The Energy Show: Cleaning Solar Panels

The Energy Show: By Barry Cinnamon

When a business or homeowner gets a new rooftop solar installation, the second question they always ask is “how often do I need to clean my solar panels.” We’ll answer that question on this week’s show — taking into account the different effects of rain, dust and electric rates. BTW, the first question people always ask is “how do I read my electric bill;” but that’s a topic for another show.

Rooftop solar panels get dirty primarily from wind-blown dust and pollen. Birds are usually not a problem unless your last name is Hitchcock and you live in Bodega Bay. As panels get dirtier, their output declines. A small amount of soiling — say a light dusty film — may only cause a 5 percent output decline. However, when panels get very dirty — perhaps in an agricultural area or location that does not get regular rainfall — the output decline can be greater than 20 percent. A good heavy rainstorm will usually wash away most of the accumulated soiling.

I use the term “usually” because on panels that are tilted at about 5 degrees or less, the rain may leave a puddle of muddy debris along the lower edge of the panel. When this puddle dries, sometimes a thick layer of dirt accumulates along the lower row of cells (sometimes moss and weeds may even grow in these areas). Depending on the design of the system, this small accumulation of dirt can cause a very significant decrease in output.

So the answer to the question: “how often should I clean my solar panels” really depends on five factors: your location (does it rain regularly or only during certain months), the tilt angle of your panels (steeply tilted panels tend to stay much cleaner than panels that are close to horizontal), the amount of wind blown dust, your electric rate (if your electric rate is high then it is more worthwhile to clean your panels), and the cost to clean your panels.

If you have a large solar array at a low tilt angle in a dry climate with high electricity costs, our basic advice is to clean your panels once a year. Under these circumstances the additional electricity output from clean panels will be much greater than the cleaning costs. On the other hand, if you have a small array in an area that rains regularly, then it may only make sense to clean your panels every five years or so. Here in California it generally does not make a lot of sense to clean your panels in the late fall or winter during the rainy season.

Regardless of your circumstances, please make sure you clean your panels with soapy or treated water to prevent damage from mineral deposits. Contact your solar contractor or maintenance company if you would like your system cleaned professionally. For more about keeping your solar system operating at top efficiency, please Listen Up to this week’s edition of the Energy Show.

Bronx Community Solar Farm Starts Taking Subscriptions

By Frank Andorka, Senior Correspondent

New York’s Governor Andrew Cuomo has set lofty solar goals for his state as it tries to catch up to its Northeastern neighbors like Massachusetts and New Jersey. And in the Bronx, one organization is trying to help him meet them.

CleanChoice Energy, a renewable energy company that provides wind and solar energy products to customers across the country, has opened subscriber enrollment for the Altus Bronx Community Solar Farm. The new Community Solar Farm is located on a commercial building in the Parkchester neighborhood in the Bronx. With space available to more than 150 residents, it is one of the largest Community Solar enrollments ever opened in the Bronx. Residents across the Bronx, and all of New York City, can support local solar and save up to 5% off their utility bills by becoming subscribers to the Altus Community Solar Farm.

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“Bringing Community Solar to the Bronx is hugely important. The Altus Bronx Community Solar Farm means that more people than ever can access clean solar energy while saving money on their utility bills,” said Tom Matzzie, CEO of CleanChoice Energy. “Community Solar allows New Yorkers to support local solar without a big upfront investment or a home construction project—instead they can sign up online in just a few minutes and save money on their utility bills.”

Altus Bronx Community Solar subscribers can live in any part of New York City and will receive credit on their electric bill for the power generated by the solar panels at the site. CleanChoice’s platform connects people to local community solar projects, allowing customers to sign-up in less than five minutes, and manages ongoing customer engagement–all fully digital and completely online. CleanChoice Energy Community Solar subscribers pay no upfront costs, have no maintenance, and do not need to own their roof—allowing anyone to support local solar even if they rent or do not have a roof suitable for solar panels.

Virginia Sets Aggressive New Solar, Wind Goals

By Frank Andorka, Senior Correspondent

Virginia is a solar state you on which you sleep at your own peril. It has long caught the eye of trend-spotters who believe it is on the verge of being the next solar boom state but, for various reasons (mostly political), it has never quite lived up to its solar potential.

This week, however, Governor Ralph Northam took steps to change the future, unveiling a plan to build nearly 5 GW of solar and wind resources. The plan sets aside 2 GW for offshore wind and sets the other 3 GW aside for solar and onshore wind. It’s not entirely clear from the plan what percentage of that 3 GW will in fact be solar.

The timeline for this development is 10 years.

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“The clean energy sector has the power to create new business opportunities, expand customer access to renewable energy, and spark the high-demand jobs of the 21st century,” said Governor Northam. “Virginia can shift to a more modern electric grid that is reliable, affordable, resilient, and environmentally responsible—and the Commonwealth can lead this critical industry as a result. This plan sets an ambitious path forward for Virginia, and I am confident we will charge ahead towards progress over the course of my administration.”

The plan builds upon implementation of the Grid Transformation and Security Act (Senate Bill 966), which Governor Northam signed into law earlier this year.

A solar revolution in Virginia has been on the horizon, coming in fits and starts as corporations like Facebook settle into the state and are starting to demand solar as part of their electricity generation. Former Governor Terry McAuliffe set the stage, signing a flurry of pro-solar bills before leaving office and launching significant state investments in solar at the state’s universities. But utilities like Dominion Energy have fought behind the scenes to slow rooftop solar development even as they invest in utility-scale solar themselves.

It should be noted that the new plan does not specify whether the development will be utility-scale or rooftop, either – so it bears watching to see how the solar revolution unfolds in Old Dominion.

Wind, Solar Join Forces In New Wind Solar Alliance

By Frank Andorka, Senior Correspondent

As wind and solar continue to grow as a percentage of U.S. electricity production, it makes sense for new groups to form to bring to bear the combined power of the industries in the political fights to come. That’s why it’s so exciting to see the formation of the Wind Solar Alliance (formerly the Wind Energy Foundation) to bring together the heavy hitters from both industries to work on mutually beneficial policy fights.

Having led national wind-solar advocacy campaigns for several years through its “A Renewable America” program, WSA saw an opportunity for increased collaboration between the two sectors, compelling the re-brand.

“There are many areas where the wind and solar agendas align,” said Abigail Ross Hopper, President and CEO of the Solar Energy Industries Association (SEIA). “We’ve seen great benefits from working with the wind advocates on federal, regional, and state policies on the “A Renewable America” campaign, and in other areas, over the past several years. We hope to continue to expand these meaningful efforts going forward, with support from the philanthropic community.”

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“Accelerating the deployment of wind and solar technologies is one of the fastest ways to mitigate climate change while strengthening the U.S. economy,” said John Kostyack, executive director of the Wind Solar Alliance. “The new name reflects our view that wind and solar industry leaders and other energy experts are stronger working together on this shared agenda than apart. Our coalition effort is now well-positioned to reform the U.S. electricity markets, as well as transmission and utility procurement planning processes, and thereby to rapidly scale these two technologies.”

Dan Shugar, NEXTracker founder and CEO, and Colin Meehan, First Solar’s Director of Regulatory and Public Affairs, join leaders from other solar-only, wind-solar, and wind-only companies on the WSA board. The American Wind Energy Association’s (AWEA) CEO, Tom Kiernan, also sits on the WSA board. Mark Alhstrom, President of the Energy Systems Integration Group and one of the nation’s leading experts on integrating renewable energy onto the electricity grid, serves as a board advisor.

The Wind Solar Alliance will continue to focus on research, communication, and advocacy to raise awareness of the benefits of renewable energy. In addition, the organization will give increased attention to addressing the need for policy changes in the Independent System Operators, Public Utility Commissions, and other venues that determine whether renewables will be given a fair opportunity to compete in the electricity marketplace.

WSA’s education and advocacy campaigns (the Grid Campaign, the Renewable Energy Jobs Tour, and Electric Nation: Powered by Wind) are supported with funds from major foundations, AWEA and SEIA, and leading wind and solar companies. The campaigns mobilize leaders from the wind and solar industries and other experts to deliver facts, data, and personalized messages to decision makers about how renewable energy is helping to improve our economy and environment.