Unlike other sources of electricity, solar is a type of power that is flexible enough to fit into many kinds of spaces, from a sloping roof on a home to a field in the middle of the desert. The latest novel example of this is so-called “solar community garden,” which are solar systems that are community-owned and shared.

Community solar gardens ideally are located within a town or city limit and serve a bunch of residents who either pay to own a piece of it or subscribe to the project without owning the equipment. Electricity from the solar panels goes to the grid and is sold to the local utility, which then credits the sale to the owners or subscribers of the solar garden. The credits then show up on each of their utility bills.

The goal is to allow renters, or anyone who doesn’t or can’t put solar on their rooftops, to still benefit from localized solar electricity generation, which is encouraged by federal and many state governments through rebate and tax incentive programs.

“We think of it as owning a garden plot in a family solar farm,” said Matt Cheney, CEO of CleanPath Ventures, at the Intersolar conference in San Francisco last week.

What are the barriers?

A community solar garden isn’t common because many states and utilities don’t have policies in place that allow such communal ownership and credit-sharing of a solar system. What is more common is net metering, where a home or business owner can put solar on their roofs and sell any excess electricity at retail rates to their utilities. The sale shows up as credits on their utility bills. Net metering rules often tie the solar equipment to a particular utility customer’s account, so there is no sharing of the credits.

California is working on expanding net metering to renters who don’t own roof space for solar panels. Called virtual net metering, these tenants of residential or business complexes can share the credits from the sale of electricity from a single solar installation. Landlords also will be able to share the credits because they, too, are electric ratepayers on the premises (they pay for electricity that lights up the garage, hallways and other parts of the complex).

But virtual net metering requires that the installation has to be located on the premise. Not every rooftop has the space to accommodate solar panels. And landlords may not see enough incentives for them to bother with a solar system construction on their properties.

In contrast a community solar garden could be located elsewhere and on the ground instead of rooftop, and it could allow for a transferring ownership or subscription. It also should be cheaper to install because it’s likely to be larger than a typical residential rooftop system.

“You can sell that on Craigslist,” Cheney said. “You can give your friends a wedding gift of 250-kilowatt of solar capacity.”

Potential change in California law

Cheney used his talk at Intersolar to tout the California Senate bill, SB 843, that would make community solar gardens possible. The bill has made its way to the state Assembly and is waiting for its first hearing.

One of the discussions about the bill deals with how much community solar development owners or subscribers would get from selling electricity to their utilities, said Peter Olmsted, a policy advocate for Vote Solar, an advocacy group in San Francisco. Currently, the bill wouldn’t provide retail rates for the electricity sale, Olmsted said. The idea is that if you aren’t paying for the full distribution cost of bringing electricity to your home, then you aren’t entitled to get paid to offset that cost.

“We are trying to get our arms around how this would actually play out and if it’s going to create an attractive program for a broader community,” Olmsted said.

Political leaders in California and other states have touted small-scale solar generation as an important element of their plans to gradually replace power from coal or natural gas and cut greenhouse gas emissions. Installing smaller solar projects, that can be installed within urban or suburban areas, makes it unnecessary to build expensive transmission lines to ferry solar electricity from remote regions. Some solar power advocates also want more of this type of power projects instead of solar farms that require a large swath of land and often spark opposition from environmental groups.

Although community solar garden is a good idea, implementing it may not be so easy. There is still the issue of land availability – properties in large cities could be pricy, making a solar project economically unfeasible. What is the minimum size of a piece of solar system that a resident must pay for or subscribe to? If the minimum is set too high, then some people may not be able to afford it. Can people take their stake in the community solar garden when they move out of town?

Community solar gardens already are popping up in some places in the country. Two in Colorado have gotten some press coverage, including this 858 KW system that serves 350 people. The state passed a community solar garden bill last year. A Colorado congressman, Mike Udall, also has introduced a bill that would entitle community solar garden owners to take advantage of a 30 percent investment tax credit.

Researchers at MIT have figured out how to print photovoltaic cells on every-day materials like paper or fabric — and the process is practically the same is printing this article out on your desk printer.

MIT reports that a team of researchers has published a new paper in the journal Advanced Materials detailing how solar cells can be printed as easily and as cheaply as “printing a photo on your inkjet” thanks to new special inks.

“The sheet of paper looks like any other document that might have just come spitting out of an office printer, with an array of colored rectangles printed over much of its surface. But then a researcher picks it up, clips a couple of wires to one end, and shines a light on the paper. Instantly an LCD clock display at the other end of the wires starts to display the time,” reports MIT news. And indeed it does look basically that simple!

The paper solar cells can even be folded, and still be useful:

The new process utilizes a brand new technique of printing — it uses vapors instead of liquids, prints at cooler temperatures, and the printing is done in a vacuum chamber. The conditions for printing are easier on the substrates that create the solar cells, and they can be printed onto practically any old surface like untreated paper and even plastic.

What’s more, the printed cells hold up through significant use — the researchers printed a solar cell on a sheet of PET plastic then folded and unfolded it 1,000 times. The solar cell performed just as well as before it was folded at all.

Because the printing is fairly simple, and familiar in industries like packaging, the researchers believe the technology could be easily scaled up for commercial printing.

The new technology could potentially be good for the fashion designers who want to incorporate solar into clothing and accessories. Instead of a plastic-y, stiff cell on a messenger bag, the printed cells could be used and be just as flexible as if it were part of the pattern on the fabric itself. And more practically, the ability to print on paper and fabric means lighter loads for transporting solar cells, which translates to cheaper delivery of solar cells to rural areas in developing nations that need a reliable source of electricity. The printed solar cells can be coated with a laminate to protect it from the elements and still function just fine.

“We have demonstrated quite thoroughly the robustness of this technology,” Bulović says in the MIT article. “[W]e think we can fabricate scalable solar cells that can reach record-high watts-per-kilogram performance. For solar cells with such properties, a number of technological applications open up,” he says.

All of this sounds miraculous, but unfortunately, the printed solar cells only have an efficiency of 1%. That’s way below average. The team is working to improve the materials so that better efficiencies can be reached. It’s not quite ready for prime time, but it’s promising.

Solar Tracker

A solar powered system can be placed on your roof as a stationary system or it can be mounted on a pole. If you mount it on a pole, you can also place a solar power tracking device on it. This tracking device will ‘track’ or follow the sun as it moves around the curvature of the Earth.

It is known that a track racking system (also called a solar tracker) can get up to 40% more power. There are different kinds of tracking devices to help you increase the amount of power you produce.

You can compare costs of a solar power tracking device to an increase in the number of modules. Which would be better for you? Wouldn’t you like 40% more power?

To read the full article, please click here.

To your efficiency,

Robert Farbe

Institutes of higher learning are designed to energize and empower communities to reach a brighter future — but one school in California is taking that mission literally. For the very first time, a college in the United States has managed to not only go off the grid by producing their own solar energy, but to produce enough of the stuff to power hundreds of homes as well. And the best part of all, with the money they’ll save, educators can focus less on dollars and cents and more on teaching.

This week, Butte College in Northern California makes history by becoming the first college to become ‘grid positive’ thanks to its sustainable energy infrastructure of solar energy. The college boasts some 25,000 solar panels that can generate over 6.5 million kilowatt hours of electricity per year. All told, the clean energy produced at Butte is equivalent to taking 615 cars off the road, and is enough to power over 900 homes.

But of course, the benefits of a renewable energy infrastructure extend beyond reducing carbon emissions. By eliminating its energy costs, and by profitting from the extra energy put back into the grid, Butte College is on track to save an estimated $50 million and $75 million over the next 15 years, and that’s including the cost it took to install the solar arrays!

“Butte College has had a longstanding commitment to sustainability. Achieving grid-positive status marks the culmination of years of effort to build Butte College’s supply of solar power and to improve energy efficiency on campus,” said Dr. Diana Van Der Ploeg, Butte College president, in a release. “Having the support of the board of trustees, faculty, staff, and students was essential to making this achievement possible.”

With all those extra savings, Butte’s budget allotments that were once devoted to keeping the light on can now be spent turning lightbulbs on over its students’ heads. And thanks to the college’s forward-thinking example, perhaps those ideas will be of new ways to power the world.