Utility-owned community solar projects are becoming more prevalent across the United States, especially among publicly owned utilities, like the Sacramento Municipal Utility District (SMUD). But solar as a power source presents challenges to utilities as they figure out how to balance the overall amount of power supplied to the grid between traditional sources (like oil, coal and natural gas), and solar. Solar is an inherently variable power source due to the fact that it is only available for generation during daylight hours, and its availability as a power source is subject to weather systems, meaning when it’s cloudy, less electricity is generated. Because solar production is generally higher in the afternoon when the Sun’s rays are most directly overhead, utilities have to reduce their generation from other sources in order to avoid overloading the grid. As the Sun sets in the evening and solar power production decreases, however, the utilities have to ramp up generation from other sources in order to meet the increasing demands resulting from the decreasing supply of solar energy. This results in what is termed a “duck curve,” showing the dip in utility supplied electricity during peak solar generation hours, followed by a large increase (a ramping up) in utility supplied power from other sources in response to the increasing demand (otherwise known as demand response).
Extensible Energy, LLC, is working with the Sacramento Municipal Utility District (SMUD), the Public Service Company of New Mexico (PNM), and other utilities, to develop a new business model to increase the scale, reach, and value of utility-based community solar. Developing utility-based community solar project models that directly address the issue of variability inherent in the use of solar as a power source at the project level minimizes the need for more costly engineering solutions, or region-wide efforts to address integrating solar into the grid, and increase the willingness on the part of the utilities to develop these projects. The “Community Solar Value Project” team will focus on market-ready innovations to increase the overall production value of installed solar by engaging in strategic siting and design, strategic pricing, and enhancement of community solar programs through the integration of complementary technologies such as demand response and storage.
A multi-stakeholder group will create a plan for the commitment of up to 20MW of utility-owned community-based distributed solar generation in SMUD territory by 2020, and will shape a decision framework for utilities replicating the model. A utility forum of interested distribution utilities and industry partners will enhance the decision framework and speed replication.
The use of new approaches to demand response, along with thermal and battery storage, are much talked about as part of the ultimate solution to the duck curve, variability risks, and other symptoms of rising solar penetration. The decision framework that results from this project will open market pathways to such solutions. This project seeks to engage utilities directly with their customers in an effort to increase solar deployment, and increase access to solar as power source, in an effort to strengthen the grid and achieve renewable energy goals.
The Community Solar Value Project Team initiated their project by meeting with SMUD, the primary utility partner, to get approval of a revised enhanced community solar model, as well as to collaborate on the modeling of a few alternatives. The team also formed a utility forum, involving an additional 4-6 utilities to focus on replicable and achievable program designs.
In early summer 2015, the Community Solar Value Project Team hosted a half-dozen other utilities that are working on high-value community solar program designs at a business models workshop. This workshop provided an opportunity to collaborate on addressing integration challenges by looking at various aspects of community solar siting, design, procurement, target marketing and companion measures.
The next steps in the Community Solar Value Project include hosting a one-day workshop focused on the Value of Solar “Triple Play,” meaning community solar plus demand-response and storage companion measures. Other 2015 steps include developing:
In years two and three of the project, the team will provide expert guidance to replicating utilities in how best to adopt and adapt the newly developed community solar model, tested by SMUD, to their own territories. The primary replicating utility will be Public Service of New Mexico; other members of the national utility forum will also replicate the model in whole or in part. The results of initial project and the project replication will be disseminated nationally.