Greater wildfire risks prompt growth of electrical ‘microgrids’ to rely less on PG&E

Advanced microgrid controller: An intelligent system that constantly monitors energy loads and resources and manages them to maintain a safe and stable power island. It also can be programmed to save the customer money during normal conditions, using such things as weather forecasts, energy market price information and predictive analytics to optimize energy usage, as well as battery charging and discharging.

Energy storage: Usually made up of batteries, a storage system allows energy, such as from a solar array, to be stored and used when needed. Storage allows the system to go into “island mode” when the larger utility grid is de-energized.

Solar array: A collection of linked solar modules that together can produce enough to meet the power demand of a home or a business.

Utility grid: A traditional electrical distribution system that delivers electricity typically generated by power plants to consumers via high and low voltage transmission lines and substations.

Microgrid: The U.S. Department of Energy defines a it as group of interconnected loads and distributed energy resources within clearly defined electrical boundaries and acting as a single controllable entity with respect to the larger grid. The microgrid can connect and disconnect from the grid, allowing it to operate in “island mode” or in conjunction with a utility distribution system.

In his standard blue jeans and unbuttoned flannel shirt, David Liebman could blend in with many of the young students walking to and from classes at Santa Rosa Junior College.

But Liebman, manager of energy and sustainability for the college district, has something bigger on his mind than class assignments and midterm projects.

Liebman, 27, is heading a $5 million electrical infrastructure project that addresses climate change and fundamentally will transform the way energy is distributed and used on campus.

Using the new solar arrays at the Santa Rosa campus, Liebman is coordinating the development of an electrical microgrid that could operate independently of PG&E during nearby wildfires, or when the escalating threats of fires in the age of climate change prompt the utility to temporarily turn off power.

“Unless we change the infrastructure that runs our society, we're going to be in a lot of trouble because we won't be able to adapt to the significant changes that are happening to both the environment and technology in general,” Liebman said.

Fueled by solar energy and equipped with battery storage and a complex control system, the SRJC project is a small part of a much larger movement environmental experts say could fundamentally flip the paradigm on energy usage here and across the country. Before, massive power plants were turned on to meet demand for electricity; now, microgrids could help do that with available renewable energy such as solar, wind and geothermal.

In Sonoma County, microgrid systems would allow key institutions such as hospitals, municipal utilities, a college campus and certain government agencies to continue to operate in the event of a natural disaster that interrupts PG&E's electrical transmission and distribution.

Local interest in microgrids has heightened with the prospect of Pacific Gas & Electric shutting off power during times of high fire risk.

To provide a model for developing the mini-power networks, a microgrid laboratory has risen just west of the town of Sonoma, at the Stone Edge Farm Estate Vineyards & Winery. The multimillion-dollar microgrid - a testing ground for the latest renewable energy and storage and control technology - encircles 16 acres of vineyards, olive trees and fields of heirloom vegetables and fruit.

A microgrid builder's dream, the property is regularly visited by college students, government officials and experts in renewable energy, and it often inspires more practical possibilities for people like Liebman.

“We're able to be a sandbox for clean technology innovation and a living laboratory where our lessons learned are able to feed into improved energy projects in the future,” said Robert Furber, operations analyst for Wooster Energy Engineering, which designed Stone Edge Farm's microgrid.

Meanwhile, alternative energy advocates say that each microgrid that comes online, with its renewable energy sources, storage capacity and sophisticated control systems, makes the larger electrical power grid less reliant on fossil fuel power plants.

Breaking ‘utility model'

“It breaks the utility model,” Liebman said. “The utility can no longer be a centralized authority for electricity generation. This is going to shift a lot of the utilities into poles and wire companies that manage the distribution grid.”

Liebman said advances in renewable energy, battery storage technology and smart grid controls are helping pave the way to a future when every household, building or property has the potential to be an energy generator, user and mini-grid operator.

At the Santa Rosa campus, Liebman's project, funded by a grant from the California Energy Commission, would require the addition of two more batteries specialized for use in microgrids. The campus currently has a 1-megawatt Tesla battery system for storage.

The Tesla battery system cost roughly $1.6 million and was acquired with money from the college district's $410 million Measure H facilities bond voters approved in 2014 for new construction and other campus projects. SRJC also bought the new solar arrays with Measure H funds. The cost of the battery was partly offset by an $800,000 rebate from the state.

The single Tesla battery, operating without extra battery storage and an advanced microgrid control system, is currently being used to help meet peak electricity demand at the campus.

When the microgrid is fully built, the system will allow the campus to optimize its daily electricity consumption, taking into account such things as demand and the cost of power. It also will allow the campus to become a stable point in the larger utility grid, using electricity smarter and more efficiently, plus storing excess energy for discharge into the PG&E grid when needed.