Careful planning of charging station placement could reduce or eliminate the need for new power plants, new study shows — ScienceDaily

National and global plans to combat climate change include increasing the electrification of vehicles and the proportion of electricity produced from renewable sources. However, some forecasts show that these trends may require expensive new power plants to meet peak loads in the evening, when cars are plugged in after the work day. In addition, overproduction of energy from solar farms during the day can waste valuable electricity generation capacity.

In a new study, MIT researchers found that it is possible to mitigate or eliminate both of these problems without the need for advanced technological systems of connected devices and real-time communications, which could increase costs and energy consumption. Instead, encouraging the placement of charging stations for electric vehicles (EVs) in strategic ways, rather than letting them spring up anywhere, and installing systems to start charging the car at delayed times could potentially make a difference.

The study, which will be published in the journal Cell Reports Physical Scienceis by Zachary Needell PhD ’22, Wei Wei postdoc, and Jessika Trancik Professor of MIT’s Institute for Data, Systems, and Society.

In their analysis, the researchers used data collected in two sample cities: New York and Dallas. The data was collected, among other sources, from anonymized records collected through in-vehicle devices and from surveys that carefully sampled populations to capture variable travel behaviors. They showed the times of day cars are used and for how long and how much time the vehicles spend in different kinds of locations — homes, workplaces, shopping, entertainment, and so on.

The findings, Trancik says, “complete the picture about where to strategically place chargers to support EV adoption and also support the electric grid.”

Better availability of charging stations in workplaces, for example, could help absorb the midday peak power generated by solar installations, which might otherwise be lost because it is not economical to build enough battery or other storage capacity to saving all of that for later in the day. Thus, workplace chargers can provide a dual benefit, helping to reduce the evening peak load from EV charging and also making use of solar electricity.

These effects on the electricity system are significant, especially if the system has to meet the charging requirements for a fully electrified fleet of personal vehicles alongside peaks in other electricity demand, for example during the hottest days of the year. If not mitigated, evening peaks in EV charging demand could require the installation of more than 20 percent more power generation capacity, the researchers say.

“Slow charging in the workplace may be more preferable than faster charging technologies for greater use of midday solar resources,” says Wei.

Meanwhile, with delayed home charging, every EV charger could come with a simple app to estimate when its charge cycle will start, so it charges just before it’s needed the next day. Unlike other proposals that require central control of the charging cycle, such a system does not need to communicate information between devices and can be programmed in advance — and can achieve a significant shift in grid demand caused by increasing EV penetration . The reason it works so well, Trancik says, is because of the natural variability in driving behaviors among individuals in a population.

By “home charging,” the researchers aren’t just referring to charging equipment in individual garages or parking lots. They say it is necessary to provide charging stations in on-street parking lots and multi-family parking lots.

Trancik says the findings highlight the value of combining the two measures — charging at work and delayed charging at home — to reduce peak electricity demand, store solar energy and conveniently meet drivers’ charging needs throughout the day. As the team has shown in previous research, home charging can be a particularly effective component of a strategic package of charging sites. Workplace charging, they found, is not a good substitute for home charging to meet the needs of drivers all day.

“Given that there is a lot of public money available to expand charging infrastructure,” Trancik says, “how do you incentivize the site to effectively and efficiently integrate into the power grid without requiring a lot of additional capacity expansion? This research offers some guidance to policymakers about where to focus rules and incentives.

“I think one of the exciting things about these findings is that by being strategic you can avoid a lot of physical infrastructure that you would otherwise need,” he says. “Your electric vehicles can displace some of the need for fixed energy storage, and you can also avoid the need to expand power plant capacity by thinking about the location of chargers as a tool to manage demand — where it occurs and when it occurs.” .

Delayed charging at home could make a surprising difference, the team found. “It basically incentivizes people to start charging later. That might be something that’s pre-programmed into your chargers. You incentivize people to start charging a little bit later, so they’re not all charging at the same time, and it evens out the top.”

Such a program would require some prior commitment on the part of the participants. “You’ll need to have enough people committed to this program up front to avoid investing in physical infrastructure,” says Trancik. “So if you have enough people signing up, then you basically don’t need to build those extra power plants.”

It is not a given that all of these will align properly and creating the right mix of incentives would be crucial. “If you want electric vehicles to function as an efficient solar energy storage technology, then the [EV] The market has to grow fast enough to be able to do that,” says Trancik.

To better use public funds to do this, he says, “you can incentivize charging facilities, which would ideally go through a competitive process — in the private sector, you’d have companies bidding on different projects, but you can incentivize the installation of charging in workplaces, for example, to take advantage of both of these benefits.’ Chargers that people can access when parked near their homes are also important, Trancik adds, but for other reasons. Home charging is one way to meet charging needs, avoiding inconvenient interruptions in people’s travel activities.

The study was supported by the Operational Program for Competitiveness and Internationalization of the European Regional Development Fund, the Regional Operational Program of Lisbon, Portugal and the Portuguese Science and Technology Foundation.

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