4 Questions to Consider When Planning EV Charging Infrastructure

 In EV Charging, EV Industry

One of the biggest stumbling blocks for organizations interested in adding plug-in vehicles to their fleet portfolio has been planning out EV charging infrastructure.

Calculating vehicle costs, fuel savings and suitability become all the more difficult when you don’t know where the cars are going to charge, how many stations will be needed, and how much they will cost to install.

Planning electric vehicle charging requires examining a number of factors, and often varies widely from one fleet to the next.

To help you get the process started, we spoke with the Andrea Pratt (Green Fleet Program Manager) from the City of Seattle, and Phillip Kobernick (Sustainability Project Manager) from Alameda County to learn about their experiences thus far.

In this article (part 1), we take a look at four key considerations when leading a successful fleet electrification program.

1) When will you be investing in electric vehicles?

Electric vehicle costs and capabilities are improving rapidly. While this is great for the overall outlook for plug-in adoption, it leads many potential buyers to adopt a “wait and see” approach. After long-term costs like fuel and maintenance were factored in, even expensive first-generation plug-in models had the potential to save fleets money. A half-decade later, the outlook has already improved considerably.

As attractive as future innovations and cost improvements may be, they shouldn’t serve as an excuse to delay investments that could be beneficial today.

First, figure out whether plug-ins meet your needs using data collected from existing vehicles. Use mileage to compare fuel costs. Analyze duty cycles to make sure range capabilities and charging periods are feasible.

Sample electric vehicle suitability report

Fleets can use telematics to understand where electric vehicles are best suited.

This also extends to charging infrastructure. Whether you’re installing your first charging station or considering expanding a pilot program to serve the needs of a full-scale plug-in fleet, the first step is determining how much of an investment to make and when. There are several factors to consider here:

  • Budget: How much money is available to spend now? What can be done to get more?
  • Available Incentives: A number of federal, state and local programs exist to help businesses with the upfront costs of installing charge stations. Familiarize yourself with the rules and application process. When are the deadlines? How much funding is left in the program?
  • Replacement Schedules: Most fleets have a predetermined window for replacing their vehicles, usually measured in miles or time of service. Many fleets choose to wait until the natural end of the service life of a vehicle before replacing it with a plug-in. Based on mileage and duty cycle requirements, some cars may also be better suited than others.

“A good time to invest was three years ago”

… says Phillip Kobernick, Sustainability Project Manager for the County of Alameda. Many government subsidies for charging infrastructure were launched a half-decade ago or earlier, and some have since run out of funding.

If deadlines and funding caps are approaching, there may be opportunities to save money by “overbuilding” charge infrastructure slightly ahead of a fleet’s replacement calendar.

2. Where will the stations best serve your needs?

Map of charging stations in SeattleIn 2009, the City of Seattle received a federal grant to install public and municipal fleet charge infrastructure under the American Recovery and Reinvestment Act. The initial deployment consisted of just 66 charging stations—20 public and 46 for fleet use—but has since grown to roughly 150 fleet chargers, most of which service both the general public and city vehicles.

As one of the early pioneers of municipal plug-in adoption, Seattle faced the challenge of crafting a scalable strategy for charger deployment without many test cases to learn from. Which locations would best serve the needs of the city’s expanding fleet of limited-range Nissan LEAF EVs?

“We went to where the cars were,” says Andrea Pratt, Seattle’s Green Fleet Program Manager. “Most [of the chargers] are at a main hub, the Seattle Municipal Tower. The rest are satellite installations at lots throughout the city.” Pratt and her colleagues prioritized installations at the various satellite locations based on vehicle replacement schedules, which told them where incoming EVs would be parked when not in use.

As one of the early municipal fleet plug-in adopters, Seattle wasn’t able to draw on fleet telematics data to inform these decisions. “We don’t have a telematics system” Pratt says, “but we realize it would have been very useful.”

3. How many charging stations will you need?

There’s no one-size-fits-all formula for determining how many charging stations a fleet will need. A number of considerations come into play, including:

  • The duty cycles of the vehicles at each site
  • The balance of plug-in hybrids vs all-electric vehicles
  • The capacity of the battery packs that will need to be charged
  • Whether the stations will be exclusively for fleet use or open to the public

In two and a half years, the County of Alameda, which encompasses twenty cities in the East San Francisco Bay Area, released 70 plug-ins into its public fleet. These vehicles were supported by 66 charging station installations over the same period, most located at a central hub in a downtown Oakland parking lot. The chargers are open to both government fleet vehicles and the general public.

Charging stations at a parking garageAlameda started with a low charger-to-vehicle ratio at its main downtown Oakland parking lot, but quickly found that demand for the stations—both public and fleet—outstripped the number installed. As the build-out progressed, the county added chargers to meet the needs of existing vehicles and give the EV fleet some room to grow.

Data is key to optimizing the number of charging stations to be deployed at each location. By determining the typical duty cycle of the cars parked at a site and how frequently they charge, fleet managers can predict how many plugs will be in use during peak charging periods.

This ensures that a fleet maximizes the electric mileage of each car and while constraining installation costs—two factors that are key to producing a positive initial ROI.

4. What kind of stations will you need?

Based on the manufacturer, electric vehicles employ three different charge standards—meaning not all plug-ins are compatible with all stations. American and European vehicles mostly follow the SAE Combo standard, while Japanese makes utilize CHAdeMO. Tesla has its own standard.

Most fleets aim to acquire vehicles that follow the same charge standard—but this isn’t always possible. Perhaps there are older vehicles left over from an early test-fleet, or maybe a fleet has procured a few Teslas for its executive motor pool?

In these cases, it’s important to distribute the right stations to the right locations to serve all of the vehicles that will be parked there. Most vehicles will charge exclusively from a central hub, but some may frequently parked between several lots. If your fleet utilizes plug-in hybrids with smaller battery packs, the ability to charge them in as many locations as possible maybe be crucial to maximizing their electric mileage.

Then there’s the question of charge speed. Level 1 charging—which is sometimes referred to as “trickle charge”—allows vehicles to charge using a standard 120-volt outlet, but it can take more than 20 hours to fully replenish the average EV. Level 2, which is by far the most commonly-used charge speed, ups the output to 240 volts. Level 3 is also known as DC fast-charging, and can bring a typical 100-mile EV to around 80 percent in just a half hour.

Battery size and duty cycle are crucial factors in choosing between Level 1, Level 2, and (vastly more expensive) Level 3 stations. Many small-battery plug-in hybrids may not necessarily benefit from a Level 2 station, while a small fleet of all-electrics that tend to be in use around the clock (like taxis,) may be best served by a single Level 3 station.

Sample electric vehicle suitability report

Telematics can help fleets understand what EV charging infrastructure is needed.

Making the Right Decision for Your Fleet

The most powerful advantage a fleet manager can have in answering these basic questions is knowing how her vehicles are used—not just in a general sense, but with as much specificity as possible. Telematics, whether collected from existing electric vehicles or from ICEs in advance of an investment in plug-ins, are the best way to collect that data.

Next week, we’ll look beyond these broad questions and examine some of the logistics of EVSE deployment:

  • What kinds of grants are available to help offset infrastructure costs?
  • How can fleets work with utilities to identify and minimize the cost of additional electrical capacity?
  • What are the essential factors in maximizing the ROI of EVSE investment?

We’ll return to Seattle and Alameda County to help answer those questions and more.

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