Electric vehicles in Houston

Motivations, trends and impacts

CenterPoint Energy Houston Electric, LLC, (CenterPoint Energy) is the regulated electric transmission and distribution (T&D) service provider for over 2 million customers in the Houston, Galveston, and Brazoria areas. For a number of years, CenterPoint Energy has been engaged in the development of the EV market for the Houston region. Recent EV market trends, including numerous vehicle and charging equipment product launches and notable government policies to promote EVs, have indicated a high potential for EV adoption in the near term. However, several uncertainties exist in estimating EV penetration and grid loads over time. CenterPoint Energy recognizes the importance of better understanding the potential grid impacts of EV loads, as part of its effort to facilitate EV market adoption and prepare for successful EV integration.

Project
KEMA and CenterPoint Energy conducted a joint study to assess the potential impacts of EVs on CenterPoint Energy’s Houston-area T&D system over the next decade. Though EV technology spans a number of transportation applications, the study concentrated on lightduty vehicle applications. KEMA used scenario analysis in combination with transportation and electric distribution system data for the Houston area and current product characteristic information to determine expected EV impacts. This method helped address some of the uncertainty in estimating EV penetration and loads on the grid over time. Rather than predict EV penetration—a difficult task with questionable accuracy—the study identified areas of concern and key factors to monitor as the EV market progresses. The study also provided information on general areas related to EV integration
> Discussed importance of transportation electrification to our future and the need to address certain regulatory & rate design issues for successful EV integration
> Reviewed EV technology developments and assessed charging methods and info about operating EVs necessary to facilitate EV purchases
> Identified key public policy issues that drive the EV market

Key results
The study informed program and system planners of the projected range of EV impacts and the vulnerable areas of CenterPoint Energy’s T&D system to facilitate future policy and program planning, and ensure its power systems can accommodate EV integration.

Overall, the study determined that system-wide impacts from EVs are likely to be relatively minimal within the next decade, with additional peak load expected to grow by no more than 5%. The localized impact of EVs, including excessive transformer loads, is of more concern. In particular, the analysis showed potential clustering of EVs, which can result in high EV loads at a given transformer. Low-charging levels during off-peak periods could notably limit overloading.

Client
> CenterPoint Energy Houston Electric, LLC, United States

Project coordinator
> KEMA, United States

Project details
> Duration: April 2010 - June 2010