Field testing plug-in hybrid electric vehicles with charge control technology in the Xcel Energy territory

Original publisher: Golden, CO : National Renewable Energy Laboratory, [2009] OCLC Number: (OCoLC)436171273 Subject: Electric vehicles -- Research. Excerpt: ... Increasing the total connected time could justify the use of vehicles as a demand side controllable load or even a reserve capacity if the vehicles were to have vehicle-to-grid power flow potential. Figure 7: Plugged-in Duration by Time of Day Segment Figure 7 slices the plugged in hours in a different way by looking at them in terms of four, six-hour time slots throughout a day. The top graph shows the results for a weekday and the bottom graph is a display of the weekend characteristics. During the weekdays, surprisingly, the time slot that seems to have the least number of plug-in hours was 6pm to midnight, suggesting that the vehicles may have been used more often, parked in areas without available outlets, or that the drivers chose to wait to plug in their vehicles. The weekend results were significantly different in that the mid day hours 6am to noon and noon to 6pm had very limited hours of connectivity. The main difference here is most likely a result of having work place charging available during the week and limited infrastructure availability in the places where the drivers traveled on the weekends. If there was a desire for utilities to use these resources as demand-side load management programs or for ancillary services there is likely a need to explore public infrastructure opportunities such that vehicle connectivity can be ensured during all time slots and locations. Regarding ancillary service potential, the capacity of the vehicle to provide charge or discharge power was assessed. Figure 8 provides one week of measured field data for three of the test 11