by Martin LaMonica

Residential solar power is becoming more like a box lunch than a seven-course gourmet meal.

A number of companies are taking advantage of technical advances, notably microinverters, to make buying a handful of solar panels, rather than a roof full, a viable option. That doesn’t mean that everyone can install their own electric panels, but it can lower the cost of entry for solar.

Green Ray Solar this week is expected to announce UL certification for a solar panel that puts out alternating current, rather than direct current as most solar photovoltaic panels do today. AC panels can be simpler to install and wire together than traditional panels, which makes a piecemeal approach easier, said Miles Russell, the CEO of Green Ray Solar.

“Nothing could be more timely in a down economy than to do the right thing in a way so that it doesn’t kill the budget,” he said. “You can start small and add more over time if you desire.”

Green Ray Solar’s SunSine AC Module, expected for availability in the fall, is one of a growing number of solar photovoltaic panels that take advantage of microinverters. It’s a technology that has been pursued for years, but the reliability and efficiency have improved in the past few years.

Traditionally, solar panels are tied into a device called an inverter, which converts the direct current from panels into household alternating current. Strung together, several panels produce enough voltage to run an inverter which, sized for a rooftop array, is roughly as big as a computer monitor.

A microinverter brings that DC-to-AC function onto each individual panel. Proponents say the technology simplifies installation and improves panel performance. For example, shading on one panel will not affect the output of other panels connected to it, as happens with panels connected to a centralized inverter.

A full-size grid-tied solar array with about 15 or 20 panels can cost anywhere between $25,000 and $40,000 upfront depending on the size. AC panels are not cheaper, but proponents the modularity makes it easier to install a few panels, and then later connect more to the existing set.

More flexibility
James Cormican took the small-steps approach to solar at his parents’ home. Working with an electrician, he put five panels onto their garage, which was the only space with good sun available to them, for well under $10,000.

The advances in solar technologies in just the past couple of years give solar designers more flexibility to fit panels onto tighter spaces, he said. Whereas a full-size solar array will typically have a capacity of two kilowatts and higher, Cormican’s system is rated at one kilowatt, which is about enough to run a few power-hungry appliances.

“Of course there are economies of scale when you have many panels installed, but the argument that you can’t have a system with one or two solar modules is not true anymore,” said Cormican, who is an instructor at the AltE Store, which sells alternative energy gear to consumers and installers. He said the AltE Store is seeing more interest and business for smaller solar systems.

In addition to panels equipped with microinverters, thin-film solar panels put out a higher voltage, which gives people more flexibility in choosing inverters, he said. In Cormican’s case, the panels put out enough voltage to be tied into a traditional inverter.

Although the output and cost will vary depending on location, a one-kilowatt system will put out roughly 1,000 kilowatt-hours a year, and the installation cost is roughly $6 per watt, he said. Average electricity consumption in the U.S. is about 11,000 kilowatt-hours a year. Until 2016, solar installations receive a 30 percent federal tax credit, and there are often state incentives as well.

Cormican warned against people thinking that they can install panels themselves if they don’t have the qualifications of an electrician or solar installer. Although regulations and building codes vary by state, there are serious safety issues related to both grid-tied systems and solar systems with batteries. It might be difficult to find an installer willing to take on small jobs, but a do-it-yourselfer could possibly share some of the work with a pro, such as installing panel racking.

“If you can find an installer who is willing to work with you and let you do the parts that you are legally allowed to do–anything that doesn’t have to do with electrical work–then that can reduce the cost,” he said.

Plug and play?
The solar industry has been on a multiyear quest to lower the cost of electricity from solar with higher manufacturing volume and more efficient solar cells.

But because about half of the cost of a solar PV system is tied up in installation, a number of companies are trying to cut the installation cost, called the “balance of system” in industry parlance.

Andalay Solar, which is changing its name to Westinghouse Solar, developed what it calls a plug-and-play solar kit–available through installers and some Lowe’s home-improvement stories in California. There’s a panel, equipped with a microinverter from Enphase Energy, and a simplified wiring and racking system.

Similarly, Ready Solar offers a “Solar in the Box” kit designed for quick installation. Another company, Armageddon Energy, by the end of this year hopes to release the Solar Clover, which is made up of several small, hexagon-shaped mini-solar panels. The hope is to have solar installs done in a few hours and as easy as buying a kitchen appliance.

Earlier this month, Seattle-area start-up Clarian Technologies got a lot of media attention for its Sunfish, a do-it-yourself solar system designed for consumers to install themselves. Promised for next spring, it would include one or three panels, a microinverter that connects into a home power outlet, and a controller at the circuit board. As the company has not yet shown a product or gotten UL certification for safety, there is a good dose of skepticism among professional installers, said Cormican.

In addition to modularity, one of the big advantages of AC panels equipped with microinverters is that they can be individually monitored. The system from Green Ray Solar, for example, will include a solar panel from Sanyo equipped with a microprocessor to gather performance information and a microinverter. The kit, available through installers, will also have a gateway that connects to a home Internet connection, giving people access to solar data online.

“The information side of things is very rich territory,” said Russell. “It’s really revolutionary for the industry to have this kind of scrutiny.”

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Credit: US Air Force

Researchers have developed technology for large-scale solar power installations to self-clean.

BOSTON, Aug. 22, 2010 — Find dusting those tables and dressers a chore or a bore? Dread washing the windows? Imagine keeping dust and grime off objects spread out over an area of 25 to 50 football fields. That’s the problem facing companies that deploy large-scale solar power installations, and scientists today presented the development of one solution — self-dusting solar panels ― based on technology developed for space missions to Mars.

In a report at the 240th National Meeting of the American Chemical Society (ACS), they described how a self-cleaning coating on the surface of solar cells could increase the efficiency of producing electricity from sunlight and reduce maintenance costs for large-scale solar installations.

“We think our self-cleaning panels used in areas of high dust and particulate pollutant concentrations will highly benefit the systems’ solar energy output,” study leader Malay K. Mazumder, Ph.D. said. “Our technology can be used in both small- and large-scale photovoltaic systems. To our knowledge, this is the only technology for automatic dust cleaning that doesn’t require water or mechanical movement.”

Mazumder, who is with Boston University, said the need for that technology is growing with the popularity of solar energy. Use of solar, or photovoltaic, panels increased by 50 percent from 2003 to 2008, and forecasts suggest a growth rate of at least 25 percent annually into the future. Fostering the growth, he said, is emphasis on alternative energy sources and society-wide concerns about sustainability (using resources today in ways that do not jeopardize the ability of future generations to meet their needs).

Large-scale solar installations already exist in the United States, Spain, Germany, the Middle East, Australia, and India. These installations usually are located in sun-drenched desert areas where dry weather and winds sweep dust into the air and deposit it onto the surface of solar panel. Just like grime on a household window, that dust reduces the amount of light that can enter the business part of the solar panel, decreasing the amount of electricity produced. Clean water tends to be scarce in these areas, making it expensive to clean the solar panels.

“A dust layer of one-seventh of an ounce per square yard decreases solar power conversion by 40 percent,” Mazumder explains. “In Arizona, dust is deposited each month at about 4 times that amount. Deposition rates are even higher in the Middle East, Australia, and India.”

Working with NASA, Mazumder and colleagues initially developed the self-cleaning solar panel technology for use in lunar and Mars missions. “Mars of course is a dusty and dry environment,” Mazumder said, “and solar panels powering rovers and future manned and robotic missions must not succumb to dust deposition. But neither should the solar panels here on Earth.”

The self-cleaning technology involves deposition of a transparent, electrically sensitive material deposited on glass or a transparent plastic sheet covering the panels. Sensors monitor dust levels on the surface of the panel and energize the material when dust concentration reaches a critical level. The electric charge sends a dust-repelling wave cascading over the surface of the material, lifting away the dust and transporting it off of the screen’s edges.

Mazumder said that within two minutes, the process removes about 90 percent of the dust deposited on a solar panel and requires only a small amount of the electricity generated by the panel for cleaning operations.

The current market size for solar panels is about $24 billion, Mazumder said. “Less than 0.04 percent of global energy production is derived from solar panels, but if only four percent of the world’s deserts were dedicated to solar power harvesting, our energy needs could be completely met worldwide. This self-cleaning technology can play an important role.”

By Holly Prestidge | TIMES-DISPATCH STAFF WRITER
Published: August 28, 2010

Credit: EVA RUSSO/TIMES-DISPATCH

Solar panels on the roof of the garage are one feature of the energy-efficient home Randy Thomas and Diane Lewis are building in Chesterfield.

The running joke around Randy Thomas and Diane Lewis’ old Hanover County neighborhood was that the couple must have been from Vermont or Minnesota — anywhere cold.

That rationale would help explain why they installed solar panels, south-facing windows to catch the sunlight and warmth, and extra thick walls with added insulation in their home when it was built in the early 1990s.

If just a few environmentally friendly elements were enough to make people talk, just think what their new neighbors will say.

Thomas and Lewis, along with Mark Waring, vice president of Richmond-based Bain-Waring Builders, are building a home in Chesterfield County that’s so energy-efficient it’s among the first to be certified as such in Virginia.

Thomas and Lewis are building a zero-energy home, one that produces as much energy as its uses, therefore canceling out monthly heating and cooling bills. Through the use of solar panels, geothermal heating and cooling systems, a tightly sealed shell, energy-saving appliances — not to mention turning off lights when they leave a room — they’re looking forward to living in a home that’s not only cheaper for them, but better for the environment.

The timing, Thomas said, was just right for them to build.

“The technology has finally gotten to the point where you can reasonably do this kind of a home without a whole lot of extra work,” he said this month as he walked through what will soon be his new home. The house is approximately 2,900 square feet. From their front yard they can see the horses of nearby Keswick Farms.

“The materials are there, the technology is out there [and] the prices are coming down,” Thomas said, citing federal rebates and state grant money for solar panels and geothermal systems that cut their costs for those items by one-third.

On top of that, “if I don’t have to pay utility bills for the rest of my life, that really lightens the load,” he said.

Thomas and Lewis knew what they wanted, though finding information on zero-energy homes wasn’t easy. For that reason he started a blog so others could learn from their experiences.

“When I did Internet searches to try to get some guidance, there’s just nothing there,” he said. “I had to go through hundreds of entries before I’d find little nuggets that were actually helpful.”

They also needed a builder. Lewis and Waring knew each other from an eco-brokerage conference a few years earlier.

“We started talking about the kind of house we were looking to build, [and] I could see his eyes start to light up,” Thomas said. “The light bulb went on there. It really was a nice partnership.”

Every decision — from the type of paint to sorting through options for energy-efficient windows and appliances — was done within the larger scope of how it would affect the home’s efficiency, Thomas said.

Their new home is tightly sealed and well-insulated. It sits on a conditioned crawl space, meaning that the underbelly of the home is insulated exactly as the house itself, right down to the ground. There’s no insulation in the floor joists, and the air is blown into the crawl space so that it’s always the same temperature and humidity as inside the house.

Most homes built nowadays refresh air every one to two hours, but this home will do it every seven hours, Waring said. And while most homes leak air from ducts all over the house, at a national average of about 28 percent, this home’s ductwork is so tight that a fraction of that — about 2.5 percent — leaks out, he said.

Combine that with a geothermal heat pump, which uses the ground as its heating and cooling source, energy-efficient windows, ceiling fans and appliances, LED and compact fluorescent lighting, and solar panels on the garage roof, and you’ve got a home that doesn’t rely on carbon-based energy sources.

“Energy is going to be finite, whether it’s going to be in 20 years or 50,” Thomas said.

Before they move in, the house will undergo a series of tests to show how “green” it is and to check the energy efficiency of the home’s design.

EarthCraft Virginia is the organization that pressure-tests air systems, ductwork and more and then certifies homes at three levels, with the highest being the platinum level, which is what Thomas and Lewis are striving for.

High-performance homes, as EarthCraft Executive Director KC McGurren called Thomas and Lewis’ home, are “very rare, particularly with new construction.”

She said there are only two EarthCraft Platinum-certified homes in Virginia. While the average Earthcraft home is about 28 percent more efficient than traditional homes built today, McGurren said Thomas and Lewis’ home could be as high as 75 percent to 80 percent more efficient than a standard home.

Thomas said he’s been asked how long it’ll take for him to recoup the extra money he’s spent to make his home energy efficient. He said his energy-efficient options are no different from someone who turns a two-car garage into a three-car garage, or adds on a game room.

“Does anybody go back and say how many years before that extra garage pays off, or your pool-table room?” he said. “If it’s important to you, how is it any different?”

Waring echoed Thomas’ thoughts, using irrigation as the example.

“People always want to put that $5,000 in sod and irrigation,” he said. But they could put that extra money into their home “and all of a sudden it’s 40 percent more efficient.”

“And the grass dies every year,” Waring added.

Lewis said there’s a misconception that energy-efficient homes are much more expensive than standard homes. Waring said constructing a tight shell and duct system at this home has added about $3 to $5 per square foot. He said as homeowners add elements such as geothermal systems and solar panels, the costs can go up, though rebates and grants help with those expenses.

Thomas and Lewis are scheduled to move into their house next week.

“We’re getting of the age where you think about being creative . . . [and want] to pay something forward,” Thomas said. “This is an opportunity to try and do that.”

What’s going into this house

• Low VOC (volatile organic compound) paint means it has less of the toxic material that leads to poor air quality inside the home.
• Appliances — Energy Star appliances throughout the home.
• Tightly-sealed ductwork — Most homes leak air at a rate of about 28 percent. This home’s ducts will be sealed so that virtually no air leaks.
• Light bulbs — LED or compact fluorescent bulbs.

By Ucilia Wang

A survey published by the National Academy of Sciences earlier this week highlighted the fact that going solar isn’t high on the list of energy saving measures that consumers can take. In fact, more survey respondents said they would buy energy efficient lights, appliances and cars or “sleep more” if they had to choose a single most effective action they could take to conserve energy.

The researchers of the study concluded that cost is a big stumbling block to adopting energy efficient technologies because their subjects cited curtailing current energy consumption, like turning off the lights and hopping on public transit, as the top choices over buying new greener tech.

Which brings us to the topic of: just how expensive are solar electric systems these days and how to do you compare solar systems? I spoke with Molly Sterkel, program manager for the California Solar Initiative, to get some answers. California is the largest solar state in the country, thanks in part to the CSI incentive that gives rebates for installing smaller solar energy system owners (less than 30-kilowatts). Owners of systems 30-kilowatt or larger get payments on the electricity produced. Most homeowners install systems less than 10KW.

As it turns out, there is a lot of pricing information floating around that isn’t easily comparable. Over the past two years, solar panel manufacturers and their component suppliers have reported a steep drop in the costs of materials (up to 50 percent) along with the prices for which they sell their equipment. Back in May, Bloomberg Energy Finance’s Jenny Chase told me that major crystalline silicon solar panel makers were selling their goods at EUR 1.7 ($2.16) per watt and large solar power projects were being built at EU 2.7 ($3.43) per watt. In December 2008, the market research firm said the manufacturers were selling silicon-based panels at around $4 per watt.

But the lower costs and prices for manufacturers tend to translate into more savings for whole-sale purchases for large, megawatt-size projects. Consumers will pay more because they buy from retailers (installers), and the size of a typical system hovers from 3KW to 5KW.

Retail prices haven’t seen a dramatic fall. Check out this helpful retail price index by Solarbuzz for solar panels of all flavors in the U.S. and Europe. In the U.S., the retail prices have fallen almost 14 percent from $4.84 per watt in January 2009 to $4.17 per watt this month (excluding sales taxes), if you buy only one panel from a dealer.

A solar energy system is made up more than just solar panels; it comes with racks and other parts, and you have to consider the labor cost as well. Solar panels typically make up about 50 percent of the cost of installing a system. The homepage of Go Solar California, the umbrella term for the state’s solar programs, showed that the average price for a solar energy system at less than 10KW is $9.21 per watt. Sterkel pointed out that the number is an average of all the small systems installed over time, and it’s not adjusted for inflation.

So a better set of numbers would come from the CSI progress report posted in July this year, she said. Figure 9 of the report showed how much a buyer would pay for solar energy systems of less than 10KW, and the graph showed a gradual decline, from $10.04 per watt in the first quarter of 2007 to $8.49 per watt in the fourth quarter of 2009. That’s roughly a 15 percent drop. And it’s about an 8 percent cut from the beginning of 2008 to the end of 2009.

Sterkel pointed out that the financing options available to consumers, such as leases or power purchase agreements, have likely countered the effect of a big drop in solar panel prices. In a power-purchase agreement, homeowners pay for the solar electricity generated from the system on their rooftop, but the system is owned by their installer or an investor who financed the installation.

“It’s in our data that third-party systems cost more on average than” systems owned directly by consumers, Sterkel said. “People need to be aware that that’s what goes into a system’s cost, if financing is part of the system.”

One tricky thing about reading the CSI Progress Report chart is that the 10KW system size comes from a formula set by the California Energy Commission, and it’s in AC (alternating current). The same metric is used throughout the report. Solar panel manufacturers, on the other hand, typically discuss their prices in DC (direct current) because that’s the rating they use to describe the generation capacity of their panels. Solar panels are connected to one or more inverters in order to convert the DC to AC for feeding the grid, and the energy loss during the conversion means the AC number is lower. As a result, the cost-per-watt for a system rated in AC would be higher than in DC.

So, yes, it takes some math to get a better comparison of costs. But now you know where and what to look for. The price of a system depends mostly on its size, the brand of solar panels and other parts, as well as the local labor cost.  Sterkel said consumers should always get bids from three contractors in order to do a good price comparison. According to this CSI page, California consumers are likely see an average price of around $8.50 per watt. That means about $26,000 for a 4KW system, the average size of a residential system.

For more research on solar check out GigaOM Pro (subscription required):

Home Energy Management: Consumer Attitudes and Choices