Researchers at the MIT Energy Initiative have investigated the grid impacts of scaled up highway fast-charging (HFC) infrastructure by using an operations model of the 2033 Texas power grid with uniquely high spatial and temporal resolution.

Although highway fast-charging stations for electric vehicles (EVs) are needed to address range concerns, the characteristics of HFC electricity demand—its relative inflexibility, high power requirements, and spatial concentration—have the potential to adversely impact grid operations as HFC infrastructure expands.

In a paper published in the journal Energy Policy, Andrew Mowry and Dharik Mallapragada report that—in the reference EV penetration case corresponding to 3 million passenger EVs on the road—grid-HFC interactions increase system annual operational costs by 8%, or nearly $2 per MWh of load served.

Greater impacts are observed for higher EV penetration cases—up to $6/MWh.

Their analysis found that the majority of increased costs can be attributed to transmission congestion on feeder lines serving a minority of HFC stations.

Four-hour battery energy storage is shown to be more effective than demand flexibility as mitigation, due to the long duration of peak charging demand anticipated at HFC stations. Transmission network upgrades can also effectively mitigate grid-HFC interactions. Choosing the most effective mitigation strategy for each station requires a tailored approach.

—Mowry and Mallapragada

Resources

• Andrew M. Mowry, Dharik S. Mallapragada (2021) “Grid impacts of highway electric vehicle charging and role for mitigation via energy storage,” Energy Policy, Volume 157, doi: 10.1016/j.enpol.2021.112508