The house looks like part of the landscape. “Sometimes deer and turkeys will walk right up onto the roof,” says Daryl DeJoy, owner of Penobscot Solar Design, speaking of the house he moved into last New Year’s Eve. And why wouldn’t they? The north side of the house rises seamlessly from the ground in a gentle slope with grass growing on it, just steps from the nearby trees. The house’s windows face south, opening up onto a patio where squirrels scurry to gather stray acorns.

DeJoy has been installing solar-powered electrical systems since 1988, and he’s lived on the same piece of land in North Penobscot for the past 16 years. To his immediate south is a six-acre hay field; the sun shines in through argon-filled windows fitted with insulated blinds to keep the heat in at night. At the side of the house, two large solar arrays provide all the electricity DeJoy will use, and provide it rain or shine.

He likes sharing his rural living space with the creatures of the woods. A Registered Maine Guide and the executive director of the Wildlife Alliance of Maine, he’s carved out a quiet yet comfortable home that also houses the office of his growing business.

“The domed ceilings are for strength,” he says, sitting in his airy living room beneath a fan that circulates the air. “There’s 600,000 pounds of concrete in this house. It’s a wonderful thermal mass. It takes a long time for the temperature in this house to drop, and it takes a long time for it to rise.”

DeJoy waited a long time to build the house because he doesn’t generally use credit, although he did take out a small loan “to make it livable.” In 23 years, he estimates that his small business has done more than 350 installations, from Maine to the Bahamas.

“One thing I believe in strongly is that a solar installer should live with solar power,” he says. “It qualifies you a little more to be an expert if you walk the walk.”

Though installing a solar-powered system in an existing house requires an initial investment that’s a stretch for many potential customers in this sluggish economy, DeJoy says there’s never been a better time to go solar. The price of equipment is dropping, and federal and state incentives can knock more than one-third off the cost.

Plus, sunlight is free, and guaranteed to be around for another few billion years, give or take a geological epoch or so.

All power is solar power, when you get right down to it. Oil and coal are the concentrated remains of animals and plants that flourished under the Cretaceous sun. Wind is the circulation of air caused by the sun heating the planetary atmosphere faster at the equator than at the poles. The tides are driven by the gravitational tension between sun, earth, and moon. And the sun itself is one big nuclear furnace, slamming hydrogen atoms together to make helium atoms, and releasing the missing mass as energy.

Approximately one two-billionth of the sun’s energy reaches the earth. But that’s more than enough to power the perpetual-motion machine that is our planet. Solar power, in its modern connotation, means using the earth’s share of the sun’s energy as efficiently as possible.

But it doesn’t have to be unduly expensive. “It doesn’t cost any more to build for solar energy than it does to build a conventional house,” says Floyd Severn, owner of Maine Solar, located in Starks. “But people are stuck in a groove. They still want multi-story boxes.” Dr. Richard Komp, president of the Maine Solar Energy Association agrees. “A passive solar home is cheaper to build than a conventional home,” he says. “You don’t pay extra for solar.”

Solar energy systems can be divided into two broad categories: those that use the sun’s heat directly, and those that produce electricity through the photovoltaic effect. Most people are familiar with passive solar heat and solar hot water heaters. These can range from simple to elaborate, and can supplement a heating system already in place or help to heat an entire house. In cold climates like Maine, solar heating often isn’t enough. DeJoy’s living room includes a wood stove in which he burns “bio-bricks” made of compacted hardwood. The cost to heat the earth-bermed home last winter was $260, including propane.

“I burn about a cord of wood a year for heat,” say Komp, who lives in Jonesport. Originally from Chicago, Komp earned a PhD in physical chemistry from Wayne State University in Michigan, and is the author of the book Practical Photovoltaics, which was first published in 1981 and has been updated in several subsequent editions.

Komp edits a quarterly newsletter, the Maine Sun, and has compiled a primer for Maine homeowners who want to use solar power. He spends several months a year in Nicaragua, where he is a visiting professor at the national engineering university in Managua. His house in Jonesport is “off the grid,” meaning that he gets all his electricity from the sun. “I haven’t paid an electric or heating bill since I moved here 23 years ago,” he says.

Komp spends much of his time in Maine (and elsewhere) hosting workshops on how to build inexpensive solar collectors using aluminum flashing, copper tubing, black paint, wood, and foam, making use of cells rejected by major manufacturers due to small imperfections. “Every part you can get from your local building supply store,” he says. “My house is becoming a solar workshop center.”

Because the electricity produced by solar cells is direct current and homes are run on alternating current, an inverter must be part of any solar electrical system. Some houses, like Komp’s, exist entirely off the electrical grid, using batteries to store energy for when sun doesn’t shine. Others, like DeJoy’s, are linked to the grid but backed up by batteries.

“When I started, 100% of the installations I did were off-grid,” DeJoy says. “Now, about 75% are grid-linked, and of those, about 25% have battery backup.” Batteries, though they add cost to a system, keep the household electricity running even during a power outage; DeJoy says he has about three days’ worth of electrical storage capacity.

Both Komp and DeJoy preach the value of conservation. Whereas the average Maine home uses 20-kilowatt hours of electricity per day, DeJoy’s house uses about seven. Because his system is grid-tied, excess energy he produces is dumped back into the grid. In some states—though not in Maine—homeowners can receive checks from the power company when they produce more electricity than they use.

“Before I ever talk with people about putting in solar, I first speak with them about energy efficiency,” DeJoy says. “One of the advantages of putting in grid-tie for people is that they don’t have to change a thing. But we strongly encourage them to change to more energy-efficient uses. I, for one, appreciate that the government mandated an end to incandescent light bulbs. Keeping them is like keeping Model Ts in production. We can do it better.”

He requires each potential off-grid customer to fill out a load evaluation sheet, detailing every use of electricity in the home. “It’s the single hardest part of my job,” he says. “It’s very simple, but boy, does it encounter resistance from people.”

From his laptop, DeJoy can monitor many of the systems he’s installed in real time. He can see readouts of how much shade is falling over each solar collector, how much electricity the system is making, and when the peak loads occur. He says he spends very little time on troubleshooting, concentrating instead on installing the system right in the first place.

“We first want to make sure it’s a good site,” he says. “We don’t want to just sell people solar; we want them to be happy with solar. I’ve been in business since 1988, and I’m very happy to say that my customers are my friends. I have people who are very happy with the work that we’ve done. Part of the secret to that is staying small and doing the job right the first time. If I had to live on service calls, I’d be very poor, because we have very few.”

You might be thinking that Maine’s winter weather has an effect on how much solar power can be harnessed from the sun. It does, but it’s not all together a hindrance. Ironically, a solar photovoltaic system is at its most efficient during the part of the year when the sun shines the least.

“It’s at its most efficient when it’s cold out,” DeJoy says. “At zero it’s tremendously efficient. It’s a physical property of silicon. We do a lot of work in the Caribbean in the winter, and it’s a huge consideration down there. I’m working on a 60-kilowatt off-grid system for a resort, which is going to involve 80,000 pounds of batteries, and I really have to consider that it gets 100 degrees there in the summer, and they run their air conditioning. The system really has to be oversized.” By contrast, the system in DeJoy’s house is 3.6 kilowatts.

Floyd Severn says that, even in a colder climate like Maine, rooftop installations can lose much of their efficiency because of radiant heat from the roof. For many homeowners, however, the roof is the only shade-free spot available. Severn recommends that panels be set three feet off the roof to minimize the loss of efficiency.

Despite the improvements in technology, solar energy is still dependent on the sun shining, which is why every solar energy proponent also preaches conservation. DeJoy’s house is spare but hardly frugal; a large refrigerator looms in the kitchen, and a stereo and home entertainment system are in evidence. Still, he doesn’t use electricity for any appliance whose primary purpose is to create heat, because it’s not an efficient use of the power he collects from the sun.

Komp maintains that the use of solar energy will become increasingly important as the effects of climate change become more evident. “The political climate is more important than the physical climate,” he says. He points out that Maine receives more energy from the sun than Germany, which leads the world in commercial solar energy development. “Germany is one of the worst places in the world for solar energy, yet there’s lots of it,” he says. “Arizona is one of the best places in the world, and there’s almost none, because the politicians there are all part of the carbon establishment.”

“Insurance companies and banks throw a lot of roadblocks in the way of solar development,” DeJoy says. “What they don’t understand, they say ‘no’ to.”

DeJoy is in his fifties, but his house will be around a lot longer than he will. Hunkered to the ground like a concrete bunker, it’s almost immune to damage from high winds and falling trees. A 60-millimeter thick pond liner covers the entire house beneath four feet of earth and five inches of foam insulation. The concrete ceiling is 10 inches thick. “This house should still be here 200 years from now,” he says.

It goes without saying that the sun will still be here, too.