cars.

Lovins decided to maximize competition among automakers by putting most of his concept into the public domain, so that it could not be patented. Critics said Hypercar was too small and radical to make it into American showrooms, so in 2000, Lovins and his fellow researchers came up with "Revolution," a sleek five-passenger SUV, refining many of his Hypercar concepts. It had half the weight of a conventional SUV but was capable of getting 114 mpg.

To build it, Lovins and his colleagues designed a new process of automobile manufacturing, using carbon fiber panels that could be snapped together to make the body. And he threw in more electronics. As one of his concept papers put it, "the Revolution is designed not as a car with chips but as a computer with wheels."

Although he has made several attempts, Lovins has been unable to get his car designs into production, but, prodded by new U.S. automobile fuel efficiency standards, the future of the auto industry is moving slowly, sometimes grudgingly, in Lovins' direction. Making cars lighter, or "lightweighting" them, is the new buzzword in Detroit.

Ideas beget more ideas

Overseas, carmakers are also moving toward him, but faster. In 2007, Toyota showed its concept car, the 1/X. It was a carbon fiber four-seat plug-in hybrid, and Nissan and Honda appear to be preparing similar cars. Two German automakers, BMW and Volkswagen, are scheduled to produce lightweight, super-efficient carbon cars using carbon fiber components this year, using a process that makes them much cheaper.

Lovins and what he calls his nonprofit "think and do tank," the Rocky Mountain Institute (RMI), have since focused most of their attention on improving the energy efficiency of buildings and electricity distribution systems. As Lovins argues in his most recent book, "Reinventing Fire," buildings are "energy hogs" that consume 42 percent of America's energy. "Much of that energy is simply wasted," he says.

RMI developed the concept and design for retrofitting New York's Empire State Building, which required the remanufacture of 6,514 windows, giving them better insulation. Lovins estimates the energy savings will pay back the costs in less than four years. Overall, he says RMI has helped design energy-saving systems for more than 1,000 buildings.

The onetime enfant terrible of the energy world has also helped Department of Defense planners calculate the real costs of projecting and protecting supply lines for fuel-guzzling fighting forces in places like Afghanistan. James Woolsey, former head of the Central Intelligence Agency, says he has enjoyed working with Lovins on a policy panel sponsored by the Defense Science Board.

"The thing that's good about a lot of his efforts is that he shows how much can be done with proper design and how much cheaper it is to save energy than to buy it," said Woolsey, who now runs a energy consulting firm in Washington, D.C.

What impresses Woolsey and other professionals Lovins has worked with over the years is that his interest isn't in making money. "If he patented everything he's come up with," Woolsey believes, Lovins "could be the CEO of an extraordinarily large company, but that's not Amory; that's not what he does. He plants ideas and then goes on and plants some more."

Lovins loves giving speeches to student groups, at which he sometimes sports a little bowl-shaped carbon fiber cap, molded in a new process that makes structures from carbon fiber more cheaply. Two years ago, in a commencement address at the University of California, Berkeley, he explained to the world how much climate change adaptation can be done through free markets.

He asked his audience to imagine a world where "carbon emissions have long been steadily declining -- at a handsome profit, because saving fuel costs less than buying fuel."

Rather than fear the future, he told the students, they could help make it if they apply and extend what they've learned and "take responsibility for creating the world you want."

The formula for that, Lovins told them, requires "chutzpah and humility, eager enthusiasm and relentless patience."