Solarize is a group purchase program designed to simplify and reduce the cost of investing in solar energy. The campaign organizes a volunteer committee of residents to competitively select a solar installer who agrees to set pricing. At a series of free educational workshops participants can learn about the technology, incentives, and financing options. Interested, participants can then sign up for a free site assessment and are guaranteed the Solarize price, if they sign a contract within the campaign timeline. Customers can save as much as 25% of the total cost of installation. This approach enables grassroot and other solar advocates to build motivation and engagement over time, reduce key barriers to action, convert “interest” into “action”, and permanently transform the market for solar installations in their communities. Resulting installations generated 62,000,000 kWh of clean energy supply each year. Designated a Landmark case study by our Building Energy peer review panel in 2021.
Note: To minimize site maintenance costs, all case studies on this site are written in the past tense, even if they are ongoing as is the case with this particular program.
Solarize began in Portland in 2009, when one person who wanted to install solar power organized neighbors to “go solar”, make an informed purchase and get a volume discount together. They turned to their local neighborhood coalition, Southeast Uplift, for assistance. Southeast Uplift approached Energy Trust of Oregon for technical and program planning support. By coincidence, Energy Trust had developed a solar PV volume purchasing program and was eager to test the model. Within six months of starting their campaign, solar electric photovoltaic (PV) systems were installed at 120 homes, adding 350 kW of new capacity and saving roughly 360,000 kWh of conventional electricity per year.
Additional Solarize campaigns were initiated and replicated by Portland’s Neighborhood Coalition network with help from the Energy Trust of Oregon, the City of Portland’s Bureau of Planning and Sustainability, and Solar Oregon. Over two years and multiple campaigns, over 600 PV systems were installed. By the end of year three, Portland had added 1.7 MW of additional solar generation.
While there was no set process for how a Solarize campaign is created or organized, the National Renewable Energy Laboratory and the City of Portland developed a Solarize Guidebook in February 2011 for communities wanting to replicate the model. This helped spread the approach throughout Oregon to include over 25 Solarize projects and over 4 MW of newly installed solar energy. The following year, an updated Guidebook was funded by the US Department of Energy.
While the first campaign appears to have been conducted with little prior audience research, this was corrected over the following years. Each successive project contributed additional information. For example, researchers from Yale University performed multiple waves of randomized field trials specifically tailored for Solarize programs in conjunction with the 2013 and 2014 Solarize Connecticut programs. The SEEDS II team found that messages that focused on individual benefits like energy cost savings were up to 50% more effective than messages that focused on community benefits and social norms.
In 2017, a team from Portland State University and the National Renewable Energy Laboratory examined residential PV adoption and non-adoption, the varieties of adopters and non-adopters, and the roles of policies and marketing in shaping these segments. The survey data were collected from nearly 3,600 single-family, owner-occupied households across four different states: Arizona, California, New Jersey, and New York.
Solarize programs have been offered in various forms over time, but they all include the following defining elements of this approach. (Financial Incentives; Norm Appeals; Overcoming Specific Barriers; Word-of-Mouth)
1. Competitive Contractor Pre-selection
2. Limited Time Offer
3. Reduced Price through Bulk Purchasing
4. The Involvement of a Local Community Group


Photo images supplied by Spark Northwest
In 2015, Mother Earth News summarized the pros and cons of the Solarize approach as follows.
Pros
Cons
Mother Earth suggested that the Solarize approach had been particularly helpful in the early days of solar when there were fewer trained contactors and tools. It advised that now, “Online solar marketplaces offer much more choice and transparency to solar shoppers, and $0-down solar leases can provide an alternative for cash-strapped homeowners."
However, others noted that it had mostly been affluent white people who had first benefitted from Solarize programs, and that the approach was still relevant to less affluent communities and communities of color. According to RMI, while Black and Hispanic Americans were more likely to be concerned or alarmed about climate change than White Americans, they had installed significantly fewer solar systems. “Communities of color have been shown to have a 24–27 percent higher energy burden than White Americans when controlling across income levels, and low-income residents experience an energy burden up to three times higher than high-income residents.”
Example One: First Portland Campaign
The first Solarize program took place in Portland, Oregon and was designed to lead the customer from awareness to installation over six months and six steps.
Example Two: Mercer Island Campaigns (2014 and 2018)
The City of Mercer Island, Washington conducted a Solarize campaign in 2014 and again in 2018. The City contracted with Northwest SEED (now Spark Northwest) to provide program management, technical assistance, database management, marketing collateral, and workshop delivery. Funding came from a variety of sources, including grants and utility sponsorships.
The City partnered with local citizens' groups such as Sustainable Mercer Island to enhance promotion and lead generation for the selected solar installer. These local community volunteers also assisted with key campaign tasks, including selecting the solar installer and promoting the campaign through all their networks.
Photo image supplied by City of Mercer Island
2014
Sources of Funding & Amount:
Volunteers: 14
Workshop Attendees: 204
Workshops & Webinars: 5 Site Assessments: 147
Total New Solar Installs: 47
Total kW Installed: 331
Total $ spent locally: $1,336,295
Solarize Discount: 12%
2018
By 2018, with a 30% federal tax rebate plus WA state incentives ongoing, typical payback was still good at approximately 7-8 years. This persuaded the City to run a second campaign. A typical system in 2014 averaged about 7 kW, whereas by 2018, it had increased to 10.5 kW as customers began to power Electric Vehicles. To help residents with up-front costs, local banks and credit unions offered low-interest solar loans. The 2018 campaign ultimately led to 45 more installations.
Example Three: SEEDS II (2017 -2018)
Yale University’s Solar Energy Evolution and Diffusion Studies (SEEDS) II team designed, implemented, and studied Solarize campaigns as a series of randomized field trials in 2017 and 2018.
The following table summarizes the key barriers to action and how each was addressed.
|
Barrier |
How it was addressed |
|
Up-front costs (the top barrier) |
· Reduced solar costs by 20-25%, through group purchasing and reduced installer marketing costs. · For example, before the first Solarize campaign launched, it cost about $27,000 to install a 3-kW system in Portland. A typical system installed the first year of the program cost only about $2,000 after tax credits and incentives · As another example, Connecticut’s Solar for All Campaign, created new incentives specifically for low and middle-income residents, paired solar with energy efficiency upgrades, instituted “no money down, no credit required” offerings, and recruited contractors with experience reaching underserved markets. In three years, this multifaceted approach increased solar penetration in Connecticut’s low-income communities by 188% and helped over 900 low-income households go solar |
|
Lengthy installation |
· Turned the 18 month (on average) process into just 3 to 6 months |
|
Daunting technicalities: process can be overwhelming; analysis paralysis |
· Built supportive community norms and connections, coupled with easy access to experts · Provided free troubleshooting support |
Solarize program achievements have most often been noted in terms of new solar capacity (in kW or MW) from systems installed through the program by the selected contractor. However, this does not account for the fact that some of these purchasers would have installed a solar system even without the program. Nor does it account for any non-selected contractors who also installed more solar systems because of the increased promotion.
Yale University’s SEEDS II team designed, implemented, and studied Solarize campaigns as a series of randomized field trials in 2017 and 2018. That team studied two effects: the rates at which households of various income levels adopted solar, and how different types of messaging interacted with adoption among these groups.
Overall
Based on individual reporting by the organizations involved, the cumulative solar capacity installed through Solarize programs in the U.S.A. by 2021 had a capacity of at least 56,500 kW, or roughly 62,000,000 kWh each year.
|
Location and Proponent |
MW |
|
California (Community Environmental Council – Central Coast) |
3.5 |
|
Connecticut |
8.2 |
|
Georgia |
5 |
|
Midwest Renewable Energy Association’s Grow Solar |
14 |
|
Massachusetts |
16 |
|
Pennsylvania (Philadelphia) |
1.6 |
|
Rhode Island |
2.7 |
|
Solarize Northwest (Washington and Oregon) |
5.5 |
|
TOTAL |
56.5 |
Example One: First Portland Campaign
Within six months of starting the first Solarize campaign in Portland, solar electric photovoltaic (PV) systems had been installed at 120 homes, adding 350 kW of new capacity, and saving roughly 360,000 kWh of conventional electricity per year. The project also helped provide 18 professional wage jobs for site assessors, engineers, project managers, journeyman electricians, and roofers.
Example Two: Mercer Island Campaigns (2014 and 2018)
The Mercer Island 2014 campaign:
The Mercer Island 2018 campaign:

Photo image supplied by Spark Northwest
Example Three: SEEDS II (2017 -2018)
Note: The average peak capacity of a 1kW solar panel in the USA during the time reported was between 2.8 and 4.5 kWh per day (1,022 and 1,643 kWh per year), depending on location. The following analysis assumes a value of only 3 kWh per day (1,095per year), so likely understates the benefits.
The SEEDS II team compared cumulative installations for all Round 8-10 towns (combined) to control towns (combined).
Ross Freeman, Sustainability Manager
City of Mercer Island, WA Ross.freeman@mercerisland.gov www.mercerisland.gov/solarpower
Andrea Axel, Executive Director
Spark Northwest
andrea@sparknorthwest.org http://www.sparknorthwest.org/
Landmark Designation
The program described in this case study was designated in 2021. Designation as a Landmark (best practice) case study through our peer selection process recognizes programs and social marketing approaches considered to be among the most successful in the world. They are nominated both by our peer-selection panels and by Tools of Change staff and are then scored by the selection panels based on impact, innovation, replicability and adaptability.
The panel that designated this program consisted of:
This case study was written by Jay Kassirer in 2021, based on the information in the linked articles, and a review by Ross Freeman and Andrea Axel.
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