Solar solutions

 

BORREGO SPRINGS, A PROGRESSIVE DESERT community located in San Diego County, is well known as a year-round center for astronomy research. In fact, the small town situated on the edge of the Anza-Borrego Desert State Park was designated as California's first International Dark-Sky Community to keep the star gazing sky as clear as possible.

When the community isn't looking to the nighttime stars, its residents are embracing the sun-specifically, the vast potential from solar power. San Diego Gas & Electric (SDG&E) recently received a $10 million grant from the U.S. Department of Energy and the California Energy Commission to build a complex micro-grid project based in Borrego Springs.

Riding it through

Under clear desert skies, SDG&E will test and deploy various smart grid technologies including energy storage, smart meters, energy-management systems and integrated renewable energy generation.

The goal of the three-year project is to demonstrate how to maintain reliability in a more complex grid, leverage distributed resources to benefit the community and electric system, enable more active participation by smart-meter-enabled customers, and maintain power-or "ride through" an outage-even when the larger grid is experiencing problems.

In addition, the federal funding will help to install solar power generators at homes and small businesses, coordinate new peak load management technology, improve overall power quality and integrate and remotely control distributed generation storage devices to allow access to electricity in emergencies. The project will also provide research on the potential impact of electric car charging on the grid.

OMS/DMS laboratory in action

"This project is a `laboratory in action,' where we can see, on a small scale, a version of the smart grid all the way from customer-generated solar power, to battery storage, to automatic power restoration," said Tom Bialek, chief engineer of the smart grid for SDG&E.

Bialek said that SDG&E will also use the project to integrate outage management system/distribution management system (OMS/DMS) into the microgrid operations. The utility will also have the ability to intentionally island all Borrego Springs customers in response to system problems like outages.

A microgrid is essentially a small version of an electric grid that utilizes distributed energy resources and state-of-the-art controls and equipment to enhance grid operation enough to achieve a 15 percent reduction in feeder peak loads, while increasing reliability. Ideally, microgrids promote energy independence within a certain community, potentially allowing ratepayers to be totally sustainable and exit the larger utility grid in favor of power from their own renewables like solar and wind.

Challenges driven by legislation

Driving the Borrego Springs project is California legislation that requires the state's utilities to buy 20 percent of their power from renewable sources like solar and wind. That percentage increases to 30 percent by 2020. Integrating the new energy sources, as well as energy produced by homeowners with solar panels, can be a challenge for utilities, which is why the Borrego Spring project exists.

Assuming that hurdles like energy storage can be ironed out, the microgrid project could have the potential to provide 15 MW of electricity, enough to power the entire Borrego Springs community. At present, 75 homes have installed solar power in the community, with a cumulative output of just under 800 kW. While the solar conversion growth rate for Borrego has not been forecasted, the California Energy Commission's growth forecast for the state calls for solar installs to grow 37.5 percent this year and next. There are currently about 200 MW of solar generation in the California grid.

Coping with the challenges

Like most utilities, SDG&E is trying to cope with the many challenges of smart meter deployment, like how to roll out smart meters and capture customer engagement, how to best plan for distributed resources like solar that can be intermittent at best, especially during San Diego's foggy months, how to convert on a 10-year smart grid plan that includes items that are not even possible yet technology-wise, and how to best evaluate the slew of new technologies headed to the utility market. The purpose of the Borrego Springs microgrid project is to examine all of those issues and much more. For example, during the spring, San Diego is hampered by two months of thick fog, which creates havoc with the utility's ability to process power generated from rooftop solar systems.

"If you know anything about San Diego, we have May Gray and June Gloom coastal fog which travels pretty far inland," said Bialek. "It tends to burn off by noon, but you get little pockets where there are no clouds, and output of PV systems increases dramatically. Then the fog closes back in, creating significant power fluctuations which our voltage regulation equipment tries to keep up with during those short periods of time. So there are issues associated with penetration of PV and we're trying to be pro-active about that." While the integration of all the different IT components and communication systems represents one of the largest challenges in the project, "the real challenge is looking at some of the smart concepts around customer empowerment and trying to get customers to participate in the smart meter program," said Bialek. "Based on their participation level, then you modify the output of generators to compensate for demand."

Multi-technology testing ground

So far, smart meters have been deployed to all 2,800 customers in Borrego Springs. SDG&E is 98 percent complete in rolling out 1.4 million smart meters to its entire customer base. Studies show that smart meters can help homeowners to save between 5 and 15 percent on their utility bills by conserving energy.

At present, two 1.8 MW diesel generators are being retrofitted and will be installed at the substation in August for factory testing. SDG&E has completed an RFP for energy storage components, with expectations that energy storage will be installed during the second quarter of 2012. Homes with existing solar and those that add solar during the course of the project will be equipped with home solar generators. The entire microgrid project is scheduled for completion during the first quarter of 2013.

The Borrego Springs project will also serve as a test ground to define the future technologies needed to effectively run a smart grid and integrate renewable energy sources.

Today, smart meter technology alerts a utility when a customer's power is disrupted. Eventually, technologies will become sophisticated enough to send alerts when a system is about to fail, and remedy a potential problem before it occurs. During this self-healing process, grid switches will automatically re-route power to restore an outage without any human intervention.

For now, that remains a challenge. For example, in the smart grid deployment plan filed recently by SDG&E, technologies do not exist yet to support many of the concepts included for 2015 and beyond. Bialek says that commercially available energy storage options, equipped with the functionality to run certain types of protocols or scenarios, are still a couple of years away.

"There are a lot of concepts there," said Bialek, "but not a lot of hardware or software yet to provide a solution. That's a major challenge for a utility like us. That's why the Borrego Springs project is so important."