The smaller battery is easy to charge at 120 and 240 V. Even with this much smaller charging load, utilities will have to monitor transformer loads. “That’s their business,” says Gross. “You upgrade for air conditioners. You upgrade for flatscreen TVs.” The PEV is just one more appliance.
COMMUNICATIONS
What’s in place for the Smart Grid on the infrastructure side when the Chevy Volt and Nissan Leaf arrive later this year? “At this point, the straight answer is not much,” says Sunil Chhaya, senior manager for PHEV Development Programs at EPRI. “But I need to qualify that because the vehicles are going to be benign to get started with.” Even with annual vehicle sales in the 100,000-plus range, the impact on the total grid will be almost negligible.
In addition to the activities underway to establish future communications (Fig. 2) and security (see “Smart Grid Security”), initial PEVs will come with a dash and wireless (either PC or cellular) interface so consumers know off-peak rates. Armed with that knowledge, consumers can program the PEV in the car. Each automaker takes a different approach.
As an alternative to a fully functional Smart Grid, GM’s Gross says the Chevy Volt can take advantage of the built-in communications capability of OnStar. “With OnStar, we have the ability to get all kinds of information off a vehicle and all kinds of information on a vehicle,” Gross says.
Though OnStar (Fig. 3) isn’t the “do-it-all” desired by GM engineers, they have given lots of consideration to the kind of information they want to send to, and retrieve from, a PEV. The Volt offers GM an alternative to the longer-term potential of connecting a vehicle to the Smart Grid.
Even though GM may have substantial communication with the Volt through the OnStar capability, sharing communications and dialog with the grid and utility companies doesn’t appear likely this year. “But EPRI has an extensive program with General Motors extending both the capabilities on the OnStar side and also adding Smart Grid-specific technologies on the car,” says EPRI’s Chhaya, who is managing the project.
Ford recently announced that it will use Microsoft’s Hohm software so customers can connect to their local utility provider to understand and manage their home’s energy usage. The 2011 Focus Electric will be the first vehicle to use the software. The connectivity should also allow utility companies to better manage the added demands of EVs.
Based on the deployment status of smart meters at the nation’s 3100-plus utility providers, Ford’s Tinskey thinks the Microsoft solution is more than a short-term alternative for today’s Smart Grid. “We believe it’s a long-term solution,” he says.
Instead of communicating directly with smart meters, the approach establishes communication with the utilities’ servers. Since the utilities’ servers already communicate or will communicate with smart meters, the cloud-to-cloud solution avoids all of the diversity issues surrounding today’s smart meters.
The customer can set a timer onboard Nissan’s Leaf to take the best advantage of local utility rates or time-of-use (TOU) rates. “It triggers based on when you know those rates go into effect,” says Nissan’s Perry. This is similar to what people have been doing for other large-current-draw home appliances, such as heating and air-conditioning systems and pool filters. In addition, Leaf owners will be able to remotely control some loads on their vehicles and receive ample information through a cell phone or PC.
The Smart Grid plan for vehicles (Fig. 2 again, bottom) calls for a meter that communicates through a wireless technique, such as ZigBee. To communicate with the HomePlug transceiver in the vehicle, a PLC-ZigBee gateway, perhaps in the electric vehicle supply equipment (EVSE), will provide the bridge.
Any semiconductor technology that winds up on the vehicle must be automotive qualified. That could cause problems if the silicon wasn’t designed to meet the automotive temperature range and other unique automotive requirements that typically go well beyond consumer applications. “All of these manufacturers are a part of SAE J2847, so they are trying to understand the requirements and they are working in that direction. They understand that they need to develop an automotive-grade component,” says GM’s Bellino.
FUTURE POSSIBILITIES
Thanks to all of the efforts being made today, the Smart Grid should strongly interact with the vehicle in perhaps five or 10 years. “I think it’s going to evolve and it’s going to be a smart evolution and features are going to be added one after the other,” says GM’s Gross. One future possibility is the use of PEV batteries to provide storage for the grid and return power under peak load conditions, to be called the Generation 3, or Gen3, Smart Grid.
PRTM’s Hazimeh thinks that many years of PEV experience are required before Gen3 will happen, though. The Nissan Leaf’s 24-kWh lithium-ion battery costs about $600 to $700 per kilowatt-hour, or about $15,000 to $17,000. “You don’t let someone come in and just manage the cycling, taking energy in and out, unless we have enough data to say what is really happening regarding the life of the battery,” says Hazimeh.
Overall, in the short term, the smart consumer charging in an intelligent manner will be a big part of the Smart Grid. “I think that even longer term, it is going to remain consumer-centric,” predicts EPRI’s Chhaya. The premise is that informed customers will make intelligent choices, especially once the rates change from uniform to graded. It will be in their best interest to select the time for charging based on the lowest rate whenever possible.
Therefore, the communication task of carmakers and utilities will be to keep their customers informed and continue working together toward a common energy-saving goal. As Ford’s Tinskey concluded his presentation at Plug-in 2009, “Once our customers begin to make the leap into plug-in vehicles, success of electrification will become a team sport.”