WORKPLACE CHARGING THE GOLDILOCKS APPROACH

Tom Saxton Chief Science Officer, Plug In America

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

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

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

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

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

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

LEVEL 2 UTILITY ISSUES

Plentiful Level 2 charging may:

Increase demand charges

Lower time-of-use billing

Impact varies with local utility rate structure

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

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

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

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

TOM SAXTONhttp://www.pluginamerica.org/drivers-seat/workplace-charging-goldilocks-

approach tsaxton@pluginamerica.org