WetEV
Well-known member
or battery storageSageBrush said:
Demand Charges, storage costs and Public DCQC
- Thread starter WetEV
- Start date
Help Support My Nissan Leaf Forum:
GetOffYourGas
Well-known member
Yes, battery storage would certainly be better, but at a cost. Each site operator would have to make the call whether it is worth adding that cost in order to provide a higher charge rate. Keep in mind that ultimately it is the consumer who pays the premium.
Until batteries are much cheaper (or the market is awash with used EV batteries), I suspect that on-site storage will continue to be the exception rather than the rule.
Until batteries are much cheaper (or the market is awash with used EV batteries), I suspect that on-site storage will continue to be the exception rather than the rule.
WetEV
Well-known member
Battery storage reduces demand charges. The savings are fairly drastic at low utilization sites.GetOffYourGas said:
Suppose there is a site that right now has one car per month average. 150kW car, demand charge is most of the electric bill of $1,998.25 per month.
An alternative design for the site might have 50kWh of storage at $600 per kWh would cost about $30,000 more to install, but could use the "small demand rate" and have $0 in demand charges. Breakeven would be in less than 2 years. $300 per kWh installed might be achievable today, and would be fairly soon.
Another alternative is 50kW maximum for the site.
Such a site would never be profitable, much as rural highways, telephone, postal and electric are subsidized by the cities, so would remote location charging. How this is done remains to be determined: by a profit maximizing monopoly, by a tax on charging with the proceeds going to subsidize low utilization locations, or a coverage area mandate, or direct government funding. In any case, would be some sort of political and economic process to determine what the network coverage was.
WetEV
Well-known member
Traffic patterns are going to vary by site. A successful network will have sites that are profitable and sites that are not.
Start with one location, say this one:
https://www.wsdot.wa.gov/Traffic/API/PermanentTrafficRecorder/?siteId=R019S&tables=TrafficVolumeByHour&startYear=2019&startMonth=1&endYear=2019&endMonth=12
This is I-5 between Seattle and Portland. While not all traffic is non-local, a fairly high percentage is. While not every car would need a recharge on a trip from Seattle to Portland, at 173 miles , the fraction would depend on the battery size/range. Expect a distribution, as there would be some cars with "city range" doing a longer trip, and some longer ranged cars. Actual trip miles would vary as few would be traveling from city center to city center.
Actual recharging locations would also vary with battery size. With a 500 mile or more range BEV, this might be a no public charging or recharge at home only trip. With a 250 mile range, destination charging might be a large fraction of the Seattle to Portland traffic, assuming hotels generally have that. If not, then recharge close to destination city would likely make sense. Smaller battery EVs might need a recharge somewhere around here. Charging speed curve also impacts this.
Site battery storage makes sense on the daily cycle, as the peak hour to average is about 2.5 to 1. I'd expect this to vary by site, of course.
Any storage on longer than daily is less useful, as the peak day to average at peak hour is about 1.4:1. Maybe a little for weekends vs weekdays.
Number of chargers needed depends on lots of factors, ranging from battery size to actual trip sources and destinations, of which this data isn't fully able to resolve.
I am interested in doing a more complete analysis traffic patterns of this and other sites.
An interesting map might be the likely cost of charging at a range of sites. To make it useful, ranges of likely distributions of parameters is needed.
Start with one location, say this one:
https://www.wsdot.wa.gov/Traffic/API/PermanentTrafficRecorder/?siteId=R019S&tables=TrafficVolumeByHour&startYear=2019&startMonth=1&endYear=2019&endMonth=12
This is I-5 between Seattle and Portland. While not all traffic is non-local, a fairly high percentage is. While not every car would need a recharge on a trip from Seattle to Portland, at 173 miles , the fraction would depend on the battery size/range. Expect a distribution, as there would be some cars with "city range" doing a longer trip, and some longer ranged cars. Actual trip miles would vary as few would be traveling from city center to city center.
Actual recharging locations would also vary with battery size. With a 500 mile or more range BEV, this might be a no public charging or recharge at home only trip. With a 250 mile range, destination charging might be a large fraction of the Seattle to Portland traffic, assuming hotels generally have that. If not, then recharge close to destination city would likely make sense. Smaller battery EVs might need a recharge somewhere around here. Charging speed curve also impacts this.
Site battery storage makes sense on the daily cycle, as the peak hour to average is about 2.5 to 1. I'd expect this to vary by site, of course.
Any storage on longer than daily is less useful, as the peak day to average at peak hour is about 1.4:1. Maybe a little for weekends vs weekdays.
Number of chargers needed depends on lots of factors, ranging from battery size to actual trip sources and destinations, of which this data isn't fully able to resolve.
I am interested in doing a more complete analysis traffic patterns of this and other sites.
An interesting map might be the likely cost of charging at a range of sites. To make it useful, ranges of likely distributions of parameters is needed.
knightmb
Well-known member
Has this been asked? Why not have multiple lines of "50 kW" service to the same location to get the discount and then just combine them for charging since it will be DC and DC can be combined unlike AC which requires expensive equipment to get the waveforms in sync?
