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Much of the nation’s vehicle fleet could be converted to run on electricity with hardly a ripple felt by the power grid, according to recent findings by the Rocky Mountain Institute.
But a key factor is whether utilities and other developers locate charging stations in places that tap into the excess capacity now readily available on the grid.
Converting all of the nation’s “light” vehicles from gasoline to electricity likely would hike the demand for power by about 25 percent nationwide, according to Chris Nelder, a manager with the Institute’s electricity practice. He is one of three authors of the study assessing the probable impact of vehicle charging on the grid.
“We can accommodate all these (electric vehicles) on the grid without increasing the cost of electricity, even though it is a pretty substantial load,” Nelder said. “We think that that additional load could be accommodated without increasing peak generation capacity. And we think we can do it without … building a lot of new generation and transmission and distribution equipment.”
But achieving all of that, he cautioned, would require utilities and third-party developers to be strategic in deciding where to locate charging stations. It also would require a rate design that encourages vehicle owners to charge their car batteries when the grid has capacity to spare.
‘Soak up extra generation’
Properly aligning this new demand with excess capacity first requires determining when a utility can produce more power than it needs. That varies quite a bit, depending on both demand and supply factors, Nelder said.
In the Midwest — with its abundance of wind turbines that typically produce at night — the overnight hours provide plenty of extra power. In California and other areas with abundant sunshine and solar panels, he said, production is more likely to peak in the mid-afternoon.
Already, Nelder said, “Solar now is sometimes being curtailed because there isn’t enough demand for it. In some cases, power prices are going negative. There’s the perfect opportunity to charge vehicles and soak up excess generation.”
Taking advantage of that excess capacity would require having charging stations in the right places, Nelder said.
In California, for example, encouraging charging in the afternoon probably means making charging stations available at workplaces and stores. In the windy Midwest, charging stations should be available where people are sleeping, Nelder said.
However, it wouldn’t necessarily be easy to locate charging stations where they would be used most efficiently.
“You need coordination with other stakeholders to get those charging stations where you need them,” Nelder said. “You may need people who own shopping centers to work with you. You’ll need regulator support and people from city development departments. It’s a whole constellation of people who may or may not be used to working together.”
And if strategic locations are one factor ushering electric-vehicle load into off-peak hours, time-of-use rates are another.
Nelder and his colleagues believe it’s critical that rates be structured to reward off-peak vehicle charging with reduced prices.
Electric vehicles have not made extensive inroads yet, but they are likely to do so soon, according to the Rocky Mountain Institute analysis. Nelder said it’s urgent that utilities and state regulators begin planning how to develop this new infrastructure in a way that will make the best possible use of existing grid assets, and minimize the need for upgrades and additions.
“If you manage the load of EV charging so it happens at the right place and time, you can optimize all existing assets on the grid. Instead of having big peaks and valleys, you can use EVs to flatten out that curve. In so doing, you will optimize and extend the life of all these other assets,” Nelder said.
Midwest infrastructure growing
Although electric-vehicle activity is concentrated in California, some Midwest utilities are expanding their electric-vehicle infrastructure. Kansas City Power & Light, for example, has installed about 600 charging stations in its service territory. Another 500 or so are likely to be installed later this year.
The utility is making a point of installing the chargers “in places where we have extra capacity,” said spokesperson Courtney Hughly. “If there’s a need for a charging station where the grid is at capacity, we can look and see if (there are) other ways to address that need.”
So far, electric-vehicle owners tend to use KCPL’s public charging stations for just enough juice to get them to the next charging station. The bulk of their charging is done at home overnight, allowing the utility “to be more efficient in the way we use our grid,” Hughly said.
Nelder sees state regulators as having a crucial role in ensuring that charging networks are developed in a way that makes the most efficient use of the grid. Utilities may not be invested in optimizing use of the grid or, in a regulated marketplace, might even have an incentive to direct charging to the peak hours when they could charge more per kilowatt-hour.
Nelder said that regulators need to closely monitor the development of these charging networks.
“Will the regulator say, ‘Just give us the cost and you can rate-base it?’ The regulator should make sure the utilities put chargers in the right places. The utilities should base compensation on performance,” Nelder said. “For example, utilities might win a financial incentive only if they install chargers that are used a lot. So the regulator could say to the utility, ‘We’ll give you an incentive, but only if the chargers you install are heavily used and highly effective.’ ”
If third parties develop charging stations, they still will need to plug into the local utility’s distribution system. Whether the utility simply provides a connection to the station or owns and operates it, Nelder said its compensation should be related to how much the stations are used and how well they fit into the larger grid picture.
Nelder said he’s concerned that “a lot of utilities are not thinking about this at all. Their regulators aren’t giving them any guidance on it. We think a lot of them are dangerously unaware of what might hit them. That’s why we wrote the paper: You guys need to sit up and pay attention.”