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EV Growth Can Pose Challenges for Utility Transformers

Getty Images / PETOVARGA
Getty Images / PETOVARGA
Published On
Nov 16, 2021

The growth in plug-in electric vehicles (EVs) can put strain on nearby transformers, causing overloads, premature aging and potential failures. Fortunately, there is a solution: installation of battery energy storage systems (BESS), especially when paired with solar photovoltaic (PV) panels.

A 2020 study, “Economic Evaluation of Transformer Loss of Life Mitigation by Energy Storage and PV Generation” by Milad Soleimani and Mladen Kezunovic, finds that, due to decreasing prices, using BESS with PV is economically effective and mitigates distribution transformer loss of life.

Another study by Soleimani—“PV Generation, EV and Stationary Battery Optimal Control and Management in Distribution Grids”—analyzes strategies to mitigate transformer loss of life resulting from a high penetration of EVs.

The premise of this second study, “PV Generation, EV and Stationary Battery Optimal Control and Management in Distribution Grids,” was that accelerating adoption of EVs could cause some transformers to overload, leading to premature aging and potential failure, and thus adding expense for utilities and their customers.

Examining several scenarios, the study finds that in areas with high numbers of EVs, optimized use of a residential BESS, with or without PV panels, can mitigate transformer loss of life. Specifically, mitigation impacts of PV installations are negligible in some situations. Operating a BESS optimized for price only not only does not mitigate transformer loss of life, but can also sometimes negatively impact it.

The study notes that because of the high cost of PV panels, combining solar power with BESS, even when optimized, may not be economical without subsidies.

In the cases where the technologies provide a good return, utilities benefit. Therefore, according to Soleimani, “utilities should be investors.”

That can be done, he said, by “developing and providing rebates and other incentive programs to motivate consumers to deploy these resources.

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