Large-scale real-life trials using 70 Plug-in Hybrid Vehicles in France began in the Spring of 2010. And in May of 2011, at the first anniversary, a presentation was held in Strasbourg for PHV users. This is an account of that event.
The nearly 70 users who gathered at the City Hall listened intently to the presentation given by the French power company, EDF, and Toyota Motor Corporation that are in charge of the trials.
In the reports summarizing the user feedback, 70% responded that they were "satisfied with the fuel consumption of the Prius PHV" and 80% said that they had "naturally become ecologically conscious". It was found that when driving an eco-vehicle, an increased awareness of the ecology naturally occurred.
Improved fuel efficiency through increase in charge frequency is a feature of the PHV. (see diagram,above). Users who charged their vehicles twice a day saved 62% in fuel costs over gasoline powered vehicles of the same class. (see diagram, right)
note: In Europe, fuel consumption is expressed in the quantity of fuel required to travel 100km. In the graph, therefore, the smaller number indicates better fuel efficiency.
On the other hand, it was also found that approximately 30% of the users only charged their vehicles once in from 2 to 10 days. When not charged, the Prius PHV becomes a "conventional Prius". Because it is based on a hybrid vehicle, unlike an electric vehicle, it is possible to drive it even without charged batteries. However, in order to take advantage of the PHV vehicle feature that significantly improves fuel economy, frequent charging is recommended.
In response to the question of how the fuel efficiency potential of the PHV could be further increased, analysis of data from these trials indicates that by simply increasing the frequency of charges, a whopping 80% reduction in fuel consumption is possible.(see diagram, below)
note: A "trip" is the unit counting driving excursions [i.e. from the start to finish of one excursion]
To make this possible, frequent charging should be made easy. Efforts are necessary to improve convenience of charging in both the vehicle and in the infrastructure. In addition, further technology development is needed to improve energy efficiency to cope with factors that reduce the EV cruising range such as outside temperature changes and driving conditions like uphill driving, acceleration on the highway.