Back in the early days of motoring, cars were sometimes called upon to do double-duty. It wasn’t unusual, for example, for a farmer to jack up his Ford Model T, pop off a wheel, and attach a belt to the hub to run equipment.

That’s not the case today, but cars may still play a role in our infrastructure, as Nissan recently demonstrated at an event in Barrie, Ontario. 

The all-electric Leaf usually takes electricity from the grid, storing it in its lithium-ion battery and then using it for propulsion. In future, though, that stored electricity could be sent back into the house, powering it during an electrical outage, augmenting the grid during peak hours, or even selling it back to the utility company.

“As the grid grows and gets smarter, and as infrastructure comes on line, the consumer’s going to look for alternatives and flexibility,” said Allen Childs, president of Nissan Canada. “This adds value in that it’s a supply source to the home when the normal supply is interrupted.”

The system is called Vehicle-to-Home, or V2H, and was developed by Nissan. The Ontario event marked its first demonstration in North America, but it’s just the beginning of the research project, Nissan said. There’s no timeframe on when it will be available commercially in Canada, although the system is set to go on sale in Japan in late June 2012. Energy provider PowerStream was also part of the demonstration, which took place at Barrie’s Georgian College.

From the consumer’s point of view, the system is very simple. The car gets plugged into a power control system, or PCS, which in turn is wired into the house’s main breaker panel. When the Leaf needs to be charged, power flows from the grid into the car’s battery, as it does with its current charging system. 
When the house requires electricity, though, the PCS reverses the flow, taking stored electricity from the Leaf’s battery and running it into the house’s main breaker panel and then to the various outlets in the building.

Nissan estimates that a fully-charged Leaf would have enough electricity to power a typical Japanese home for two days. In Canada, where houses are usually larger and have more equipment, the car’s battery could be expected to run the house for a day. 
Nissan says that the output is enough to simultaneously run an air conditioner, stove, refrigerator, washing machine and dryer.

However, the idea isn’t simply that the Leaf becomes a four-wheeled electricity generator during power outages, which after all are relatively rare. While it can be used for that—and could be of far more importance in Japan, which has suffered through massive earthquakes that have cut off the power supply—the main goal is for the Leaf to eventually become part of the electric infrastructure, the company said.

Electricity is used as soon as it’s made. This creates a steady supply but with various rates of demand, which results in peak- and off-peak hours. “You can’t turn the (nuclear generators) down,” said Ron Groves, manager of industry partnerships for Plug’nDrive Ontario, a public awareness group dedicated to electric vehicle adoption. 

“In Ontario, we have a lot of surplus off-peak electricity, and instead of wasting it, we sell it to the U.S. It would be great if we could use it here. We import and pay for 100 per cent of our gasoline in Ontario, but we produce 100 per cent of our power here in Ontario, so why not keep our money in Ontario and use the electricity?”

The ultimate goal for the program is to use the Leaf’s battery to supplement the power coming into the house from the utility company. After charging the Leaf during off-peak hours, when electricity is at its lowest cost, consumers might then offset some of the most expensive peak-hour electricity by “mixing in” some of the Leaf’s stored power. 

They might also be able to sell some of that power back. “It’s three p.m. on an August day, every air conditioner is flat-out and the grid is groaning,” Groves said. “The grid now says to the cars plugged in, ‘I’m willing to buy your electricity.’ You charged your car at seven cents, but you’re going to sell some back at twenty. Instead of your car being a revenue sucker, it’s a revenue producer.”

Of course, by now you’re asking the obvious question: if you’ve sold your car’s battery power back to the grid, or used it to help run your household, what do you do when you want to drive somewhere? This is where V2H is still in its infancy, as the smart grid infrastructure needs to grow with it. It also illustrates the limitations that electric vehicles naturally have, and that owners will have to work around to make the system work.

The Leaf and the PCS unit would need to communicate with the grid, and the vehicle’s owner would have to program the vehicle’s charging and discharging cycles to suit his or her needs. Knowing how much range you need for your daily drive, you would program the Leaf to power the house or sell electricity back to the grid until that threshold is met. The car would then stop supplying power, retaining what’s needed for the driving you plan to do.

Currently, almost all electric vehicles are being charged on 240-volt home or office stations, but quick-charge DC connections are also planned as part of the overall vehicle-charging structure.

A scenario might involve selling electricity from the Leaf back to the grid during peak hours, and later on, quick-charging it on DC at off-peak, which takes about 25 minutes to bring the battery up to about 80 per cent, to take the car out for driving.

So why not simply have the utility company store electricity when a surplus is created, such as in big buildings filled with storage batteries? “It would be hugely expensive and impractical,” Groves said. “What we’re witnessing here are the first steps of a practical way of doing it.”

Whether or not such a project will work on a large scale remains to be seen, of course. The V2H system can only be viable if several aspects eventually come together: electric vehicles need to be sold in volume, a “smart” power grid has to be in place, and households need to install the power control system and be willing to schedule driving hours and distances. 

It’s a chicken-and-egg equation, but just as cell phone towers initially had to be built even though very few people owned mobile phones—and look how that turned out—it all has to start somewhere.