Sajed Kamal with a solar cooker By Ashley Taylor On the weekend before the summer solstice – the longest day of the year – a Boston group that promotes solar energy hosted a celebration of the sun at the Community Growing Center on Vinal Ave. People came to discuss solar energy with members of the Boston Area Solar Energy Association (BASEA), finding ways to become less dependent on fossil fuels is a matter of global discussion. BASEA believes that solar energy could be one solution to the problem of diminishing non-renewable resources. According to Sajed Kamal, a member of BASEA's board, one hour of sunlight has enough energy to power the entire world for a year. Yet globally, he says, barely seven percent of electricity comes from renewable resources. "The potential is practically untapped," he says.

Somerville is no exception. The City has several renewable energy consultants and a solar consulting and installation company, yet solar power is not a significant source of electricity here. As Benjamin Mayer, of SunBug Solar, put it, solar energy use is "in its infancy."

The Somerville sun was brutal on Saturday. Sajed Kamal, who is on the board of BASEA and teaches at Brandeis University, demonstrated three kinds of solar ovens cooking a variety of dishes. A bowl-shaped solar concentrator, above which a pot can be hung, produced enough heat to light a twig on fire. A solar cooker made of cardboard covered in metallic paint could reach 250 degrees, and a Tulsi hybrid oven, which can also plug into an electrical outlet, used mirrors to heat several hot plates to up to 400 degrees. As a rule of thumb, Kamal says, the solar ovens take about twice as long as conventional ovens to cook a dish.

The Community Growing Center also showcased various devices running off electricity from solar panels. These panels are called photovoltaic systems because they use the energy of light to stimulate the flow of electrons and create electric current.

At the Growing Center, there are solar panels on the roof of the garden shed. Solar panels pump a serene fountain, called a peace sculpture, and circulate water in a pond, though that system is currently broken.

In addition to the Growing Center's photovoltaic systems, BASEA members also discussed their own residential systems.

Kamal and his wife, who live in Boston, have a 50-watt photovoltaic system on windowsill of their fifth-floor condominium. It is a stand-alone system, meaning that it is completely separate from the power grid. The four-foot-square panel does not produce a lot of electricity, but over time, it charges a battery. The Kamals then use the battery to power various devices including two 15-watt fluorescent lights, and the Tulsi hybrid oven. They would like to expand the system for their building. One reason they do not have a larger system is that their electrical provider, NSTAR, does not allow interconnection of the solar power systems with the grid where they live.

Henry Vandermark, the president of BASEA, lives in Cambridge and has a different kind of photovoltaic system, which is interconnected with the grid. His is system is 7 kilowatts – much bigger than Kamal's system. During the day, his solar panels produce more electricity than his home uses, and the additional electricity goes back to the grid, spinning his electric meter backward. At night, he uses electricity from the grid and buys back the electricity his panels generated during the day.

Though interconnection is not possible everywhere in Massachusetts, it is permitted in all parts of Somerville, according to Benjamin Mayer, of SunBug Solar, a solar energy consulting and installation company with an office in Somerville.

How much solar energy has Somerville tapped? Mayer didn't know exactly how much of Somerville's electricity is solar but said that "it's going to be very small." David Lutes, from the City's Office of Sustainability and the Environment, also thought it was probably "not a significant amount." Somerville High School has a 10-kW solar system. Lutes said that the City is "currently considering options to expand solar on other buildings."

The installation costs often deter people from solar power. Installing solar panels is a large investment. Mayer says that a 5-kilowatt solar system will provide electricity for an average-size home using 600 kilowatt-hours of electricity per month. A 5-kilowatt system costs $30 to $35 thousand to install. However, Mayer says, there are many state and federal rebate programs that reduce that cost by half. After the rebates, the solar system should pay for itself (in the form of saved electricity costs) within five years.

To people who think solar power is too expensive, Kamal counters that solar energy as cheap in comparison to oil spills and war, which he sees as the costs of non-renewable energy. He commented that, "The oil spill is a warning that we cannot be ambivalent about transitioning to renewable energy."