Stationary bike designed to create electricity Workouts on specially designed stationary bike generate electricity

David Butcher holds a light bulb he is generating power for from his PPPM, Pedal Power Prime Mover, at his him in San Jose photographed on Wednesday, June 25, 2008. From the pedal power it goes to a 1.5 Farad Audio Capacitor to an inventor and then lights the bulb.Photo by Eric Luse/ The Chronicle less David Butcher holds a light bulb he is generating power for from his PPPM, Pedal Power Prime Mover, at his him in San Jose photographed on Wednesday, June 25, 2008. From the pedal power it goes to a 1.5 Farad ... more Photo: Eric Luse, The Chronicle Photo: Eric Luse, The Chronicle Image 1 of / 7 Caption Close Stationary bike designed to create electricity 1 / 7 Back to Gallery

Like a number of highly motivated people, David Butcher starts every day with a workout. His poison: 45 minutes on a stationary bicycle.

Fitness is part of the incentive, but Butcher's primary motivation is a long-standing, and possibly obsessive, quest to generate his own electricity. So Butcher's stationary bike, which is wedged in a corner of his detached garage, is not your standard-issue exercise machine: It's a homemade power plant.

Butcher designed his ingeniously simple pedal generator for maximum comfort and efficiency: As the rider pedals, a wooden flywheel drives an electric motor, which generates an electric current that flows into a bank of salvaged lead-acid batteries for storage. A buried cable connects the batteries to a set of conspicuous orange outlets (denoting the off-the-grid energy source) in Butcher's home office, where he works as a Web design consultant. The orange outlets power several devices, including a computer monitor (but not the computer), cell phone chargers, a high-efficiency area light and a small Roomba robotic vacuum.

Last year, Butcher's electricity bill was zero. In fact, he pumped $150 worth of electricity back into the grid. But here's the catch: It wasn't the pedaling that did it. Although Butcher's daily workouts produce 1.8 kilowatt-hours a month, that translates into just 18 cents worth of electricity at today's rates - about 1 percent of his average monthly usage.

Instead, Butcher's energy-efficient house contributed 1,500 kilowatt-hours into the grid after a recent retrofit added photovoltaic panels to the roof.

His cedar-shingled bungalow on a quiet, tree-lined street in San Jose also makes use of skylights and other energy-saving devices, and it now produces far more electricity than it consumes.

"It's not a monetary payoff," Butcher says of his pedal project. "And if you want your pedal power to do anything meaningful, you have to run efficient devices."

Hence, Butcher's home is tricked out with both high-tech and low-tech energy savers:

-- Large windows in the rear of the house provide passive solar heating.

-- Devices called X10 modules kill electrical "vampires," such as microwave oven clocks and other "always-on" electronics. Remotely controlled by Butcher's computer, X10 modules (each outlet has one) turn appliances on and off according to when they're needed. For example, since Butcher doesn't run his dishwasher during the day, the computer doesn't turn on the dishwasher outlet until nighttime.

-- Suntubes (tubular skylights) illuminate the interior of the house during the day.

-- LEDs (light-emitting diodes) in lamps use even fewer watts than CFLs (compact fluorescent lamps).

Oil spill sparked interest

Butcher, who lives alone after a divorce, traces his environmental leanings to the 1969 Santa Barbara oil spill, which marred miles of coastline with 200,000 gallons of crude oil. Butcher was 14 at the time and witnessed it firsthand. He built his first pedal generator when he was in his early 20s.

"I was always interested in alternative energy and solar in particular," he says. "I was living in Portland, Ore., where solar is not as much of an option. So I thought, 'What else could I do?'

"I'd been on a swim team for years and I was in pretty good shape, and I thought there must be a way to get some power going."

Butcher's prototype bicycle was chain-driven and featured a welded steel frame. Today's version, with its simplified drivetrain and bolted frame, can be assembled with basic hand tools.

When he took up his pedaling regimen two years ago, Butcher tipped the scales at 180 pounds. Today, at age 53, he weighs a lean 150 and possesses a pair of legs that wouldn't look out of place on the Olympic cycling squad. Butcher's pedaling has become so efficient that he has pretty much abandoned his car (electric, incidentally) in favor of bicycling, reducing his carbon footprint still further.

Whenever people ask why he doesn't sell the pedal generator plans to gyms, Butcher's answer reflects his simple philosophy: "If you want to save energy, don't drive to the gym."

The combination of these positive impacts inspired Butcher to market the plans for his invention, and to date he's sold more than 300 sets of blueprints around the world.

Butcher built a second bicycle generator for demonstration purposes, with energy fairs - and, apparently, journalists - in mind. While his everyday pedal generator is set up to charge batteries, the exhibition model is tricked out with extras (an ultracapacitor, a digital meter and an inverter) to supply power to various devices directly. This way, riders can get a sense of how much physical effort it takes to power, say, a lightbulb versus a television set versus a coffeepot.

Although the two generators are similar in design, the exhibition model sports a sleek Plexiglas flywheel and dual electric motors. Wires connect the motors (inexpensive units used in electric scooters) to an ultracapacitor, which modulates the electrical current. A digital meter displays the energy statistics of each workout. An inverter changes the current from DC to AC, relaying it to several electrical outlets. Butcher designed the generator for maximum efficiency, which is key, because, as I was about to learn, generating electricity is a lot of work.

A cup of java

With Butcher's blessing, I hop on and start pedaling. I've been pedaling up San Francisco hills for 15 years, so how hard can this be?

Butcher instructs me to keep the output steady at 12 volts. I'm cruising at an easy clip when he switches on a compact fluorescent lamp. As the bulb winks on, the numbers fluctuate slightly on the meter readout, indicating an energy draw, but because the CFL is so efficient, it doesn't add any perceptible drag to the flywheel.

I realize there's something fundamentally gratifying about making your own electricity. You spin a wheel, a light goes on: It's magic. The fact that it's good for the environment is an added bonus.

After powering the CFL for several minutes I'm ready to up the ante.

"Want to try to make some coffee?" Butcher asks mischievously. He retrieves a pint-sized drip machine from the garage. As I charge up the ultracapacitor, Butcher fills the coffeemaker reservoir with water and throws the switch. I rev up the flywheel, preparing to blow the coffeepot away.

"Don't overreact," he warns. "Just gradually ramp up as it starts asking for more power." The voltage dips ominously on the readout. "Now, you won't really feel the draw until you try to start preventing that from dropping." The voltage slips: 11 ... 10 ... 9.

"Don't let that drop anymore," he cautions. The coffeemaker needs a constant 12-volt supply to do its thing. I pedal my way back to 12 volts and valiantly try to maintain it, but as the coffeepot's electrical appetite adds resistance to the flywheel, my leisurely ride begins to feel like an uphill sprint.

"Hold it steady," he says. Two minutes in, my legs are on fire.

"How's the coffee coming?" I gasp.

"Well, unfortunately, you've got to heat a substantial amount of water before the first drop comes out," he says.

At three minutes, I call it quits, wheezing like a mule with a punctured lung.

"No coffee for you," Butcher says sympathetically.

As I catch my breath, Butcher explains that heating water takes a tremendous amount of energy, and that without abundant, cheap electricity, we could all kiss our lattes goodbye.

Butcher already has. He brews his coffee cold, in a French press.

"It really brings it home to actually feel how hard you have to pedal to make something go," Butcher says, "and that's something that people will occasionally ask me on the Web site: 'So do you actually have to pedal harder when you're pedaling bigger things like TVs?' "

(I can testify that, yes, one does.)

"And it shows that the concept of work, that electricity is doing work as opposed to just being off or on, is not familiar to people."

CHAT WITH INNOVATOR

David Butcher broadcasts his morning generator workouts live on his Web site and responds to viewer questions as he pedals.

To see the pedal generator in action and chat with David Butcher, go to links.sfgate.com/ZEPA between 8 and 8:30 a.m. Tuesday-Friday.

-- To learn more about the pedal generator or to order a set of plans so you can build your own, go to links.sfgate.com/ZEPB. The site also features a resource page for teachers: links.sfgate.com/ZEPC.

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