Telefonix L1 PowerPost
A very interesting article on workplace charging appeared over at Plug In America.
The first part on costs of charging correctly points out that workplace charging shouldn't be free for two major reasons.
First is that many people would like to charge for free and station usage will be high, sometimes preventing those who really need to charge, as the spot will be busy because someone that doesn't need to charge to get back home is just enjoying free energy.
The second problem is that to get as much free energy as workplace charging offers, EV drivers will shift charging from night off-peak time at home to the on-peak time during the day.
According to Plug In America, the right way is to bill charging just a little above the local home rates so those who need it will pay a little more for extending daily range:
"The solution is to provide charging billed at just a little above local home rates. This extends the economic advantages of driving electric to those who cannot charge at home. It also eliminates the incentive to shift charging from home to work, reducing the number of stations needed to satisfy demand. Together these benefits minimize the infrastructure cost of providing charging at work and focus the benefits on those who need it the most."
How about the type of charging station to choose? Level 1, 2 or maybe a DC fast charger?
Here the answer is Level 1 or sometimes Level 2. Level 1 is the king as the workday is long enough to replenish range for most commuters. Billing can be simple because all electric cars, regardless of on-board charger, can utilize all the available power and the employer can set a fixed monthly rate. Total cost of installation is similar to simple outlets (NEMA 5-15 or NEMA 5-20), but you get a J1772 plug and and don't need to the open trunk for the EVSE cord.
Level 2 would be good, but most times it will charge cars in the first half of the day (higher power used all at once can be a problem) and the rest of the time it will be wasted or if there are not enough stations, employees will be distracted by shuffling cars.
It would be good to have some 3.6 kW Level 2 available for a premium fixed monthly rate for those employees that utilize and need higher power. Higher power 7 kW stations should be available at higher prices to use occasionally too.
DC fast chargers are a good solution only for large companies with a large number of EVs around.
Generally speaking, workplace charging should consist of mostly Level 1 charging, billed at just above the cost of 8 hours of charging per day, with some Level 2 available at a higher billing rate. Even though Level 1 charging stations and installation may not be any less expensive than non-billing Level 2 stations, this will meet the goal of increasing EV adoption and use while minimizing infrastructure costs, utility demand charges, and lost employee time."
Source: Plug In America