Recommendations for charging infrastructure in a new parking deck

[dsm363]

I was contacted by someone building a new parking structure in the downtown area of a relatively large city. He asked what I thought would be good to install there (given constraints that the cost goes up the more Amp service the structure needs). I thought I'd ask what others thought.

I believe he is looking to install 2 80A J1772 valet only accessed EVSEs and maybe a few level I J1772 EVSEs for monthly renters. I would prefer 32 or 40A J1772 EVSEs for monthly parkers. He asked how much would people be willing to pay for level I service on top of monthly parking fee and for level II EVSEs (depending on how many amps)?

I was thinking level I EVSEs would be fine for people parking plug-in hybrids like the Volt or Plug-in Prius overnight but likely not that useful for the Model S (but better than nothing as I don't think there are any parking decks in this particular area with EVSEs of any kind for monthly use).

 

[TexasEV]

Who will be parking in this garage? The answer will be different if it's mostly daytime parking for downtown office workers or shoppers, vs. overnight parking for a nearby hotel. Also is this a tourist destination or will parking be for locals?

 

[dsm363]

I imagine this would be for locals as parking is limited downtown and would be for monthly subscribers. Alot of condos and apartments have limited parking or don't allow charging to be done easily or cheaply so would work for them.

 

[richkae]

Does he have a total power budget?
How many EVSEs can he put in? Does it have to add up to a fixed number of kW ( say 40kW - Is it a choice between 2 20kW units or 7 6kW units? )

When you say monthly parkers are you thinking office workers who are parking there during the day or condo residents that are parking there as their residence ( overnight )?

A plug in prius has what a 4 kWh battery? If so, plugging in your PiP every night would let you drive as a pure EV about 12 miles per day? That's about 1/4 of a gallon of gas - about $1 worth. So $30 per month would be a maximum that a PiP owner would be willing to pay. If you only drive 2/3 of the days - its only $20.
A Volt could save 38 miles per day, but realistically wouldn't drive every day or the max amount every day ( has to average less than 12000 miles per year ). So about $100 per month savings. If it were me, I would be willing to pay the $100 to be fully charged every night if the alternative was no charging - but other owners would probably likely put the threshold slightly lower ( why would you buy a Volt and give up all the savings? ). The Volt would probably just barely be fine with the 1.6kW from level 1.
A pure EV owner does a completely different calculation and has a lower threshold for what they are willing to pay. The question for them is how much more are you willing to pay for the electricity than it actually costs. Driving 1000 miles per month is about 300 - 350kWh for a pure EV owner. At 10c per kWh, that's $30-$35 per month. Anything more than a 50% premium on top of that would be hard to stomach I think.

So the answer on how much someone would be willing to pay for the ability to charge overnight at their residence is somewhere in the $20 to $100 range ( on top of the parking fee and including the energy cost ). That also assumes that you get the EVSE in your dedicated spot. I wouldn't pay extra per month unless I have guaranteed access to the charging.

I think that day parking office workers would be willing to pay near ZERO extra on top of the energy cost to plug in during the day. There are several Leafs, Volts and Model S in my office building. ( At least 3 Leafs, 2 Volts, 4 Model S, and 1 Roadster - probably more ) There are also 3 chargepoint 6kW EVSEs that bill $1 per hour - which works out to at least 16c a kW and usually a lot more unless you immediately move your car when done charging - that part is key. They never get used. Anyone who has an EV can drive to and from work without needing a charge, so isn't willing to pay a premium for their electricity - and have to move the car during the day to avoid getting gouged.

 

[dsm363]

Does he have a total power budget?
How many EVSEs can he put in? Does it have to add up to a fixed number of kW ( say 40kW - Is it a choice between 2 20kW units or 7 6kW units? )

Thanks, I'll ask. I've been vague as I just sent him an e-mail with those questions and asking if I can post which city as that would be helpful but thought the vague advice would apply to any large city with limited parking.

 

[Dave EV]

richkae has all the right questions.

L1 (120V / 12-16A) - Very useful for PHEVs, long term parking. These can be simple GFCI outlets - if you install an EVSE you might as well go for 20A unless it's not in your power budget.

L2 (240V / 16-80A) - 30A is your standard and gives a good rate of charge. Only Teslas and RAV4-EVs can charge faster, which limits the usability of higher current units. Unless you're on a power budget you probably want to install 30A units.

If you're looking to install a variety of stations, with varying rates, you could probably do something like this from basic to premium (overkill):

L1 - 120V 20A outlets (120V, 12-16A typical)
L2 - 240V 16A EVSE - covers most EVs on the road
L2 - 240V 30A EVSE - allows faster charging for those that want/need it
L2 - 240V 40A EVSE - Tesla / RAV4-EV owners
L2 - 240V 70A EVSE - Tesla owners w/dual chargers

For most I think the 70A option is overkill - that rate of charging is rarely needed and the fewest number of cars can use it. Still, it can be very useful when you do need it!

To make it simple, you could keep it simple with 2 options:

L1 - 120V 20A outlet
L2 - 240V 30A EVSE

Will you be billing for energy used as well? Not hard to install inexpensive dial meters (google for Hialeah Meters). Bill a flat rate for access to the outlet/EVSE + energy cost.

 

[richkae]

Just to beat the dead horse a little more...
The biggest thing killing my use of opportunistic charging is paying $1 per hour regardless of how much energy I use. It is a total catch-22 because I am a huge advocate of paying for the space - not the electrons - as a way to keep the spots from being ICEd. When I need a charge, I am perfectly happy to overpay, but when I am just opportunistically plugging in I do not - therefore I always charge at home and never at work.

 

[dsm363]

Will you be billing for energy used as well? Not hard to install inexpensive dial meters (google for Hialeah Meters). Bill a flat rate for access to the outlet/EVSE + energy cost.

Thanks. I actually don't have anything to do with this project other than someone was looking to build a new parking deck and asked for advice on what people with EVs would want, what would attract business and what people would be willing to pay. I think keeping it simple would be great as well. I had suggested as many L1 120V outlets as possible or at least conduits that wire can be pulled through in the future as digging up concrete after the structure is built must be much more expensive than getting the infrastructure or wiring done ahead of time.

 

[VolkerP]

would underline what richkae and drees said.

In addition, ask the project head to consider energy efficient lighting (LED etc). The lights are mostly on 24/7 in a parking structure. He can save many kW of electrical power demand this way, thus freeing up electric demand for EV charging.

If the spots are rented, I suggest to offer a mix of slots, some eqipped with 110V sockets, some with L2 EVSEs at 30Amps. People will actually chose the charging solution that best fits their needs, if there is a monetary incentive to do so.

The conduit should have excess capacity to upgrade the wiring later.

If a big number of parking slots with high power charging (>40A) is requested, he should look in smart EVSEs that can balance the electric demand to not overdraw on the supply lines.

 

[dsm363]

Thanks. I'll pass that along. I found this too which might be useful for them.


CBEA High-Efficiency Parking Structure Lighting Specification

Linked PDF:
http://apps1.eere.energy.gov/buildings/publications/pdfs/alliances/parking_strucutre_light_factsheet.pdf