The Lessons of Microgrids
Part of a microgrid - courtesy NREL
Michael Markrich
Microgrids, freestanding electric circuits that produce and store their own electricity and then can distribute it at will, are part of a new movement in grid management. Instead of one large vast electrical grid built on a system of generators that boost electric power and send it out to the far reaches of a community through transmission lines, micro grids enable grid managers to hold some electrical production in reserve and use it when they need it. As climate change has increased the number of hurricanes, floods and wild fires that can take out entire electrical grids for weeks and even months at a time as happened in Puerto Rico- micro grids provide electric power producers and their customers advantages in resilient self sustaining power they never had before .
For example, in Santa Rosa California , the owner of a Chick Fil- A franchise is building his own microgrid. His restaurant is one of only 3 of the 2,700 Atlanta based fast food installing a microgrid but feels he has no alternative. There were 6 power shut offs in California in 2020 as a result of the raging wild fires burning through California more this year. Each year Pacific Gas and Electric is giving “red flag” warnings that outages to protect the grid are going to occur. 2021 looks like it will be even worse. See. https://www.northbaybusinessjournal.com/article/article/solar-energy-upgrades-heat-up-with-chick-fil-a-santa-rosas-microgrid/
Approximately 1/3 of PG and E lines are found in areas with high risk for fires, this includes 5,500 miles of electric lines and 25,500 line miles of distribution assets. When the power goes out it can last for between 19 – 37 hours and affects between 600 - 350,000 customers. https://www.pge.com/pge_global/common/pdfs/safety/emergency-preparedness/natural-disaster/wildfires/wildfire-mitigation-plan/2021-Wildfire-Safety-Plan.pdf page 846.
The reason for the microgrids in California stores according to Stephanie Armistead, a manager for Chick-fil-A’s corporate sustainability program is: “At a moment’s notice, Chick-fil-A operators might have to lock the freezers, purchase dry ice and decide if they need to shut the restaurant down when high winds damage power lines or a heat wave puts too much stress on the existing grid.”
In the past utility managers have not favored microgrids because of the difficulty of integrating power from independent power producers on to their electric power grids. The other reason is economic. As the developer of microgrids- who are also called independent power producers - leave the grid, they take paying customers with them leaving the rest of the grid often to be paid for by the poorest rate payers.
There are still strong and diverging opinions on microgrids. Utility microgrids on small islands in the Caribbean have been able to operate them without the need for fossil fuels, depending just on solar panels and batteries according to the Rocky Mountain Institute. However, larger utilities in cities like New Orleans or Houston require the use of fossil fuel driven natural gas either in microgrids or on their power distribution networks to ensure reliability.
Reliability during natural disasters is important not just to fast food operators but to citizens in individual neighborhoods who fear being without electricity for days if they don’t have their own solar panels. One of those needs is for air conditioning which is power intensive and as the world become hotter ever more important for comfort and health.
The US Army and Navy are developing microgrids. They are becoming a new reality of life in Hawaii and plans are underway to develop them. The lessons of microgrids and resilience will be the subject of the RENEW REBUILD HAWAII ZOOM FORUM on November 16, 2021.
