This week’s guest writer is John Bernhardt, Outreach & Communications Director, Clean Coalition, discussing the rapid evolution of microgrid models in the USA.

The United States is transitioning from a centralized power system towards a more decentralized system. As greater amounts of distributed energy resources (DER) – such as local renewables, advanced inverters, and energy storage – come online, it is vital to establish an approach that optimizes the integration of these solutions in a manner that secures the most value to the grid at the least cost. The Clean Coalition’s Community Microgrid Initiative is providing such a pathway.

A Community Microgrid is a coordinated local grid area served by one or more distribution substations and supported by high penetrations of distributed generation (DG) and other DER. Community Microgrids reflect a new approach for grid operations that achieve a more sustainable, secure, and cost-effective energy system while enabling long-term power backup for prioritized loads.  The substation-level foundation of a Community Microgrid facilitates cost-effective replication for optimizing grid operations and customer satisfaction across utility service territories.

In collaboration with leading utilities, the Clean Coalition is developing Community Microgrids to demonstrate their technical and economic viability. The objective of this work is three-fold:

  • Achieve high penetrations of local renewable energy generation
  • Enhance grid resilience by providing long-term back-up power for critical loads
  • Establish a replicable model that enables scale and cost-effectiveness for any target grid area

The Clean Coalition has established a standardized four-step process to design and deploy these microgrids.

First, a DG survey assesses the potential for local generation within the target grid area. Tailored to the specific distribution grid area, the DG Survey takes into account the characteristics of actual prospective sites for local renewable generation. DG potential is quantified, which also helps define potential needs for other DER.

Second is the creation of a DER optimization model. The DER optimization model defines the ideal portfolios of DER across a target grid area. This step uses utility-validated advanced grid modeling techniques that consider local grid characteristics such as power flow, connected feeder capacity, and customer load shapes. This methodology became a key component of California’s recent ruling that requires the state’s investor-owned utilities to plan for high penetrations of DER, leveraging existing distribution grid capacity to accelerate deployment.

Third, a DER financial analysis highlights the costs and benefits of the optimal DER portfolios, including the value of reduced transmission and distribution investments, transmission access charges, and line losses. This analysis takes into account the use of efficient markets based on streamlined procurement and interconnection of DER.

The final step is to create a design and deployment plan for the Community Microgrid. Working in collaboration with local utilities, the Clean Coalition’s system design and operational plan includes technology vendor recommendations relevant to the design criteria and grid requirements.

The Clean Coalition is actively pushing forward two Community Microgrids. In collaboration with Pacific Gas & Electric, the Hunters Point Community Microgrid Project is bringing 50 megawatts of local solar PV to one substation area in San Francisco. In New York, two utilities – PSEG Long Island and the Long Island Power Authority – are deploying a combination of solar and storage in the Long Island Community Microgrid Project. This project was recently awarded NY Prize funding.