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Realizing Vehicle to Grid economically and quickly

While the electric vehicle has captured the consumer's imagination and touched an eco-sensitive nerve, it comes with some tough questions that need to be answered. Electric vehicles are being marketed as a green solution to an increasingly environmentally-sensitive market that can achieve the equivalent of 100+ miles per gallon but, there are concerns as to whether the electric grid, in its current form and future iterations, will be able to meet the added demand of that electric vehicles will bring.

Most electricity distribution systems are not designed for the increase in load that results from the use of electric vehicles. To give a sense of scale:

  • a single recharge of a modern vehicle uses approximately doubles the daily energy consumption of a typical US household
  • if consumers could recharge an electric vehicle in three minutes, similar to the average amount of time needed to refuel a conventional vehicle, it would only takes approximately one million vehicles recharging at that speed to exceed the total 2008 capacity of the US grid
Uncontrolled, the increased energy consumption from millions of electric vehicles on the grid could drive up the cost of electricity and result in an outcome that is opposite to that desired: the possibility of increased demand, emissions, cost and outages.

Significant investment is needed in our electrical infrastructure if we are to avoid the potential negative outcomes of increased Vehicle to Grid (V2G) consumption. In theory, this could mean years before V2G is realized on a wide scale due to the massive capital programs needed to increase the overall capacity and distribution infrastructure.

Or does it? Could V2G be achieved quickly and cheaply?

Maximizing speed and scale can be resolved almost entirely within a vehicle by combining smart batteries with energy and location-aware services. Existing solutions can be adapted so that they manage the vehicle's load through direct connectivity between the vehicle and the grid. Vehicles can be made sensitive to the state of the electrical grid they are connected to by reading dynamic price signals directly for that location that can even increase the flexibility and capacity of the grid. The smart battery controls the vehicles charge and discharge unit in response to that information and also through user-configured preferences that:

  • Charge only when it is most economically feasible
  • Stop charging when load shedding or blackouts are threatened
  • Potentially generates revenue for the vehicle owner when the grid is under stress conditions and electricity price more than offsets battery discharge costs
  • Maximize the battery life by optimizing the charging profile
Electric vehicles equipped with smart batteries on a large scale are capable of changing the balance of the grid equation so that many of the goals of smart grid are achieved and the result is a more reliable grid. Location, time, price, current charging status and usage are the dynamic properties needed in every electric vehicle that facilitate:
  • Location and time-based capabilities through GPS so that local charging options and tariffs can be determined
  • Optimized charging stops for price and battery life when on long journeys
  • Customer identity for billing and settlement purposes
  • Cellular telecom access to a central Smart Pricing system
  • Control over the vehicle's charge and discharge unit
  • Metered consumption and generation readings
  • Configuration rules that automatically enable and disable the charge/ discharge unit depending on the vehicles internal power state, next drive time, charging outlet capacity and electricity price
On the grid side, a smart dynamic pricing system is needed in each geographic region of the grid that accepts and rejects charge or discharge requests from vehicles and sets the charge or discharge price depending on current prices and load conditions. No utilities have yet set up such a system but the components are all available and can be readily adapted. The cost of such a program would be insignificant compared to capital programs for upgrading the generation, transmission or distribution system.

There are significant drivers for Vehicle to Grid, much more so than even several years ago. Major auto manufacturers are investing in electric vehicles; Nissan's Leaf, Chevrolet's Volt and upcoming releases from Daimler, Ford, Mitsubishi, and Volvo. But those investments might be reduced without a coordinated solution that integrates vehicles and the electric grid. Smart solutions are capable of providing the necessary control that will allow the electric grid capacity and capability to increase in an orderly fashion to meet the new demands created by the emerging and powerful electric vehicle market.

The author would like to recognize Edmond Cunningham, Birgit Seeger, and Steve Watts for their contributions to this article.

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