EVs not so easy

NV Energy will measure transformer loads

Published In: Intelligent Utility Magazine November/December 2010

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Travis Johnson grew up in an engineering family and remembers living at the base of Grand Coulee Dam. Later, he lived near Hoover Dam, where his father worked as an electrical engineer. "I thought engineering was pretty cool," Johnson said.

Johnson earned his own electrical engineering degree and has spent two decades in various roles at NV Energy, which is headquartered in Reno, Nevada. NV Energy serves about 1.2 million electricity customers. That's a 55,000-square-mile service territory serving 97 percent of Nevadans and a bit of California.

Two years ago, reading the tea leaves on electric vehicles (EVs), Johnson pressed for and received his current role as manager of electric transportation and emerging technologies. Now, EVs are here and NV Energy is ready. It will offer its residential customers with smart meters a chance to opt in on time-of-use (TOU) rates, with a one-time chance to opt out after 12 months and return to the traditional flat rate. NV refers to this TOU plan as "an experimental program."

TOU rates will become available to residents as NV Energy rolls out smart meters throughout its territory over the next couple of years. The smart meters also enable NV Energy to serve EV owners. Rather than track the location of EV owners, as Southern California Edison is doing, the utility will map its smart meters to the transformer that serves them and monitor load at that level.

"That'll give us a chance to see how heavily loaded these transformers really are," Johnson said. "The beauty of it is that these cars are going to move around town. People move. People sell cars. What you care about is avoiding having your facilities overloaded. So, as long as you have a way to keep an eye on that, you should be in good shape."

Any attempt to forecast EV uptake in NV Energy's service territory?

"That's really tough," Johnson said. "It's a function of what gasoline prices are going to do and where EV battery costs go. We're hearing some incredibly low figures for next year, from pretty good sources. And gas prices could be all over the map. If gas goes to four dollars a gallon, that could dramatically change consumer interest."

Nevada drivers, like their counterparts across the country, are eligible for a $7,500 tax credit for an EV purchase.

So, what internal, IT-related changes must take place to prepare NV Energy for EV adoption?

Johnson serves as co-chair of the Edison Electric Institute's infrastructure work group, which has identified seven or eight issues that must be resolved.

"One of those issues is load management," Johnson said. "With all this load out there, utilities would be remiss if they didn't consider having the ability to communicate with the vehicles or at least with the charging infrastructure. They might need the ability to shake that load loose for short periods of time.

"Another big challenge is multi-family residences and what we're calling `orphan' locations, which aren't necessarily associated with a home," Johnson continued. "They're not going to be easy. You can imagine the load and the metering racks are not in the best position to accommodate charging stations."

Another issue is determining the "right size" of public charging infrastructure.

"We don't want to over-deploy," Johnson noted. "You don't want to spend a lot of money on infrastructure that may not be necessary."

While most charging will be done at home, Johnson echoed conventional wisdom that somewhat ubiquitous charging stations may have the psychological effect of reassuring drivers with "range anxiety" that they won't become stranded if they miscalculate the length of their drive.

"A colleague of mine said, `People want to see charging infrastructure in their community,'" Johnson said. "'But they don't need it.' It's like a pacifier."

What about the costs and benefits of preparing to serve EV owners?

The load factors at electric utilities in the desert Southwest are not very high, he said. Load factor equals your average load divided by your peak load.

"One benefit of EVs is to improve your load factor, if they charge at night," Johnson said. "They're an ideal use of system capacity."

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