[wesley]

I realize the discussions here center around North America, but as a foreign national I'd like to provide some outside perspectives.

In Korea, there are three levels of public charging stations:

- 100kW (500V 200A) DCFC (CCS)
- 50kW (400V 125A) DC/AC FC (CCS, CHAdeMO, 3-Phase AC)
- 7kW (220V 32A) Level 2 AC

100kW stations have started to appear this year and is currently dozens of them. There are more than 2,500 50kW chargers and 4,000 7kW chargers throughout the country.

Originally, the cost of charging was set to be KRW313/kWh (US$0.28) regardless of speed, for the chargers installed by the government, which make up the majority. However, this was lowered to KRW173.8/kWh (US$0.16) temporarily for 3 years, from 2017 to 2019.

Chargers installed by private and public companies have adjusted their pricing when the discount pricing was set. Many of them have matched the government pricing, while some others like Posco ICT decided to keep it a bit higher at KRW250/kWh (US$0.22). One private company that is currently pushing a lot of 100kW stations recently (S-Traffic), use this pricing for the 100kW chargers, while the 50kW chargers cost KRW173/kWh.

Meanwhile, there are credit cards that offer a discount of 30 to 50% on the charging costs, which means that the final cost to the user may be as low as KRW86.9/kWh (US$0.08). In order to take advantage of this, you need to enroll in the charger network membership (free to register, no monthly fees) and register the eligible credit card into your payment profile.

As for the session time-outs, the government chargers have a 40-minute timer while the private ones generally lack one. Fees associated with using a charger is included in the per-kWh pricing, therefore you do not get charged extra.

 

[Dimitrij]

Where I live/drive, the cost of DCFC charging is never a linear function of the kWh's - the payment schemes remind me of the 1990's cell phone plans.

One L2 charger I regularly use, though, is $0.11/kWh dispensed, which translates into $0.12 or so received on the car's end. Another L2 charger I use is something like $0.18/kWh received.

 

[quirkySquirt]

That's a pretty simple system: charge based on your consumption. I do wonder, though, if perhaps they could increase the DCFC kWh cost to reflect the convenience of faster charging. None of this charging by the minute nonsense in the US with connection fees. I recall the reason for the time-based charging in the US is due to some law that only power companies can charge by the kWh. Weird rule.

 

[NewsCoulomb]

Part of the complication in the United States is that some regions restrict selling power to public utilities, so even if at station owner wanted to put a set rate based only on consumption, they might not be allowed to.

 

[wesley]

That's a pretty simple system: charge based on your consumption. I do wonder, though, if perhaps they could increase the DCFC kWh cost to reflect the convenience of faster charging. None of this charging by the minute nonsense in the US with connection fees. I recall the reason for the time-based charging in the US is due to some law that only power companies can charge by the kWh. Weird rule.

Part of the complication in the United States is that some regions restrict selling power to public utilities, so even if at station owner wanted to put a set rate based only on consumption, they might not be allowed to.

That's interesting to know. In Korea, there is currently only one company that is lawfully classified as an electricity retailer - KEPCO. So traditionally, no other company would be allowed to do EV charging business, let alone a time-based charging. Technically, other companies could be licensed as a retailer as well, but some complicated issues make this infeasible at the moment.

Obviously, this wasn't going to work, so the governing law (specifically, the Electricity Utility Act) was revised to add a classification called "New Electricity Utility", which includes EV charging business and small-scale electricity trader. An EV charging business can set its own rate for charging and all of them have opted to use the per-kWh pricing.

There has been an announcement today that the EV charging membership card issued by the Ministry of Environment will work with the chargers operated by nine major companies at a flat rate of KRW173.8/kWh starting next Monday, pretty much eliminating the need for applying individual memberships.

 

[raitchison]

Interesting stuff, IMO the biggest reason to adopt per-minute pricing over per-kWh pricing for DCFC is that per-minute pricing effectively penalizes people who would "top off" their cars (charge from ~70%-~100%) with DCFC which would be very time inefficient due to the nature of how DCFC works. In effect these people will pay less to monopolize the charger.

 

[discodanman45]

Interesting stuff, IMO the biggest reason to adopt per-minute pricing over per-kWh pricing for DCFC is that per-minute pricing effectively penalizes people who would "top off" their cars (charge from ~70%-~100%) with DCFC which would be very time inefficient due to the nature of how DCFC works. In effect these people will pay less to monopolize the charger.

I think I may be one of the few people that probably think the pay per minute is the best approach. Keeping more chargers available is very important for travel. Topping off a battery with charging by kWh would make more people use the chargers and not be the most efficient use of them. No one should be using a fast charger if they are going above 80% charge. The are made to take a battery up to 75% capacity quickly and then get back on the road.

 

[quirkySquirt]

Hmmm, I forgot about the top-off charging behavior. Good point, @discodanman45 and @raitchison. I think an ideal would be a per/kWh charge blended with a per-minute or consumption rate charge.