Fueling Capacity of Charging Stations

You might want to contact the manufacturer of the charging station or the product spec sheets to find out the charging capacity per station and just enter that info into the template. The credit compliance is primarily based on the number of charging stations, not the exact charging capacity. I believe that info is requested just to demonstrate it's an adequate charger for a typical installation, and to identify the model, not to require any calculations on how much you're actually recharging per car.

Since 3% of your parking capacity is 2 stations, you'll probably need to provide two separate stations instead of the one you mention (I'm assuming one station connects to one car). It's likely the credit is assuming one car would be plugged into each station for the duration of a typical business day, but since that assumption is not stated or examined further I doubt it's all that important as long as you have two stations.

Michelle - I understand your question a little better now. My assumption is the "Vehicle Fueling Capacity per Station (8 hr day)" is filled out based on how many cars can be plugged into the station at a time and recharged over an 8 hour day. So your one station could possibly work if it has the ability to recharge 2 cars at time, since you need two charging "spots." Would be worth finding out the cost difference between a one-plugger and a two-plugger.

I smell a CIR - or at least an inquiry to GBCI - since it's not entirely clear how that field of the table should be filled out given the range of different chargers available. For example, would one quick charger be enough to cover your needs since you have many short term visitors? How does the length of charge time affect how that form gets filled out?

If the project will only fund one charger that can charge one car at a time, you might consider Option 1, Preferred Parking... or a CIR to see if you can combine one charger with preferred parking. Hope that helps!

I had the same questions raised by Michelle regarding how to determine the vehicle service capacity of an EV charging station over an 8-hour period. I submitted an inquiry to GBCI and received the following response. Inquiry and response are copied below , but unfortunately the issues haven't been clarified for me.

Does anyone have experience/information to share on these issues?

Inquiry:
Our NC Retail project plans for 352 parking spaces. According to the rating system, the requirement for this path is to ”install alternative-fuel refueling stations for 3% of the total vehicle parking capacity of the site.” According to the sample credit template, the calculation of this percentage accounts for the “capacity per station [number of vehicles serviced per day], based on an 8-hour day” in addition to the number of stations installed. Therefore, (if we understand correctly) the charging stations included on our project must be able to service at least 352 x 3% = 11 vehicles during an 8-hour period.

We are unclear on how to determine the appropriate ‘capacity per station’ value for an electric charging station. In addition to the station’s charging rate, other variables affect the number of vehicles that may be serviced per 8-hour day, including:

1. the battery capacities of the vehicles being charged (as examples, at 240V the Nissan Leaf requires ~7 hours to charge fully, while the Chevrolet Volt requires ~4 hours – according to vehicle manufacturers);

2. the charge levels of these vehicles prior to beginning the charging process (most vehicles will not arrive to the charging station with zero charge);

3. the length of time that users spend at the supermarket (customers who charge their electric vehicles while at the supermarket are likely to charge their vehicles only until they are finished shopping, rather than waiting until their vehicles have been completely charged).

To consider extreme cases, a level II charging station could service 8/7=1.14 fully depleted Nissan Leaf vehicles in 8 hours, so 11/1.14=10 charging stations would be required to achieve the minimum threshold of 11 vehicles. On the other hand, the same charging station could service (i.e. partially charge) electric vehicles for 8 customers who each shopped for an hour (and charged their electric vehicles while they shopped). In this scenario only 2 charging stations would be required to achieve the 11-vehicle threshold. Please advise on how we should determine the appropriate value for ‘capacity per station.’

Response:
We believe the intent of the credit expressed in the LEED Online form is how many cars could be fully charged in one 8 hour "shift". For example if a building was open 24 hours the charging station could not be considered as having a capacity of 3 based on there being 3, 8 hour shifts in a day.

Please note that in this forum we cannot approve project teams strategies, only offer guidance. We highly recommend that before you submit this credit for review you submit a CIR describing your strategy to see if it would be accepted by the review team.

This is what frustrates me about this requirement to show 'capacity' without taking into account the typical use based on project type.

An electric car charging station will have different uses based on the type of visitor--office different than quick serve restaurant, etc. This also includes a different type of 'charge' per user--whether it be an electric car charging commuter to work, or a 'top off' situation at a quick serve restaurant.

Should you base the calculations on a 4 hour full charge, or an 8 hour full charge? Very vague.

We have also received a similar comment regarding EV charging station capacity, yet there appears to be zero guidance from the GBCI/USGBC, either in the reference guide or the credit interpretation database, as to how these are to be calculated. We propose the following methodology based on the information we were able to locate and the information provided by users here.

Based on some quick research seems like there are three relatively standard capacities for EV stations: Level 1, Level 2, and DC Fast Charge: http://www.afdc.energy.gov/fuels/electricity_infrastructure.html

From the AFDC website:
"Level 1: 2 to 5 miles of range per hour of charging
Level 2: 10 to 20 miles of range per hour of charging
DC Fast Charging: 60 to 80 miles of range in 20 minutes of charging" [or 180 to 240 miles of range in an hour]

Taking the middle range of each of these (Level 1 = 3.5 miles per hour, Level 2 = 15 miles per hour, and DC Fast Charging = 210 miles per hour), we can convert this into charges per hours using the Level 2 standard and the Nissan Leaf reported charge time of 7 hours per full charge Level 2 charger reported here: http://www.edmunds.com/car-technology/electric-car-battery-basics-capaci...

in this manner, 15 miles/hour = 7 hours/full charge
As a result, a single 8-hour full charge capacity is equivalent to 15 / (8/7) = 13.125 miles/hour.

This results in the following charging capacities based on charging type:
Level 1: 3.5 / 13.125 = .267 cars per shift
Level 2: 15 / 13.125 = 1.142 cars per shift
DC Fast Charge: 210 / 13.125 = 16.000 cars per shift

We have installed 2 units for a project that meet Level 2 charging (Schneider EVlink 240V 30Amp), and based on the discussion above and the information on the AFDC website I just linked to, I'm inclined to say our total capacity is 2.284 cars/shift.

I noticed messing around with the credit form, the way they're calculating compliance does not appear to be based on the number of stations alone, but the number of stations * the capacity per station, meaning a single DC Fast Charge station could theoretically handle a parking lot of 500 spaces with a capacity of 16/shift! Alternatively, it would take 57 spaces if a Level 1 charger was being used. This does not seem right at all considering it's highly unlikely that someone using a fast charge station at an office complex would be considerate enough to move their car once their charge is up, but that is how the credit template appears to work. I've also noticed the v4 form does not work with fractions, so it's unclear this is their intent. I've saved a filled out sample form here: https://dl.dropbox.com/u/343535/ssc4.3_dya.pdf

Alternatively, it could be that we're vastly overthinking this, as we have a single station with two plugs, meaning that it could just be they're requesting the number of outlets available per station, but then why would the 8 hour shift matter?

Here is what we received back from Schneider regarding the charging station in hand. We're assuming a 1.14 daily vehicle charging capacity based on a 7 hour charge:

"Our Level 2 EV Charging Stations are Input Power Rated 208-240 Vac, 30A, 1-Phase, 60 Hz., 7.2 kW Max.
This will require the use of a 2-Pole, 40A Circuit Breaker, and #8 AWG Copper Wire to protect and feed each of these units.

The actual rate of charge is determined by the Electric Vehicle, not by the Charging Station. A typical charge from say 0% to 80% will take approximately 6 to 8 Hrs.

Let me know if you have additional questions about any of our EV Charging Stations.

Regards,
Tom
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Tom Holladay | Schneider Electric | North America | Senior Product Support Specialist - Distribution Equipment