Presented by Tom Saxton at Plug-in America during Drive Oregon's Workplace Charging Workshop in April 2015

1. WORKPLACE CHARGING
THE GOLDILOCKS APPROACH
Tom Saxton
Chief Science Officer, Plug In America

2. WORKPLACE CHARGING
GOALS
Increase awareness and adoption of PEVs
Enable PEV use for those who can't charge at home
Increase useful electric range
Minimize company cost
Plan for a future where nearly everyone drives electric
and up to 60% need charging at work

3. FREE CHARGING
Best for raising awareness and adoption of PEVs
The Choice: ubiquitous charging or oversubscription
Oversubscribed charging is unreliable
Only useful to drivers who don't depend on it
WORSE than no charging for those who need it

4. EXPENSIVE CHARGING
Twice, or more, than the cost of electricity
Fine for occasional use
I happily pay $0.49/kWh (5x) when I need it
Not economically viable for daily charging
Need to stay well below cost of gas

5. THE “JUST RIGHT” FEE
A little over the cost of overnight home charging
Discourages use by those who can charge at home
Cost effective for those who can't charge at home
Average residential cost in Oregon is 10.5 cents/kWh
“Just Right” Target: 12 to 15 cents per kWh

6. EQUIPMENT OPTIONS
Level 1
Outlets
Stations Primary choice for workplace charging
Level 2 Charging Stations
3.6 kW, 7 kW, up to 19.2 kW
Can be networked
DC Quick Charge Stations

7. LEVEL 2 CHARGING IS
TOO FAST
Most drivers commute less than 40 miles roundtrip
Level 2 (7 kW) can replenish 40 miles in about 2 hours
Can charge multiple vehicles per day
Swapping cars for charging
Distraction for employees
Reduces available parking in full lots

8. LEVEL 2 UTILITY ISSUES
Plentiful Level 2 charging may:
Increase demand charges
Lower time-of-use billing
Impact varies with local utility rate structure

9. LEVEL 2 BILLING ISSUES
Billing by kWh seems the most fair, but doesn't bill
for the scarce resource: availability of charging
Level 2 billing by time is unfair because some
vehicles charge faster than others (many vehicles
limited to 3.3 kW)
Billing by session is the worst of all: unfair and
encourages long charge sessions

10. NETWORKED CHARGING
STATIONS
Offer many services in addition to billing: access
control, use analysis, service alerts, etc.
Equipment is expensive ($3,000 or more vs. $500)
Cost of billing may double the cost for the company to
break even
Billing at twice the cost of electricity is too expensive
for daily use

11. BASELINE SOLUTION
Level 1 Charging Stations
Equipment cost about the same as simple Level 2
Will add 30+ miles of charge in 8 hours
Bill by month assuming 8 hours of charging per day
Access control by parking pass

12. ONE SIZE DOES NOT FIT
ALL
3.6 kW Level 2 billed by month
7 kW Level 2 for occasional use, billed by time and
energy
DC Quick Charge may be appropriate for large
companies, billed appropriately

13. TOM SAXTON
http://www.pluginamerica.org/drivers-seat/workplace-charging-goldilocks-
approach
tsaxton@pluginamerica.org