Microgrids avoid fossil fuels and keep solar running in an outage


After three years of massive wildfires and Pacific Gas & Electric’s implementation of a public safety power shutoff program last year, the concept of creating more energy independence and resiliency through microgrids is picking up momentum in West Marin.

First, what is a microgrid? The key distinguishing feature of a microgrid is the ability it lends to consumers to stay powered when the larger utility grid network goes down. In the past, the standard solution for increasing resiliency was a back-up generator, typically burning diesel, propane or natural gas fuel. Sales of such emergency power units have gone through the roof as residents, businesses and critical facilities cope with recurring outages.

As California joins a growing list of states establishing longer-term 100-percent clean energy targets, there is a clash. While California looks to phase out all fossil fuels, state citizens are increasingly relying upon emergency generators, often unregulated, burning fossil fuels to keep the lights on during outages. Ironically enough, these generators can actually increase fire risk due to improper fuel storage, lack of proper maintenance and inadequate safety protections as residents take their energy future into their own hands.

The state, and particularly its remote regions such as West Marin, are clearly in a conundrum. California added 7,228 megawatts of primarily rooftop solar systems—enough electricity to power over 7 million efficient California homes—between 2007 and 2018. Yet most of this clean renewable energy is not available during power outages. 

Due to longstanding safety protocols, the vast majority of the solar photovoltaic technology deployed to date shuts off when the larger distribution grid goes down.

Yet if these solar panels were integrated with batteries, equipped with special transfer switches, and perhaps backed up by generators, they could indeed provide power during utility outages via a microgrid. That’s the strategy communities such as Stinson Beach are pursuing, where the fire station and the adjacent community center already have solar and back-up generators in place. Vendors are currently providing estimates for the cost of installing batteries and controls that allow each energy source to communicate with one another. 

As reported recently in the Light, the Shoreline Unified School District is exploring a microgrid in Tomales with CleanSpark, a vendor that has built successful microgrids for the military. Commonweal, on the outskirts of Bolinas, is also looking into installing a large solar array with a future microgrid in mind. The Dance Palace in Point Reyes Station created a simple microgrid over a decade ago.  

What does a microgrid cost?

I’ve been doing a series of interviews on KWMR to educate West Marin about the need for microgrids. The most common question is, “What does a microgrid cost?” The best answer: “It depends.” Data compiled for the California Energy Commission shows that the average cost of 26 microgrids was $3 million per megawatt. A system of that size could power 1,000 California homes. Nevertheless, most microgrids are retrofits. The more infrastructure already in place at a microgrid site, the lower the cost of creating a microgrid. Residences with existing solar arrays can expect to pay between $10,000 and $20,000 to add batteries and create a microgrid, for example. The cost depends on the size of the house, its level of energy efficiency and the size of the battery. 

How to fund a microgrid

County and state funds are now available for batteries and microgrids. Marin Clean Energy, for example, announced late last year that it had earmarked $3 million for local resiliency to help cover the costs of batteries. Yet more research is needed to know what funds might be available for West Marin communities. According to Tom Willard of Sage Renewables, any battery for a microgrid in Bolinas would not be eligible since Marin Clean Energy wants to be able to use the batteries it invests in to provide value to its broader supply portfolio. There is apparently not enough room on the current PG&E grid serving Bolinas to send any electricity back to east Marin to meet this requirement. 

State funding is available if a microgrid is located in an area where the fire threat is considered tier two or tier three. Under this criterion, Bolinas may not be eligible, but Stinson Beach probably is. 

The program, known as the Self-Generation Incentive Program, recently increased available funding from $100 million to $613 million under an “equity resiliency incentive” program that in many cases could cover the complete cost of a new battery. Visit cpuc.ca.gov/sgip to learn more about the initiative, and check cpuc.ca.gov/FireThreatMaps for eligibility. Applications for home systems are due Feb. 18; all other applicants face an April 1 submission deadline. 

Finally, many private companies are now offering no-cash-down financing for microgrids. These may be particularly appealing to small public agencies unable to take advantage of tax credits for solar or batteries. 

Want to learn more? Please come to the Environmental Forum of Marin’s “Community Microgrids: Renewable Energy and Resilience” on Feb. 4 at the Corte Madera Community Center. Doors open at 6 p.m. For more information, visit MarinEFM.org. 


Peter Asmus, a research director for Navigant Research, has been leading global microgrid research for the past decade. He lives in Stinson Beach.