Research contributions to shared solar:

Catalyzing community-led solar: How using the CSOS model can catalyze shared solar development by enabling collective action

Influences on community solar development: An analysis to determine which factors are most influential to the development of a shared solar project

Catalyzing community-led solar onboarding

Research on catalyzing community solar development through collective action with the CSOS model


Community solar’s relationship to collective action

Community solar projects may share the same energy conversion technology as traditional residential, commercial, or utility scale solar, but the process of developing community solar is inherently different. While design demands of traditional solar can be constrained by a single entity, shared solar must accommodate the interests of many, potentially diverse, parties. As a result, community solar presents a collective action problem: individual agents coming together in order to pursue a mutually beneficial goal. Nobel prize laureate Elinor Ostrom famously explored applications of collective action in common pool resources; Ostrom’s work adopts the key assumption collective action is not straight forward to achieve. In other words, a mutually beneficial goal may not be sufficient to cause individuals to see themselves as a group and work towards a joint project. Modern collective action theory is particularly troubling to community solar development because every shared solar project, to some degree, will require independent entities to jointly collaborate, design, and purchase a single solar array.

In some cases, the economic potential of shared solar is significant enough that minimal motivation is necessary for individuals to “solve” the collective action problem and develop a shared solar project. Financial gain to this extent typically requires virtual net-metering (VNM): a practice which allows users to connect their portion of the shared solar array with their household meter. Unfortunately, VNM is limited or completely disallowed by most utilities in the United States. In the absence of VNM, the economic potential of community solar is impaired. In this case, more modest financial returns can prevent independents from achieving a group oriented end. With VNM options available in only a few locations in the country, methods for promoting collective action are integral for the development of community solar.

Figure 1. Net-meter and virtual net-meter comparison diagram.


CSOS as a catalyst for collective action and project development

Community Solar on State (CSOS) represented an innovative attempt by experts to assemble shared solar in a region with restrictive VNM policy and competitive electricity prices. While the CSOS workshop series did not result in the anticipated university-community solar project, it was successful in an exciting new direction. Analysis of the project outcomes suggest that the Community Solar on State model was influential in the development of a local community-led solar project. Remarkably, CSOS acted as a catalyst for collective action which propelled a utility-scale solar array into a region without VNM. The CSOS catalyst model can be refined and applied to any community or network to catalyze collective action and drive shared solar development.

Figure 2. CSOS connection to current solar infrustructure.

Theories of group agency are instrumental for understanding how the success of the CSOS model is relevant to collective action. List and Petit define an agent in a system as possessing representational, motivational, and capacitive states. The representational state depicts the environment, the motivational state specifies the preferred environment, and capacitive state is the ability to intervene in order to align representational and motivational states. A group agent is then a “group” which exhibits the three qualities of agency. It is useful to visualize shared solar projects through this lens. The community solar group, as a whole, will note the lack of shared solar project in the vicinity (representation), unified by preferring the existence of such a project (motivation), and by some means - financial, regional authority, voting power, etc. - have the ability to achieve this preference (capacity). The establishment of a group agent is an essential component to successful collective action; the independent agents must be able to see themselves as parts of a group in order to appreciate the shared goal and work together.

CSOS was able to initiate collective action by developing the workshop series through the very mechanisms that establish agency (representation, motivation, and capacity). The workshops attempted integrative design: a process which values stakeholders’ opinions and designs the optimal project in compliance with their shared identity. As opposed to starting a project around ideas of concept or system design, integrative design argues that in order to maximize the clients’ solar utility, the development process should commence by aligning the stakeholders’ shared beliefs, philosophies, and principles.

Figure 3. Carol Sanford framework for integrative design used by Community Solar on State

A belief was defined as how one understands the world to work, similar to the representational state of agency. Principles guide stakeholders to action, much like an agent’s motivational state. A philosophy was the role the stakeholder plays within the system, and this can also be represented as capacity: the agent’s ability to alter the system. Recall that representative, motivational, and capacitive states define group agency; CSOS was able to establish a group agent by uniting stakeholders around the fundamental mechanisms of agency.

Figure 4. Integrative design parallels the qualities that establish agency.

The accelerated development of a group agent oriented around community-led solar successfully catalyzed collective action. Collective action is an integral, often absent, element to community solar development. Applying the CSOS model to catalyze collective action from a group agent fills a void in project development, and this process can significantly facilitate the development of community solar despite inhibiting VNM restrictions.


Community solar "onboarding" catalyst

In the aftermath of CSOS, analysis suggests the successful results do not have to be a unique occurrence. The integrative design process practiced through the CSOS workshops is a repeatable framework that can be applied to any region or group of stakeholders. The "community solar onboarding catalyst" can be simplified to the follwoing structure depicted in Figure 5: Integrative design is practiced within a group of stakeholders by the Community Solar on State (CSOS) workshops. A group agent is generated from the workshops, and then determines the optiminal solar project serving the community of represented stakeholders. Finally, the group agent achieves collective action by implementing the solar design. 

Figure 5. Progression from Integrative Design to Collective Action through Agency.

By using CSOS-integrative design model, the collective action barrier is mitigated. The catalyst provides an effective onboarding process for stakeholders which allows for (1) more projects to come into existence, (2) develop at a faster pace, and (3) more optimally serive the comnunity of stakeholders. The onboarding catalyst does not seek to alter the beleifs of the community, but instead uses their shared-identity as a strength. Therefore, onboarding through the CSOS model is named a "catalyst" because it facilitates an accelerated product without fundamentally changing the ingredients (Figure 6).

Figure 6. The onboarding catalyst metaphor.

Influences on community solar development

Adapted from research by Jesse Cohen and Dr. Jeffrey Brownson (2015).


Community solar has been described as a solar development method able to provide access to a wider portfolio of investors (e.g. those who live in apartment buildings), but many factors contribute to development of a shared solar project. Cohen and Brownson set out to determine which factors are most influential to community solar, and from their efforts, established regions most applicable for projects.

The following factors were analyzed:

  • Solar resource: how much “sun” is reaching the array
  • Alternative prices: the local price of other electricity sources
  • Government intervention: policies or regulations set by a level of government (may have positive or negative impacts)

Each of these factors were compared to a map of shared solar projects (Figure 1) to determine their relative influence.

Figure 1. Map of shared solar projects in the U.S. (Community Solar Hub, 2017)


Solar Resource

The solar resource map below (Figure 2) represents data collected by the National Renewable Energy Lab (NREL) demonstrating the relative amount of solar energy incident across the United States. As one may have assumed, southern states generally receive more intense solar resource, but it is also true that western states typically receive more solar irradiation than their eastern counterparts.

Figure 2. Solar resource in the United States (courtesy: Billy J. Roberts and NREL)

What may be surprising is that the difference in annual electricity which can be generated between regions is less than it seems. Data from the table below shows that the difference in solar potential between Orlando and Sacramento is negligible, and even the central Pennsylvanian city Harrisburg obtains over 80% of the solar that is irradiant over most of California.


Annual solar resource

Percentage of CA

Sacramento, CA

1,623 kWh/kW


Orlando, FL

1,606 kWh/kW


Harrisburg, PA

1,313 kWh/kW


Table 1. Comparing the solar resource in the U.S. (NREL, 2017)

An intuitive guess may conclude that a greater solar resource provides a significant advantage for community solar, but a review of the current shared solar projects suggests this is not the case. Washington (6), a state known for clouds and rain, has twice as many shared solar plants as California (3), a notoriously sunny state. Massachusetts (11) and Minnesota (7) are two of the nation’s leaders, while Texas (2), Florida (2), and New Mexico (1) struggle to have an impact.


Shared solar projects















New Mexico


Table 2. Various states and their shared solar projects (Community Solar Hub, 2017)

Although the south western states may have the greatest solar resource, the amount of solar energy is still comparable to most parts of the nation. Interestingly, shared solar projects appear to be distributed largely independent of the solar resource; many concentrations of projects are located in the north east with some of the “weakest” resource in the nation. It is clear there are more powerful factors in determining a viable site for community solar.


Alternative Prices

As suggested by Brownson in Solar Energy Conversion Systems, the price of alternatives is often a more accurate means of gauging the potential for a solar project. Alternatives represent the other options a consumer has to receive the same service. For solar photovoltaics, this is typically electricity from coal, natural gas, or even hydropower, that is distributed by the utility. When the alternative price is high, it is more likely that solar will be successful in the locale because solar will provide financial savings. When the price of alternatives is competitive, it is more difficult for the solar technology generate an impact. In other words, people will seek out other means of electricity (e.g. solar) if they feel their bill is too expensive.

Residential electricity rates from some cities are listed below in Figure 3; these prices are positioned over the amount of community solar projects that are located in the state. Figure 3 exemplifies a clear trend: In states with high electricity prices, community solar is more popular.

Figure 3. Comparing concentrations of shared solar projects with local electricity prices (NREL, 2017) (Community Solar Hub, 2017)

The concept that solar is more abundant where alternatives are expensive is not surprising, but the extent in which alternative price impacts community solar is significant. With just a few cents/kWh rise in electricity, shared solar quickly becomes a solution groups are pursuing. The trend is not perfect because there are other determinants for community solar, but local electricity prices certainly play a notable role in the development of shared solar.


Government Interest in Solar

Government intervention with solar can have a positive or negative effect on solar development. Sometimes local governments impose harsh capacity limits or require arduous permitting processes which slow or even completely halt solar installations. Other times, multiple levels of government will present large tax credits or rebates to offset the initial investment. Although the solar industry is rapidly maturing and can generally support itself, the government, for better or worse, is currently a crucial component to solar development.

Most solar policies impact traditional solar and shared solar alike. However, Cohen and Brownson identified one policy that particularly targets community solar: virtual net-metering (VNM). Virtual net-meters allow community solar owners to experience the benefits of net-metering (an extremely common practice for solar) (Figure 4). Without net-meters, the economics of a solar array are often compromised.

Figure 4. Net-meter versus a virtual net-meter.

Unfortunately, VNM is not a standard offering from utilities and rarely exists. Yet, some state governments require utilities to provide a VNM option for consumers. In 2015, the Center for Sustainable Energy compiled a list of states with VNM options for solar. The top three community solar producing states each have strong VNM policies established at a state level. Additionally, out of the 24 states that do not register a single shared solar project, almost none have a coherent VNM policy for residential consumers.

National Rank


Number of projects














Table 3. States with the highest concentration of community solar (Solar Market Pathways, 2015) (Community Solar Hub, 2017)

Analysis shows that VNM is not the only element necessary for community solar, but it is one of the most common characteristics shared among projects. Community solar is far more likely in states that allow VNM, and far rarer in states without such mandates. Innovative research projects engineering alternative methods VNM to facilitate the development of community solar, but for now, VNM is a significant influence on community solar.


Study conclusions

Restrictions to community solar are not physical; they are inherent to the local markets and government policy. The difference in the solar resource, even the north east to the south west of the country, is less than many would assume. There is plenty of sunshine all across the nation for solar to thrive. Many locations that pursued community solar also have expensive utility rates, and it is likely that community solar will continue to rise in locations wishing to avoid high electricity prices. Finally, states with VNM are generally the hosts for community solar. VNM allows shared solar to be very competitive, and most community solar projects have this practice in place.

Summary of conclusions

  • Solar resource has negligible impact on community solar development
  • Community solar is more popular in regions with high priced electricity alternatives
  • Virtual net-metering (VNM) is a common component of successful shared solar projects
    • Governments that set VNM mechanisms experience the greatest concentrations of shared solar projects.

With these conclusions, regions primed for community solar development can be identified. A promising shared solar project is most likely to be successful in a region with (1) above average electricity prices and (2) a supportive government that establishes a statewide VNM process.

Community solar can still develop regions outside this criteria (see: the UAJA 2.6 MW community-led project), but these projects face an uphill battle. Engineers are developing new methods to enable community solar in regions without VNM (see: Catalyzing community-led solar or the Community Solar on State Workshops) so that all communities can participate in the shared solar experience!



Bronwson, J.R. (2014) Solar Energy Conversion Systems (First ed.). Oxford, U.K.: Academic Press. Elsevier Inc. ISBN-13: 978-0-12-397021-3


Community Solar Hub. (2017). Community Solar Project Map. (S. Shot, Producer, & U.S. Department of Energy) Retrieved from Community Solar Hub:

NREL. (2017). Systems Advisor Model (SAM). 2017.1.17. Golden, Colorado : U.S. Department of Energy.

Solar Market Pathways. (2015). Virtual Net Metering Policy Background and Tariff Summary Report. Center for Sustainable Energy, California Solar Energy Industries Association, Interstate Renewable Energy Council. Center for Sustainable Energy.

Blockchain integrated community solar: Enabling access to solar goods and services for low-income stakeholders

in progress