With mainstream EVs entering the market in the next year, utilities are worried about cars plugging into the grid en masse. To anticipate and handle those overwhelming spurts of power demand, they are looking to infrastructure upgrades, networked management systems and customer education.
One problem with electric vehicles is that they won’t necessarily be plug-and-play, as buyers might expect. “You won’t be able to buy the car on Saturday, and plug it in Saturday night,” said Michael Harrigan, VP of electric vehicle services for NRG Energy. Users will need to install a permanently wired charging station in their home. “This idea of installing a piece of equipment isn’t as simple as bringing in a new refrigerator or something like that,” he added. Charging stations will be a massive undertaking, which is part of why Harrigan left Tesla to work on the problem on a greater scale, he said. (NRG is currently working to electrify Houston, which Harrigan said it well-suited to electric cars due to it being large, new and spread out, requiring commuting by driving.)
A transformer generally serves 10 homes, said Pedro Pizzarro, EVP of power operations for Southern Cailfornia Edison. An electric vehicle’s peak load could be as much as a half to a whole house. “If you get three, four, five plug-in vehicles on the same block, we need a new distribution service to serve it. Right now that takes 30-50 days.” Pizzarro said he is working to smooth the process of obtaining permits with the aim of reducing that time period to a week or less.
But readying the grid for EVs brings a lot of unknowns. For instance, Pizzarro asked: “What is a threshold level beyond which customers need to be responsible and below which is network infrastructure?” Some things utilities may want to be more hands-off on, like the open architecture for smart metering tools. But clearly the utilities want to maintain control over reliability, safety and stability of power, Pizzarro said.
Another big issue is the fact that while electric cars may plug into the grid, they don’t stay in the grid. “As you drive your electric car around it’s not like your house, it goes from service of area to service area — hopefully soon coast to coast,” said Harrigan. “We foresee a time when we have an open network like the Internet or a clearinghouse network like Cirrus for ATMs.” That network will handle cross-billing, direct communication with cars to understand how low on power they are, and forecasting for when cars will be driven next.
That issue of when people charge is critical. For EVs to play their role in decreasing greenhouse gas emissions, they need to not put undue load on power. Pizzaro said at SC Edison peak usage is double average usage. In order to address peak usage, SC Edison has contracts with additional plants, many of them using natural gas and therefore emitting additional greenhouse gas. Minimizing the negative impact of plugging into the grid will necessitate careful demand management, including office plug-in facilities and charging infrastructure for rain and housing without garages, Pizzarro said.