Five Cool Facts About Solar that Kids Should Know

Editor's note: this blog was submitted by Nicky Palmer, 7th grader in Foster City, California.

Did you know that if we add up all of the solar energy that is taken in by the Earth’s atmosphere, land and oceans every year, we end up with about 3,850,000 exajoules? To put it in more understandable terms, this amount of energy is equal to 2.7 million earthquakes of the same size as the 2011 earthquake in Japan. That's a lot of energy we can use!

Another cool thing is that NASA has been working on a series of solar powered unmanned aircraft since the 1980’s. Pathfinder, Pathfinder Plus and Helios Prototype, is the result of NASA’s efforts to use solar power for long duration high altitude flights. The Helios Prototype reached a record altitude of 96,863 feet in late 2001, which is the highest altitude reached by an aircraft that is not powered by rockets for sustained horizontal flight.

The main benefit of solar energy is that it does not produce any pollutants and is one of the cleanest sources of energy. It requires low maintenance and is easy to install. Solar energy is a completely free source of energy and it is found in a lot of places. Though the sun is 90 million miles from the earth, it takes less than 10 minutes for light to travel from that much of distance.

The sun has produced energy for billions of years. It is the most important source of energy for life forms. It is a renewable source of energy unlike non-renewable sources such as fossil fuels. Solar energy technologies use the sun's energy to light and heat homes, and produce hot water and electricity.

The reason that solar energy is a renewable energy source is that the electromagnetic radiation emitted from the Sun (also known as sunlight) will be around for us to harness, and will not disappear anytime soon. According to scientists, the Sun was born about 4.57 billion years ago and has another 6-7 billion years before it becomes a white dwarf (a planetary stage where the star begins to die). Fortunately you don’t have to worry about this. When the hydrogen reserves on the Sun are gone, it will expand into a red giant, and will likely swallow the Earth. Luckily we have another 5 billion years before this will happen!

Elaine’s Climate Ride 2016

Hi, everyone! You might have seen my note in a previous NorCal Solar newsletter. This past May I bicycled in a charity bike ride – the California Coast Climate Ride. I raised over $5,000 for NorCal Solar, the American Solar Energy Society, and the Climate Ride organization. THANK YOU to everyone who donated so generously! That $5,000 is an impressive number! 

Here’s a quick report: the route was 320 miles (Fortuna to San Francisco). It’s a hilly route, starting inland at Fortuna then south along the Avenue of the Giants (redwood forest) then to the beautiful Pacific coast. My knees were not accustomed to that many uphills, and my bike had an issue on downhills, so I didn’t ride every single mile. But it was overall a great experience with 106 other spirited, enthusiastic, earth-friendly cyclists from many parts of the country. At the campgrounds in the evenings, we had guest speakers addressing various environmental topics, including Paul Hawken, a Bay Area writer and researcher whom you might recognize from his previous work on the Smith and Hawken gardening catalog. Climate Ride provided wonderful food, and a pair of massage therapists helped us loosen our tight cycling muscles each evening!

I’m delighted to say that I bought a small backpack with a flexible solar panel built into it right before the ride (see photo), and I used it to charge my cell phone several times. It worked great, both while I was riding and when I stopped at rest stops!

The Climate Ride group organizes a number of multi-day rides and hikes each year around the country to bring like-minded people together for mutual support, to raise money for nonprofits doing great work on clean transportation and energy and a host of other environmental areas, and to raise awareness about these issues. Think about it if you love to cycle or hike! Some of the 2017 events are already decided – visit Thanks again for your support!

-- Elaine Hebert of NorCal Solar

 At the end of one day, I got the photographer’s attention to help me show off my solar backpack. 

At the end of one day, I got the photographer’s attention to help me show off my solar backpack. 

 Here’s the entire group for our final photo in San Francisco! We’re wearing our matching Climate Ride cycling jerseys.  Photos by Kip Pierson, the official Climate Ride photographer

Here’s the entire group for our final photo in San Francisco! We’re wearing our matching Climate Ride cycling jerseys.

Photos by Kip Pierson, the official Climate Ride photographer

3 Reasons Why No One Will Show Up for California’s Community Solar Party

Community solar gives electric customers the opportunity to buy a portion of the output from an off-site solar facility. The beauty of community solar lies in how it encourages large, low-cost, solar projects to be sited where utilities need them most, while giving access to the environmental and financial benefits of solar power to those who cannot put solar panels on their roofs. In several states, renters can now subscribe to a community solar facility and save money on their electric bill because solar is cheaper than utility power. Community solar was pioneered by Sacramento Municipal Utility District’s Solar Shares program, and is now being expanded to PG&E, Southern California Edison, and San Diego Gas & Electric.

Last Thursday, after years of rulemaking in the wake of SB43, the California Public Utilities Commission approved the final rules for community solar programs at California’s three largest utilities. One would expect screams of joy followed by a gaggle of renewable energy developers lining up to submit project applications. Given the high cost of electricity in California, abundant sunshine, a robust solar industry, historically low cost of solar panels, a 600 MW program launch, and provisions that allow solar developers to contract directly with customers, this seems like a huge win. It’s community solar party time in California, right? Unfortunately, the program rules are so cumbersome, it’s doubtful that any solar developers will be able to build projects under the program.

Here are three reasons why guests aren’t RSVPing for California’s community solar party:

First: The customer bill credits are too low. In community solar, customers buy power from a solar developer and are credited by their utility on their monthly bill for the equivalent amount of power they are replacing. If the bill credit is greater than the cost of solar, the customer saves money. Unlike many successful community solar programs, the California rules only credit customers for the wholesale generation value of the power (which is about 1/3 of your electric bill) and then the utilities add in layers of program fees. For solar power developers to provide savings to residential PG&E customers, the developers would need to be able to build, market, and sell solar at below 6 cents/kWh. At Southern California Edison, the net bill credit for community solar is below 5 cents/kWh. By comparison, residential community solar bill credits in Minnesota are 14.74 cents/kWh, and are even higher in Massachusetts; those are two of the largest markets for community solar. Meanwhile, for community solar projects, PG&E is charging 1.37 cents/kWh for program fees and another 2.3 cents/kWh for Power Charge Indifference Adjustment (a “departing load” charge).

Second: The complexity of the bill credit system for the program destroys the value proposition for the customer. The program involves numerous floating charges to be adjusted annually by the utility, which removes the stable-price financial benefits that solar provides. It makes it extremely difficult for developers to explain the program benefits to potential customers. Customers installing solar on their homes can lock into fixed, affordable rates for the long term without being subject to the same fees. The price stability benefit of solar simply isn’t possible to convey to customers under the overly complex community solar program rules in California.

Third: The program is overly burdensome for solar developers and creates a level of risk that will keep them out of the market. The program includes two primary areas of risk for solar developers: unsubscribed power and off-take requirements. For solar projects that are not fully subscribed by customers, the unsubscribed power from the facility would receive a wholesale payment from the utility that is so low that the project could not be financed. Investors who pay for project development may not want to take on the risk of customers cancelling or not enrolling. To make matters worse, the program rules require that solar developers enroll “At least 50% (by number of customers) and at least 1/6th (by load)” from residential customers. For developers, that’s bad news. The bill credits for residential customers are lower than for non-residential customers, so by creating a residential carve-out, it makes already bad project economics worse for developers. Requiring a specific amount of residential customer participation may result in a program that is completely unworkable for all customer classes.

In sum, the program will not have a sufficiently meaningful value proposition to attract customers, and it will be difficult or impossible for solar developers to make projects pencil out. Therefore, developers will likely not be willing to take on the risk of building projects.

So what’s next for community solar in California? Developers have the opportunity to identify potential projects, market those projects to prospective off-takers, and apply into the program supply auction at the end of the summer. Time will tell whether there are any takers.

They sent the invitations out for a community solar party here in California, but I doubt that anyone will show up.

Support Elaine's Climate Ride for NorCal Solar and ASES!

Hi Everyone - I'm Elaine Hebert, and I've been active with NorCal Solar for 20 years. I really believe in protecting a beautiful, livable environment. I've decided to undertake a huge physical and social challenge in my 61st year of life on planet Earth. Have you heard of Climate Ride? I'm going to ride my bicycle 320 miles in 5 days to raise money for NorCal Solar and our "parent" organization, the American Solar Energy Society. I'll be in the California Climate Ride May 22-26. Could you support me with a donation? Climate Ride requires that each rider raise $2800, but I'd like to raise more. I'm about halfway to the Climate Ride goal as I write this. You can donate online with a credit card or download a form and mail it with a check directly to Climate Ride. Follow this link for details. Thank you! Feel free to contact me at

If you'd like to ride in a Climate Ride or hike in one of their hikes yourself, these events are scattered around the country and throughout the year. Visit for more info. It's a great way to meet great people involved in climate-related nonprofit work and support a lot of good causes!



Microinverters, String Inverters & Optimizers

(Originally posted on Heatspring, NorCal Solar board member Sean White discusses the latest in inverter technology. 

Student 1: I am enjoying the course and I like the way you explain things by citing real world examples. I just want to get your opinion on microinverters. These provide great solutions for power optimization and rapid shutdown, not to mention the flexibility of combining and running the wires.

My concern, however, is how well they can withstand adverse weather conditions on the roof compared to better conditions where the string inverters are usually located? My other concern is the microinverter maintenance and replacement– someone has to climb on the roof to find and replace it.

Thank you!

Sean White: Hi Student 1. The benefits of microinverters are obvious, and if you talked to microinverter people, you might wonder why anyone would install anything else. I will give you the string inverter position that many string inverter people get emotional about.

This is what SMA says:

The Enphase microinverter came out in 2008 (8 years ago), they have a 25 year warranty, but nobody knows what will happen in 25 years. Electronics tend to go by what they call the “bathtub curve”… or, failure at the beginning of the lifespan or at the end. Typically, the middle is safe.

If you have 30 modules on a roof and you install 30 microinverters and each microinverter lasts an average of 30 years, then you could have 30 instances in which you have to deal with broken inverters over 30 years. If you have 30 modules and a single string inverter and if the string inverter lasted 15 years on average, then you would have to replace inverters 1 or 2 times. String inverters are significantly less expensive, so you could buy a few extra modules to make up for the decrease in performance.

String inverters are not subject to the christmas light effect. If you have a string and a module or 2 or 3 is shaded, then the bypass diodes will kick in and bypass the shaded section of the module. The modules are divided in thirds, so a shadow can take as little as 1/3 of a modules performance off of the string.

With a microinverter, instead of the bypass diode kicking in, the module can work as if it were in the shade, which is a better than being totally bypassed. A module in the shade may produce 10% of production, so it is not a lot to worry about. Most string inverters now have 2 channel MPPT, so shading with one string or different string lengths is not a problem. Also SMA has a Secure Power Supply, which is really cool.

Now, let’s look at why optimizers are often said to be the best… as a Solar Edge representative might say:

Optimizers only have the DC under the module and those microinverters will break because the AC components can’t handle the rooftop and the test of time. Optimizers let you maximize your “string” length, because the electronics can control the voltage and current, unlike a normal PV source circuit.

Another thing that optimizers can do is feed the inverter the exact voltage which will make it work most efficiently.

690.12 Rapid Shutdown will be enforced in most places where solar is installed in 2017, so there is still 11 months where many systems will be installed without rapid shutdown (half of the solar in the United States is installed in California, and many other states also are on a similar code cycle).

An argument against optimizers: you have to install equipment under the PV and a regular inverter.

All being said, microinverters are easy to install by any electrician, they are safe, the monitoring is cool and the production is great. I install all of the options and try not to take sides. I hope I appeared neutral here.

Great news from Congress – the ITC is extended!

by Eric Larson, President, NorCal Solar

The year-end omnibus bill recently passed by Congress includes an extension of the Investment Tax Credit for residential solar.  This was a welcome surprise for all of us working to grow solar and renewable energy use!  The  Federal tax credit was due to expire at the end of 2016.  With this bill, it has been extended for an additional 3 years at 30%, then ramps down to 10% for 2022 and beyond.  

We at NorCal Solar are very excited about this commitment by the US government to support the continued growth of solar installations in the US.  

While there are still challenges in policy and public awareness, NorCal Solar is very encouraged by this action.  Greentech Media has a great article with more details at:

Slides from NorCal Solar 2015 Speaker Series

On June 18, we held Part 2 of our Speaker Series: PV Systems and Grid Integration featuring talks by Chase Sun and Terry Surles.

Our speakers were generous enough to provide their slides for download.


Solar Permitting Fees Update

You may have read – or experienced yourself – that the fees charged by cities and counties for solar installation permits vary tremendously across the state – even in cities right next to each other. Some of those fees are exorbitant compared to the average. Kurt Newick, a NorCal Solar member and an activist, couldn’t take it anymore.

Several years ago, Kurt worked with his local chapter of the Sierra Club (Loma Prieta chapter) to begin contacting jurisdictions across California county by county to find out their permitting fees, to be able to compare them and understand the depth of the problem. We published some of his results in the 8th edition of this Resource Guide, and Kurt and his team keep updated information on their website.

Kurt reports that he’s been traveling to Sacramento to help advise on legislation to address the permit fee problem. Scroll down on to track the latest on legislation, but as of this writing, three bills are pending:

  • SB 1222 (Leno): Specifies limits on PV permit fees and prohibits cities and counties from charging more than a reasonable amount.
  • AB 1801 (Campos): “Requires solar permit fees to be computed based on actual jurisdictional costs and specifically prohibits fees from being computed based on PV system valuations. This will impact solar permit fees for all sizes and types of solar energy systems.”
  • AB 2135 (Blumenfield): “Creates guidelines and standards for solar permit processing.”

(Citations are from from Loma Prieta Chapter of the Sierra Club.)

Kurt and his team have worked hard to bring reason and consistency to this problem. Many jurisdictions have adjusted their fees and streamlined the permitting process.

Kurt can be reached at by phone (408-370-9636) or email. The Sierra Club’s studies of permit fees are on their website.

Net-Zero Energy, Soup to Nuts

Ann V. Edminster, M.Arch, LEED AP

Author of Energy Free: Homes for a Small Planet

Ready or not, by executive order, California homes have been mandated to achieve net-zero energy: new homes by 2020, existing homes by 2030. In the simplest terms, this means that a home will have to produce at least as much clean, renewable energy each year as the occupants of the home use in that year. While definition details and implementation specifics have yet to be worked out, California’s Public Utilities Commission and Energy Commission are working furiously to put the infrastructure in place to achieve this extremely ambitious goal.

Net-zero energy is also taking hold nationally and internationally, with help from the US DOE’s Builders Challenge, the US-Canada Net-Zero Energy Home Coalition, the international Passive House movement (along with its domestic adherents), and other initiatives in Europe and beyond.

Completed net-zero energy home projects exist across the housing spectrum, rawww.netzeroenergyhome.canging from single-family custom homes to production subdivisions to affordable multifamily developments. Each type poses a different degree of challenge, but there are some common denominators. For starters, achieving net-zero energy is going to require a fairly strict adherence to the “loading order” – i.e., incorporating energy features in a sequence that is based on getting the greatest energy performance gains at the lowest costs.

The rest of this article offers a few high-level points about each of the steps in the loading order, which should be prioritized in the order shown.  Optimize the basic building geometry and orientation. The enemies of net-zero energy (and durability and comfort, incidentally) include poor orientation and overly complex building geometry. Translated, this means:

  1. Do your best to orient the house with the long axis east-west;
  2. Keep most of the glazing on the south side;
  3. Maximize your south- and west-facing roof space;
  4. Keep the basic form as close to a shoebox (basic rectangle) as you can;
  5. Think elegant and simple, not fussy and convoluted.

Create a thermally robust building enclosure (appropriate to the climate).

A good thermal enclosure comprises four principal elements:

  1. Above-code insulation (greater R-values than Title 24 requires for your climate zone).
  2. A high quality insulation installation. While this may be hard to believe, most insulation is installed with insufficient attention to detail. Batt insulation, in particular, should be installed so that it is in full contact with all six faces of every framing cavity, with only very small voids and areas of compression. This is absolutely not the norm. Take care to seek out insulation contractors who are energy-efficiency advocates and enthusiasts.
  3. Superior air sealing, to prevent heated and cooled air from leaking through the building enclosure – you paid to heat or cool it, don’t waste that investment!
  4. High quality windows. Windows should have a below-code U-factor (thermal conductance), optimized solar heat gain coefficients (SHGC), and solid construction for longevity. Compression-type operation is also a plus, because it minimizes air leakage – casements, awnings, and hoppers.


Minimize heating and cooling needs with passive design strategies.

Passive design strategies are particularly important in hot climates, where air-conditioning can rack up electricity use. Include overhangs and other shading devices that are “tuned” to the direction the windows face and how much direct sun they receive during the hottest times of year. Passive ventilation strategies, such as “thermal chimneys” and windows carefully placed high and low on opposite walls, can also be effective features to help minimize reliance on mechanical cooling.

Passive solar heating can also be helpful, but should be designed with caution to avoid overheating in super-insulated homes. Keep mechanical and water system layouts as simple and centralized as possible. Although a lot of emphasis is placed on efficient mechanical equipment –- and I don’t deny it’s important –- the overall design of the mechanical systems is generally overlooked. Among numerous aspects that should be factored into an efficient design are:

  1. Minimizing the length of duct runs (and hot water piping).
  2. Minimizing duct leakage.
  3. Keeping ducts in conditioned (heated/cooled) parts of the building.
  4. Ensuring all parts of the system are correctly installed and tuned.

Choose efficient mechanical and water heating equipment, lighting, and appliances.

Each different type of equipment has a different efficiency metric, and there are acronyms galore. Here are just a few:

  • Energy factor (EF), for water heaters;
  • Annualized fuel utilization efficiency (AFUE), for furnaces;
  • Coefficient of Performance (COP), for heat pumps;
  • Water factor (WF), for clothes washers.

The American Council for an Energy Efficient Economy ( offers a comprehensive guide to efficient household equipment and appliances. Three other excellent resources for selecting highly efficient household items are:

  • The Consortium for Energy Efficiency (, which lists appliances in order by efficiency;
  •, which lists the ten most efficient models of a wide range of different devices, from televisions to refrigerators;
  •, which provides additional product listings as well as well-researched and informative product selection guidance.

Incorporate strategies that help occupants control electrical use from plug-in devices.

So-called “plug loads” are an increasingly dominant part of the energy use picture for virtually all American households. The two big categories are entertainment devices and home office electronics. Thoughtful designers can help occupants control the energy use from these devices by understanding how they are used in our everyday lives, and accommodating controls for those uses conveniently. For example, locating plugs and switches for entertainment centers and desks where they are readily accessible can encourage energy conservation behaviors.

Design renewable energy systems to complement your highly energy-efficient dwelling.

Renewable energy systems –- the supply side of the net-zero energy equation -– are typically the most expensive ingredient of a net-zero energy home. Most homes also have limited real estate to devote to them. These factors dictate that we make the most out of our efficiency opportunities before we turn to renewable energy to help us get to net zero. We absolutely can’t achieve net-zero without these systems, but we need to maximize all the other tools in our toolkit, too.