According to new research, strategically locating EV charging stations and implementing mechanisms to commence charging at later time might reduce or eliminate the need for new power plants.
National and global climate change initiatives include boosting car electrification and the share of power generated from renewable sources. Yet, some forecasts indicate that these developments may need the construction of costly new power plants to satisfy peak loads in the evening when automobiles are plugged in after work. Moreover, solar farm overproduction throughout the day might squander important electricity generation capacity.
In a new study, MIT researchers have found that it’s possible to mitigate or eliminate both these problems without the need for advanced technological systems of connected devices and real-time communications, which could add to costs and energy consumption. Instead, encouraging the placing of charging stations for electric vehicles (EVs) in strategic ways, rather than letting them spring up anywhere, and setting up systems to initiate car charging at delayed times could potentially make all the difference.
The study, which will be published in the journal Cell Reports Physical Science, is by Zachary Needell PhD ‘22, postdoc Wei Wei, and Professor Jessika Trancik 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 findings, Trancik says, “round out the picture on the question of where to strategically locate chargers to support EV adoption and also support the power grid.”
Better availability of charging stations at workplaces, for example, could help to soak up peak power being produced at midday from solar power installations, which might otherwise go to waste because it is not economical to build enough battery or other storage capacity to save all of it for later in the day.
Thus, workplace chargers can provide a double benefit, helping to reduce the evening peak load from EV charging and also making use of solar electricity output.
These effects on the electric power system are considerable, especially if the system must meet charging demands for a fully electrified personal vehicle fleet alongside the peaks in other demand for electricity, for example on the hottest days of the year. If unmitigated, the evening peaks in EV charging demand could require installing upwards of 20 per cent more power-generation capacity, the researchers say.
“Slow workplace charging can be preferable than faster charging
technologies for enabling a higher utilisation of midday solar resources,” Wei says.
Meanwhile, with delayed home charging, each EV charger could be accompanied by a simple app to estimate the time to begin its charging cycle so that it charges just before it is needed the next day.
Unlike other proposals that require centralized control of the charging cycle, such a system needs no inter-device communication of information and can be preprogrammed — and can accomplish a major shift in the demand on the grid caused by increasing EV penetration. The reason it works so well, Trancik says, is because of the natural variability in driving behaviours across individuals in a population.
By “home charging,” the researchers aren’t only referring to charging equipment in individual garages or parking areas. They say it’s essential to make charging stations available in on-street parking locations and in apartment building parking areas as well.
Trancik says the findings highlight the value of combining the two measures — workplace charging and delayed home charging — to reduce peak electricity demand, store solar energy, and conveniently meet drivers’ charging needs on all days.
As the team showed in earlier research, home charging can be a particularly effective component of a strategic package of charging locations; workplace charging, they have found, is not a good substitute for home charging for meeting drivers’ needs on all days.
Delayed home charging could make a surprising amount of difference, the team found. “It’s basically incentivizing people to begin charging later. This can be something that is preprogrammed into your chargers. You incentivize people to delay the onset of charging by a bit so that not everyone is charging at the same time, and that smooths out the peak.”