He cycles for conservation

Nathan Phillips hasn't flipped a switch in his Boston University office for nearly two months. In his zero-carbon office, energy is generated strictly by a solar panel and a bicycle.

Phillips burns calories, not carbon, while working on his laptop.

With his wife's Raleigh Passage 3.0 bicycle attached to a stand equipped with a small generator, and a large solar panel he installed in February, Phillips, 40, never uses the radiator, air conditioner, overhead fluorescent lights, or wall outlets. In fact, he has blocked all outlets and light switches with plastic covers to ensure that he won't accidentally turn on lights or plug in appliances.

For nearly two months, he declares with satisfaction, he has generated zero carbon dioxide, the leading cause of global warming.

The associate professor of geography and environment says he got the idea after working in places including Ecuador and rural New Hampshire, where centrally distributed electricity is unavailable.

Phillips has attached a small laptop tray to the bicycle, so he can power his computer by pedaling. As for the other bicycle propped outside his office door, he rides that the nine miles to work from his home in Newton nearly every day.

The solar panel and bicycle generator are both connected to a 12-volt battery, which stores all the electricity used to power his phone, a laptop, and two low-energy lamps. When fully charged, the battery can power appliances for up to 24 hours.

Since going zero carbon, Philips says he hasn't encountered any major problems, but is concerned about his heavy reliance on the solar panel, which in last week's overcast weather, for example, generated next to nothing.

Unlike many cyclists deterred by rain, Phillips uses his bicycle more in stormy weather; the more it rains, the longer he pedals. He can rely completely on the solar panel on sunny days, but must pedal for about an hour per day when it's overcast.

"I rely more on the solar panel than expected, because I sit at my laptop when I'm not cycling," Phillips said.

"Though I haven't run out [of electricity] in a month and a half, I would worry if there were too many overcast days."

The office is a work in progress, and Phillips already has a couple of improvements in mind. He would like to experiment with a reclining bike, and he is looking for a sturdier laptop tray.

Phillips estimates that he saves 2.4 kilowatt-hours of electricity daily, or roughly 26 cents per day. But he emphasizes that it is less about the cost of electricity and more about reducing carbon dioxide emissions.

"I save nearly 900 kilograms of carbon dioxide per year," Phillips said.

Because he manually turned off the central heating in his office, Phillips relies on sunlight and cross-ventilation to heat and cool the space. Even during a brutally cold week in late February, the heat stayed off.

"This is my temperature control," he said, opening and closing the window.

Phillips isn't sure if he will be able to remain off the grid during warmer months.

"I might need to break down and use the air conditioning in the summer," he said.