Every 20 days, the sun bombards Earth with as much energy as is stored in our entire coal, oil and natural gas reserves. This clean and abundant solar energy is usually dismissed as too costly and inefficient to solve our nation''s energy needs. However, as fossil fuels diminish and prices rise, more and more people are getting turned on (flick!) to solar power.

This Saturday, some of these solar enthusiasts are hoping to shed light on the benefits of sun-based energy production. The Northern California Solar Energy Association (NorCal Solar) is sponsoring a tour of 70 solar-powered homes throughout the state, including four on the Monterey Peninsula; NorCal Solar''s parent organization, the American Solar Energy Society, is sponsoring simultaneous tours in 400 communities nationwide.

This will be the first year the Monterey Peninsula joins the tour. Led by NorCal Solar volunteer Greg Wolfson, the tour will feature technologies of varying price and design. Wolfson, who installed solar paneling on his home last April after attending a solar conference in Austin, Texas, beams with excitement about solar power.

"My goal is to make people aware of solar and alternative energies," he says. "There''s so much support on the Peninsula for living in synergy with our environment, yet sunshine is landing on everyone''s roof and very few have solar panels."

The largest single obstacle facing solar power may be price. But solar supporters like Wolfson argue that it''s really not that expensive when you take into account state tax breaks.

There''s the Solar or Wind Energy Credit System, which gives solar power owners a tax credit of up to 15 percent of their system''s cost. The Emerging Renewable Buy-Down program can also reduce system costs by up to 50 percent. Incentives like these helped to more than double California''s solar energy output between 2001 and 2002 and raised our state''s share of national solar power production to 85 percent.

Despite such breaks, installing solar power systems can still be expensive. Wolfson''s home, which will be on Saturday''s tour, cost $35,000 to equip with solar energy (a 3.8 watt system), even after a $15,000 Buy-Down rebate. He says his solar panels cost more than most, since they are fused to the tiles that cover his flat, 1920s-style roof. A four-person home could go solar for only $10,000, Wolfson says, but no system, can provide local solar-powered homes with complete independence from the energy grid in winter.

Photovoltaic cells, which make up solar panels and which convert sunlight directly into electricity using semi-conducting materials, can absorb invisible light through the Peninsula''s fog, but low winter sun and thick clouds limit their output. Although frugality and energy-saving appliances can help bring use levels down, there will still be gray days when residential solar installations will need utility energy.

There is a new program called "net-metering" however, that can help grid-linked solar homes compensate for these seasonal imbalances. Developed under Gray Davis, net-metering credits California solar-power users for the excess power they generate and deducts it from their grid energy use. So while Wolfson relaxes in his garden at high noon, using perhaps a meager 1,000 watts of energy throughout his entire home, the excess 2,000 watts his solar cells are producing is pumped out to the electric pole and fed to his neighbors. As the energy flows out, his magic meter essentially rewinds its counter, and with it, his energy bill.

Since installing his system in April, Wolfson has accrued a positive balance with PG & E and is waiting to see how far it will carry him, charge-free, into the winter.

Saturday''s Peninsula tour will visit four solar homes ranging from a simple $20,000 system to a home that Wolfson calls "mind-blowing." Located in Pebble Beach, Wolfson describes it as somewhat of an Apollo among solar homes, employing not just PV cells but also numerous aspects of passive solar heating. Passive solar utilizes architectural design to capture the sun''s energy--a technique used by the Anasazi Indians thousands of years ago.

The high priestess of this solar temple is Lee Von Hasseln, who describes her home without conceit or bravado. "I designed and built my house with solar in mind from the beginning," she says. "I have all glass walls, no fireplace to contaminate the atmosphere, and all bamboo cabinetry to conserve on trees. The house is oriented to the south so the sun comes in in the winter, but it doesn''t get hot in the summer because I have about a two-foot overhang." Her glass walls are 9 1/2 by 20 ft., 3/4-in. thick, and laminated with UV block to protect the interior. Her floors are made of limestone and act as heat reservoirs for the incoming winter sunshine.

"Of course it was expensive," she says, "but I did it because I believe in conservation. I''ve lived in California all my life, population is increasing and we have a need for more energy. I think it''s important to pay the difference to do things solar, and I feel that if more people do it the cost will come down."

That''s true, says Rob Swenson, the chief technology officer at solar energy company SolarQuest, but it''s not enough.

"If every solar cell that''s manufactured worldwide were shipped to Salinas, it would take 20 years until there were enough of them to create the energy to replace the Moss Landing power plant," he says. "Until someone steps up to the plate and makes a real factory, spending a billion dollars, then we''re just pussyfooting around."

Still, he continues, "the concept that a house has to be expensive to be energy efficient is nonsense." Swenson believes that if architects intelligently employ passive solar power in their designs, taking into account factors like which way the house faces and the Earth''s rotational patterns, enormous energy benefits could be reaped at virtually zero extra cost.

For Swenson, public ignorance plays as large a role in hindering widespread use of solar power as the lack of major government investment. "Prices are not going up fast enough to make the changes we need. The right price for gas is $10 a gallon; then people will pay attention to wasting the stuff."

At the recent World Summit on Sustainable Development in Johannesburg, Congressman Dennis Kucinich berated the US for refusing to shift $50 billion in fossil fuel subsidies to a fund promoting the use of solar energy. Considering that major federal investment is unlikely in the near future, the hope for solar energy may indeed lie in public awareness. This weekend''s tour shows the option is there for those far-sighted enough to see it.