by josh perry, editor
[email protected]

a recent computer simulation run by the u.s. department of energy national renewable energy lab (nrel) has concluded that an increase in uncoordinated charging of plug-in electric vehicles will prove challenging for the electric grid and require a systems-level approach to vehicles, buildings, and the grid, according to a report from the nrel.

nrel engineer matteo muratori said his research points to key areas where additional investigation is warranted. (dennis schroeder/nrel)

“the simulation concluded that a pev market share of up to 3 percent, which translates to about 7.5 million vehicles, does not significantly impact the aggregate residential power demand,” the report explained. “more than 600,000 plug-in electric vehicles were already on the road at the end of 2016, a figure that includes about 150,000 sold during the year.”

the difficulty for the grid comes from geographic clustering. as a number of electric vehicle owners return home and begin charging, the grouping will “significantly” impact the peak demand and require enhancements to the electrical distribution network.

just as thermal management is a primary concern for the lifetime and performance of electrical infrastructure, such as transformers, power demands will also force systems to be designed to withstand greater workloads.

“earlier studies on how pevs might affect the grid assumed utilities would have some control over when charging occurs, referred to as coordinated charging, which will greatly facilitate pev integration,” according to the article.

future studies will look at consumer demands for low-power level 1 charging options or the more powerful, and faster, level 2 options. these studies will also need to focus on consumer behavior to determine the peak times for charging and whether or not that can be coordinated to have the least amount of impact on the grid.

the study was recently published in nature energy. the abstract of the report written by nrel engineer matteo muratori stated:

“electrification of transport offers opportunities to increase energy security, reduce carbon emissions, and improve local air quality. plug-in electric vehicles (pevs) are creating new connections between the transportation and electric sectors, and pev charging will create opportunities and challenges in a system of growing complexity.

“here, i use highly resolved models of residential power demand and pev use to assess the impact of uncoordinated in-home pev charging on residential power demand. while the increase in aggregate demand might be minimal even for high levels of pev adoption, uncoordinated pev charging could significantly change the shape of the aggregate residential demand, with impacts for electricity infrastructure, even at low adoption levels.

“clustering effects in vehicle adoption at the local level might lead to high pev concentrations even if overall adoption remains low, significantly increasing peak demand and requiring upgrades to the electricity distribution infrastructure. this effect is exacerbated when adopting higher in-home power charging.”