Smart Grid technologies promise a major overhaul of the aging energy infrastructure. With the addition of alternate, sustainable energy sources to smart meters in homes and businesses, changes are sure to come fast and furious. And one of the more critical aspects of the Smart Grid is the emergence of electric vehicles (EVs) and plug-in hybrid vehicles (PHEVs).
These mobile loads and potential energy sources will have to tap into the Smart Grid, but not necessarily at the same location on a daily basis. Imagine several EV owners gathering at a meeting or a party, and during this time they want to charge their vehicles. The impact on the local transformer could be quite significant. As a result, EVs and PHEVs need to connect and communicate for an effective Smart Grid. For that to happen, standards must fall into place and technologies need to advance.
The success of EVs and PHEVs, collectively called plug-in electric vehicles (PEVs), depends heavily on an effective charging infrastructure. For example, GM has deployed three EVs into outer space, said Tony Posawatz, vehicle line director for the Chevrolet Volt and global electric vehicle development at General Motors during his presentation at the Plug-in 2009 Conference and Exposition last August in Long Beach, Calif. In fact, the Apollo 17 vehicle achieved 22 miles of “real world” EV range. But the program was scrapped due to the lack of a recharging infrastructure on the moon.
READY OR NOT, HERE COME PEVs
While 2010 marks just the beginning of OEM introductions of PEVs in the 21st century in the U.S., the federal government wants to have as many as 1 million EVs and PHEVs on the road by 2015. However, an EV’s requirements for energy could increase a household’s electricity consumption up to 50% or even more.
The Electrification Coalition, a not-for-profit group of business leaders promoting the deployment of EVs, created a 91-page report called the “Electrification Roadmap.” The report envisions that by 2040, 75% of light-duty vehicle miles traveled in the U.S. should be electric miles. To avoid problems down the road, utilities and carmakers are assessing the potential impact of these vehicles on the infrastructure.
An unlikely combination before this decade, utility and automotive companies now frequently share the stage at industry events such as the SAE 2010 World Congress, held April 13-15 in Detroit, Mich. Oliver Hazimeh, director and head of the Global e-Mobility Practice at PRTM, a management consulting firm, organized and chaired a panel titled “Smart Grid Technology: Are Electric Vehicles Part of the Problem or Part of the Solution?”
“In terms of just the barriers that still need to be overcome, clearly there is enough that needs to be happening around the infrastructure, battery costs and educating the customers, actually integrating the whole thing across the ecosystem,” he says. “Those are formidable challenges still ahead.”
THE PERVASIVE NEED FOR STANDARDS
Standards represent a critical first step toward interoperability and seamless integration of PEVs onto the grid. Several standards organizations are working to develop specifications for the Smart Grid, including the SAE for automotive-related standards.
The National Institute of Standards and Technology (NIST) is championing and directing the consolidation of all standards activity. Its NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 1.0, dated January 2010, identifies eight priorities to implement an effective Smart Grid:
• Demand response and consumer energy efficiency
• Wide-area situational awareness
• Energy storage
• Electric transportation
• Advanced metering infrastructure
• Distribution grid management
• Cyber security
• Network communications
Based on the impact of vehicle charging loads, at least three of these priorities integrally involve vehicles. The SAE has several specifications in the works that specifically target automotive requirements. In addition to the recently approved J1772-SAE Electric Vehicle and Plug In Hybrid SAE Electric Vehicle and Plug In Hybrid Electric Vehicle Conductive Charge Coupler, there are:
• J2293/1 & /2: Energy Transfer System for Electric Vehicles
• Part 1: Functional Requirements and System Architectures
• Part 2: Communication Requirements and Network Architecture as well as new SAE documents:
• J2836: Use Cases & General Information
• J2847: Detailed information (messages, state diagrams, etc.)
The connector specified in J1772 (Fig. 1) will be on the Chevrolet Volt and the Nissan Leaf to be introduced at year’s end. Initially, two ac levels are defined for onboard chargers, but work is underway for higher-voltage, fast-rate dc charging (see the table). Unlike the 1990s battle of conductive versus inductive charging for EVs, the present specification only defines conductive charging and is supported by GM, Chrysler, Ford, Toyota, Honda, Nissan, and Tesla Motors.