Electric vehicle integration: 6 best practices for utilities

Electric vehicles—are they something utilities should even care about? 

Southern California Edison (SCE) certainly does. The utility recently announced it's preparing itself for the integration projected 350,000 electric vehicles (EV) into its service territory by 2020. SCE studied 12,000 early EV adopters currently in its territory and released a report, “Charged Up: Southern California Edison’s Key Learnings about Electric Vehicles, Customers and Grid Reliability," detailing the best practices it has developed on the road towards EV grid integration.

Here is what utilities need to know:


SCE's report found that grid infrastructure needs to be upgraded to meet EV-owning customer's needs and support EV integration:

  • Since "PEVs can draw as much as another household’s electricity load," SCE "integrated the expected load from PEVs into its standards" for circuit sizing.
  • Only 1% of SCE's transformer upgrades since 2010 have been due to plug-in electric vehicles (PEVs). 
  • ​SCE upgraded "as needed," whenever they were notified about a new EV charging station.
  • Anytime SCE replaced a transformer for other, non-PEV-related reasons, they made sure it met new sizing standards to allow for PEV load.


SCE's study revealed several important data points that have mitigated the impact of EV grid integration thus far:

  • "Current data shows that about 50 percent of [plug-in hybrid electric vehicle (PHEV)] drivers charge at Level I (120 volts), so we’re seeing a much lower impact on our grid distribution circuits than if more customers charged at the higher Level 2 (240 volts)."
  • "Current driving patterns combined with PEV features also seem to minimize the impact of PEV charging. Studies show that about 70 percent of PEV owners commute 40 miles or less daily. Most BEVs can travel at least 60-80 miles of all-electric range on a full charge and PHEVs will generally run 20-40 miles all-electric range on a full charge before going into hybrid mode. As a result, many PEV owners can fuel at night at home and fully recharge their battery during off-peak hours at Level 1. That means low impact on the grid, low installation costs and the lowest electricity costs if customers are on a time-of-use rate."

SCE noted that a rise in market share for battery electric vehicles (BEVs) could "create new implications for grid reliability" as BEVs "come with on-board chargers with higher capabilities (from 3.3 kilowatts to 6.6 kilowatts or even higher)."


SCE realized that off-peak charging largely mitigates the impact of EVs on the grid. EVs' programmable end- or start-time charging feature helps customers charge their EVs when it's best for them and the grid: 

Setting an end time creates a more random start time pattern because batteries have different “states of discharge” and charge at different levels, thus requiring various amounts of electricity. When customers set an “end charge” time for charging to be complete, they randomize the start time of their charging, which prevents a large number of vehicles from coming online at the same time – avoiding power-load spikes that potentially could affect the local distribution system.

The utility found that time-of-use "rate plans are encouraging off-peak charging behavior as designed." 


Customer engagement drives customer satisfaction. SCE knows this: the utility set up a website to educate consumers on EVs and help them make informed decisions based on "significant cost implications, including metering arrangements, rates, charging equipment and installation." The site includes a Plug-In Car Rate Assistant app to estimate the costs of charging EVs for customers. The utility employed "geo-targeted search engine marketing" to target online searches for EVs in their service area by neighborhood—safe to say, early EV adopters typically live in more up-scale neighborhoods, making this a "cost-effective" approach. Through these resources and more (for example, social media), SCE prompts EV adopters to speak with a utility representative to assist with integration on both the customer and utility side. 

Opening these lines of communication with customers is good for both PR and customer satisfaction, but it also helps the utility. SCE and other utilities are not yet fully prepared to integrate EVs into the grid and, while this report suggests it will not be a massive strain on the grid or utility, engaging with early adopters' needs will smooth the process going forward. 


After frustration over a 2008 BMW EV pilot in SCE service territory, SCE learned that it need to coordinate with stakeholders, including cities. Here's what it did:

In 2010 and 2011, we re-engineered our processes and began collaborating closely with the cities in our service territory, sharing best PEV practices and supporting their improvement efforts. Today, the entire process of switching rates, upgrading infrastructure, permitting and inspection averages four to five days.

SCE realized that communication with key stakeholders (in this case, cities) was essential to successful EV grid integration. SCE's report further elaborates on how cities can help through these five actions:

1. Implementing process streamlining for [electric vehicle supply equipment] infrastructure installation
2. Implementing public education and outreach programs
3. Actively participating in regional PEV readiness initiatives
​4. Implementing PEV infrastructure
5. Amending building codes for PEV charging​



According to the report, utilities and other stakeholders (for example, large-scale apartment complexes) need to address these key considerations when pursuing EV integration:

  • Dedicated charging stations in assigned parking spaces vs. community stations that benefit all residents.
  • Decisions on who carries the costs of charging equipment, installation and ongoing maintenance, which may include costly electric panel and circuit upgrades.
  • Inaccessibility to electricity in parking spaces.
  • Costs and payments for charging when the charging station is not connected to an individual customer meter.

DIVE INSIGHT: More than ever, utilities need to consider how they will approach EVs and grid integration, whether they want to be involved and to what extent. As the traditional one-way energy value chain gets disrupted and customers gain increased access to valuable energy assets, utilities must redefine their own value in this reshaped landscape.

Utilities are primed to innovate their business models and EVs represent a potential avenue of opportunity, even if the value of EVs for utilities is not yet completely clear. First movers like SCE will show other utilities the potential opportunities and pitfalls on the road towards integration. SCE has taken the first step—but what will other utilities do? Buckle your seatbelts, folks...


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Filed Under: Transmission & Distribution Technology
Top image credit: Steven Depolo