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A group of experts discussed the challenges in developing a future V2G system to incorporate batteries used in electric vehicles and plug-in hybrids into the nation's electrical grid at the SAE 2014 World Congress.

Energy independence and the smart grid

Six experts, ranging from a university professor to a technology manager at a Michigan power company engaged in some spirited give and take in an SAE 2014 World Congress panel discussion titled Energy Independence and the Smart Grid.

The notion at the center of the vehicle-to-grid (V2G) vision that is perhaps most important to the automotive industry is compensation to owners for use of their vehicles. The automotive OEMs would be happy with this, since such compensation could help reduce the cost-differential between electric and gasoline or diesel vehicles. Achieving cost-parity is a key issue with OEMs, especially since they are on the hook to deliver zero emissions vehicle (ZEV) targets to meet regulatory mandates.

Could vehicle owners provide value to electric providers?

One of the biggest issues in using more renewable energy, especially wind and solar, is their variability. The wind is strong sometimes, weak others. The sun sets every night and intermittent clouds interrupt intensity during the day. Making the situation more complex is the fact that demand itself is variable. Electrical grid load profiles vary with season and time of day.

A smart grid with plenty of storage can help match variable demand with variable production, storing energy during times of "overproduction" for future use when needed. Currently, pumped hydro storage is the most effective means of storing energy, but there are limits to how much more can be built. Where to get the extra needed to expand renewables effectively?

One solution just might be battery-equipped vehicles, either battery electric (BEV) or plug-in hybrid electric vehicles (PHEV). Each one represents an untapped resource for grid storage since privately owned vehicles are parked most of the time—in fact 96% of the time. They also have embedded communications and operational flexibility, with embedded smarts like MyFordMobile from Ford that can charge an EV when electricity rates are favorable.

Key challenges

Some of the issues in getting to a V2G reality include both communications and the intelligence in the grid to manage an increasingly complex system. A successful implementation may scale up to a million cars or more, requiring a system to communicate with and control the charge of each EV over a vast network. Who will be in charge? At what speed and frequency will communications operate? Wireless or wired?

One speaker expressed the opinion that there are too many communication standards to choose from. One protocol mentioned was the Open Automated Demand Response Communication Standards (OpenADR), but a number of others were discussed. Other challenges included equipment to effectively charge cars from an intermittent source. Another is the infrastructure to move electricity from low-load areas to where cars are actually parked during the day.

The general consensus seemed to be that these are practical, solvable engineering challenges for getting to a V2G. They need to be addressed of course, and engineering, investment, and hard work is required. However, the larger issue may be the existence of the EV fleet itself. EV adoption is critical to automotive OEMs meeting mandates from the “green states” for ZEV targets. California has a goal of growing the fleet of ZEVs each year. CARB projects more than 200,000 per year of ZEVs by MY2025, which could include a mix of hydrogen fuel cell, PHEVs, and pure BEVs. 

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