It’s the storm of the century out there. How does that impact my solar production?

It’s been a busy winter for weathermen. First, Stormageddon drenched northern California in rain. Then, Snowpocalypse buried the Northeast in snow up to two feet deep. Now, frequent storms in the Boston area have crowned the winter of 2014-2015 as one of the top 10 snowiest in the city’s recorded history.

For some, wintry weather means school cancellations, flight delays and maybe even urban skiing. For solar homeowners, it may also cause worry that their solar system isn’t producing as expected. How and by how much did Stormageddon and Snowpocalypse, representing one rainy and one snowy weather event, impact solar production? That’s the question we set out to answer using actual production data collected from hundreds of Sungevity customers. (But first, a word from our lawyers: the following data has been anonymized and presented in aggregate to protect the privacy of our customers.)

We hypothesized that the data would follow these proven trends:

Now, let’s see what happened in these two examples.

Stormageddon: I Don’t Want To Miss A Rain

Stormageddon pelted California’s Bay Area with rain and high winds, with some areas seeing over 8 inches of rain. Let’s take a look at how Sungevity system production was impacted during the storm, as compared to the previous week.

Not surprisingly, 70% of Sungevity customers saw a decrease in their system production. However, the change was fairly modest: the average system produced 80% the electricity it had produced the week prior. More surprisingly, for those remaining 30% of customers who didn’t see a decrease in production, the week of the storm was actually a positive one: 157% increases, on average.

Table 1: Sungevity’s Bay Area System Performance During Stormageddon

Did System Production Increase or Decrease? Percentage of Sungevity Systems Average Change in System Production
Increased 30% 157%
Decreased 70% 80%

Why would rain increase solar production? Perhaps the rain cleaned the panels of dust that had built up during the long dry spell that northern California experienced before the storm. (We’ll look at best practices for cleaning your solar panels in a future blog post, so stay tuned.) Or perhaps the sun got jealous that the storm was trending on Twitter and decided to shine harder.

Snowpocalypse Now

Next, we examined solar production before and after Snowpocalypse to evaluate the impact that heavy snowfall has on our customer’s solar production. We compared Sungevity production data from four metro areas – Albany, Boston, Hartford, and Long Island – that were hit by the snowstorm and analyzed how precipitation levels impacted the amount of electricity each system generated.

The results are clear: solar production dropped significantly on the days that snow fell. At the storm’s peak on January 26th and 27th, aggregate production dropped to nearly zero in every area.

Figure 1-4: Sungevity System Performance in the Northeast During Snowpocalypse

Albany Metro Area_final w snowflakeBoston Metro Area_final with snowflake   Hartford Metro Area_final with snowflakeLong Island NY_final with snowflake

Production also took a few days to bounce back after the storm, which presumably represents the time it took for the snow to melt and uncover the panels beneath. Production on Long Island, for example, returns to normal on January 31st, four days after the storm. But note that, in every case, production did bounce back: the data shows that many systems began producing electricity as soon as precipitation returned to zero.

The Bottom Line

It’s true: inclement weather will impact your system’s production. Snow has the most significant effect of all because it can create a physical barrier between sunlight and the solar panels. But in the end, when the clouds clear and the snow begins to melt, homeowners can expect their solar production to return to normal levels for the season.

But Don’t Worry, We’ve Got You Covered

This data demonstrates exactly why it’s important that solar companies have a robust methodology to take seasonal variation into consideration for predicting annual solar production. Almost all companies account for seasonal differences in temperature and solar radiation. Sungevity also incorporates an analysis of historical snowfall to provide an accurate prediction for our customers. And, we provide a Performance Guarantee so that our customers can have complete peace of mind, no matter the weather.

If you have already switched to solar, just remember: the low production that you experience this winter will be balanced out by the high production you will see in summer, when precipitation is at its lowest and the sun is higher in the sky. So, here’s to a sunny spring and summer!

The biggest match-up of Super Bowl weekend is not what you think

It’s not football. It’s not even puppies. It is the…

the Solar Bowl

Sunday’s game between the Seattle Seahawks and the New England Patriots is predicted to be a near toss-up. What is guaranteed to win is renewable energy, regardless of the score. The Salt River Project, a local utility, has pledged to purchase enough renewable energy credits to cover 100% of the electricity consumed at Glendale Stadium during the game. Arizona Public Service Company, another utility, will purchase renewable energy credits to offset electricity usage at Super Bowl-affiliated venues in downtown Phoenix, such as the hotels where the teams are staying.

This begs the question: how “renewable” are these teams the other 364 days of the year? We collected solar statistics for each team and their hometowns* to see how they stacked up.

Seattle Washington solar statistics        SolarBowl Trading Cards_Boston v1

(*We used Boston for comparison’s sake, though the Patriots play for all of New England.)

When it comes to population size, the two cities are roughly identical. But when it comes to solar, it’s not much of a contest. Not only does Boston have more total solar capacity installed (12 MW versus 4 MW), but even the stadium where the Patriots’ play generates more solar electricity: 1 MW compared to 0.8 MW on the Seahawks’ CenturyLink Field.

It’s no surprise that Boston has embraced solar to a greater degree than Seattle given that Boston has more overall solar potential, as measured by the amount of sunlight available for PV generation. On top of that, Boston is number 2 in the United States for having the best conditions for maximizing the return on your solar investment, second only to New York, NY. Seattle comes in at number 42.

It’s your move, Seattle. Can you make your solar game as legendary as your defense? Tune in next year to find out.

Your Solar System This Winter

picture of Sungevity home solar system in the snow

A Sungevity solar installation in Highland, NY sees snow for the first time.

The snow storm dubbed #snowpocalypse that hit the East Coast on Monday may not have lived up to its hashtag, but even a little snow can make life more complicated. On the bright side, your solar system doesn’t require any additional maintenance to run smoothly in snowy weather. Just keep these simple tips in mind to keep your system operating safely all winter long.

Be aware of snow and ice accumulating on your solar panels

After heavy snowfall, snow or ice may accumulate on your rooftop and cover the panels. Please do not try and remove the snow yourself – we don’t want you to slip and fall. The snow will slide off on its own as the sun warms up the panels, and the system will go back to producing electricity. Please use caution and good judgment when walking under or around the panels while there is snow on your rooftop. Try to avoid parking your car, or keeping other valuables, under the roof’s edge.

Don’t worry that your system is producing less electricity these months

You may see your system’s production decrease these winter months, and that’s normal! We took seasonal variation into consideration when we designed your system and estimated your annual production. You have the upcoming summer production to look forward to and Sungevity’s production guarantee on your side.

Consider these energy saving tips to make the most of your clean electricity

Using energy more efficiently this winter can also help keep your utility bills under control. Before turning on your heater, check your ducts for leaks. Make sure to close your damper when the fireplace is not in use. And our favorite: take advantage of sunny days to heat your house. Open the curtains on your south-facing windows during the day and close them at night to lock the warmth in.

No matter the forecast, remember that we have your back

Don’t hesitate to email us at if you have any questions or concerns.

Would you spend $11.65 on a cup of coffee?

Let’s be honest: no. You’d take matters into your own hands and finally start brewing your coffee at home, like you’d always intended to.

pge-blog-coffeeThe good news is that coffee doesn’t cost $11.65 today, nor will it 20 years from now. But it might if coffee prices were increasing at the same rate as your electricity bill.

Say that the average price of coffee from national coffee chains is $4.00 today. If prices continue to go up at the same rate they have over the previous 20 years  (2.09% per year, approximately the same rate as inflation), that same cup of coffee will cost about $6.05 in 2035.

Imagine now that the price of your coffee increased at the same rate as your electricity bill. Take Maryland, for example, where the price of electricity has increased at an average rate of 5.49% per year over the previous 10 years.* At that rate, a $4 cup of coffee would cost $11.65 in 2035.pge-blog-chart

What does that add up to? For a daily coffee drinker, that amounts to spending $17,103.45 more in the next 20 years, an increase of nearly $1,000 per year.

So when PG&E recently announced a rate increase that added $5.23 to the average homeowner’s monthly bill, or when National Grid issued winter utility bills that were 37% higher than last year’s, why didn’t their customers switch to another electricity provider?


That’s because many Americans don’t have a choice – their utility is the only electricity provider in their region.

Or, we should say, didn’t have a choice – until now. Home solar energy now offers many homeowners a predictable and sometimes cheaper way to generate electricity. It’s like being able to lock in the price of coffee at $4 for the next twenty years and using the thousands you save for a few vacations to Hawaii.

Don’t take our word for it. Research your options. The beauty of solar is that you now have the freedom to choose.pge-blog-sun

Click here to see the states Sungevity currently serves. Visit the U.S. Energy Information Administration (EIA) website to learn more about electricity rates in your state. Have other questions? Let us know in the comments below.

* Data taken from the EIA’s Electric Power Monthly, “Average Retail Price of Electricity to Ultimate Customers”, in December 2004 and September 2014. The rate of electricity varies by state and utility. Visit the EIA website for more information.

5 Solar-Powered Gifts Under $100 Your Family Will Love


Are you looking for the perfect sustainable gifts this holiday season? Look no further.

1. Frightened Grasshopper ($11.95)

You may recognize this fun stocking stuffer from one of our Solarbration events. Put this wide-eyed little grasshopper in the sun and watch the kids go wild. Some assembly required.

2. WakaWaka Light + Charger ($79.99)

Designed from 100% recycled materials, this portable solar charger can power up your small devices within hours or provide up to 150 hours of bright light. And you can trust that this rugged device will last – WakaWaka also donates one per purchase to families in disaster zones to provide electricity and light where they are needed most.

3. Rydon Pixio Bicycle Lights ($43.47)

These theft-proof, waterproof bicycle lights are durable enough for whatever life has to throw at them. Their efficient solar panels keep your lights shining bright all winter long, so you don’t have to worry about replacing batteries in any season.

4. Goal Zero Rock Out Rechargeable Speaker + Nomad Solar Panel ($89.99)

Music for families on the go. These colorful speakers provide music for 20+ hours on 2 hours of charge. Great for summer picnics and hard-to-reach areas of your backyard.

5. GoSun Mini Solar Stove ($55.00)

Bye bye, barbeque. Hello, sunshine. The parabolic design focuses the sun’s rays on the cooker inside, and can heat your food up to 400˚ F in 5-10 minutes. The perfect size for hot dogs, cashews, garlic, and whatever else you can cook up.