ENERGY: Utilities use cities to test power future

SDG&E and Southern California Edison get ready for renewable energy

Alan Dulgeroff, SDG&E's manager of a smart grid testing project scheduled to be installed in Borrego Springs next year, stands next to a server last week at SDG&E's Kearny Mesa building. The server will be installed in Borrego Springs to help manage the electric grid. (Photo by Eric Wolff Staff Writer)

 
Borrego Springs, population 2,535, a small town on the edge of Anza-Borrego Desert State Park, will soon join the suburban planned community of Irvine, population 219,793, as a launching pad of the electric grid of the future.

The two sites will serve as electric distribution laboratories to help Southern California Edison and San Diego Gas & Electric Co. solve the challenges inherent in adding solar panels and wind turbines into the electricity generation mix.

"We'll see more change on the electric grid in the next 20 years than we saw in the last 100," said Alan Dulgeroff, director of smart grid projects for SDG&E.

For a century, the electricity transmission system for San Diego and Riverside counties remained essentially unchanged: Power produced by fossil-fuel-burning generators flowed in one direction to the utility's customers.

But as of this year, state regulations require California's utilities to buy 20 percent of their power from renewable sources, such as wind turbines and solar panels, and by 2020 that proportion must rise to 30 percent.

Renewable energy comes with challenges: Cloud cover can send the output from a solar farm plummeting, and a spike in wind speed causes a corresponding spike in power generated by a turbine. Either way, the utilities must find a way to smooth these fluctuations to keep a steady stream of electrons heading into customers' homes. Mix in the added complication of customers producing their own electricity through rooftop solar panels, and the way utilities manage electricity must change dramatically.

In an effort to solve these problems, both power companies have developed testing areas for their versions of the electric grid of the future. Southern California Edison has several test circuits in its service area, including a major one in Irvine, and SDG&E plans to install a test bed in Borrego Springs starting at the end of this year.

"The micro-grid is a petri dish for what we'll build across our energy system," Dulgeroff said.

The plans for the test areas are similar: Experiment with "self-healing" in the event of damage to part of the grid, set up batteries to help with the smoothing and install home area networks that would make it easier for utilities and customers to adjust their power use, known in the industry as electricity demand.

Traditionally, the only variable in the grid was electricity usage: When a customer turns on a light, the utility has to crank up generators a bit to meet that demand. But the equation was relatively easy to manage because the utility had absolute control of its generators.

"Now when you're bringing in solar and wind, you're bringing in added sources of variability to the system," said Virginia Lacy, a consultant with the Rocky Mountain Institute, an energy nonprofit.

Finding ways to keep supply and demand balanced when both are constantly shifting is tricky.

A crucial piece of the solution is batteries, which would allow the utilities to store overproduction of electricity and instantly fill gaps when the sun shines less brightly.

"Energy storage is the holy grail of electricity," Dulgeroff said.

At their test sites, the utilities plan to put batteries on homes with solar panels. The batteries won't be big enough to supply electricity to the home all night, but they'll be able to fill gaps in power supplied from the panels during the day, and also provide some emergency electricity supply back to the grid itself when needed.

SDG&E plans to install a big battery at its substation to insulate Borrego Springs against short blackouts or brownouts caused by problems from the rest of the region.

Edison intends to put an 8 megawatt battery at its Tehachapi Wind Farm, said Mike Montoya, the utility's director of grid advancement. The plant sometimes generates more power than the grid needs from it at night, when demand is low. Storing the excess power in the battery would allow Edison an instant backup if wind generation falls at a time when it's needed.

"It increases system reliability, provides system capacity and smooths the intermittency of the generation," Montoya said.

But even if supply is variable, so is demand.

On today's grid, people run their air conditioners without regard for time of day or electricity supply. At Borrego Springs, Dulgeroff said they'll install home networks that would allow homeowners to manage their power use on an individual level.

SDG&E would monitor grid load on hot days, and when demand is too high, officials might contact homeowners with an automated message to ask them to reduce the amount of power they are using.

"Part of what we're doing here is looking at how customers respond to different requests," Dulgeroff said.

Borrego Springs, located at the terminus of SDG&E's grid, also presents an ideal opportunity to test "islanding" or "self-healing" in the event of damage to the system. By installing powerful computers at the substation and automated switches at transformers and other junction points on the grid, SDG&E officials want to see whether they can keep Borrego Springs running when other parts of the system have blackouts.

Edison is looking at similar technology in Irvine.

"If a car runs into a pole, we want to minimize the number of homes that have a disruption," Montoya said.

The utilities are testing a variety of other technologies and systems as they change gears from what they've done for a long time. The adjustment won't just be about physical systems.

"There's going to be a lot of training," said Rocky Mountain Institute's Lacy. "And the changing of mental models."

Call staff writer Eric Wolff at 760-740-5412.

source:  http://www.nctimes.com/business/article_e1275848-0278-586b-961e-f4be0e1fe314.html