Down under electric vehicles are harnessing plug-in hybrids to not only reduce greenhouse emissions and lower transportation costs, but also to make smarter use of energy from the grid by charging at night during periods of low demand, then supplying any excess charge back to the grid during periods of high demand during the day.

Australia is aiming to become the first country to integrate electric cars into a nationwide smart grid. Its Plug-In Hybrid Electric Vehicle (PHEV) trial taking place over the next three months is part of a National Research Flagship Program called Energy Transformed. Run by Australia's national science agency--the Commonwealth Scientific and Industrial Research Organization (CSIRO)--the Plug-In Hybrid Electric Vehicle trial precedes potential stimulus subsidies aimed at encouraging consumers to adopt electric vehicles.

For the trial, standard Toyota Prius hybrid electric vehicles (HEVs) were converted into plug-in hybrid electric vehicles (PHEVs) by adding a grid-ready battery charger and replacing the existing battery pack with one five times larger--a 30 amp-hour (Ah) nickel-metal-hydride (NiMH) battery capable of holding a 6-kilowatt (kw) charge. The larger battery and charger enable the cars to run all day without using their gasoline engines, even at highway speeds, then be recharged at night by plugging directly into the electricity grid.

The three-month trial period will use drivers who are employees of the Victorian energy distributor SP AusNet. SP AusNet will put the converted Prius' through their paces, using them as all-electric cars for both work and leisure. All the while on-board sensors will be keeping track of speed, acceleration, mileage, emissions and other data useful in evaluating the pros and cons of electric vehicles in general, and the plug-in hybrid approach in particular.

Two other cooperating programs under the Energy Transformed flagship will dovetail with the Plug-In Hybrid Electric Vehicle program, enabling electric cars to become mobile energy storage devices that smooth out grid demand. Called the Electric Driveway program and the Zero Emission Home (ZEH) program, the idea is to attach the Plug-In Hybrid Electric Vehicle to the grid in the Electric Driveway with a smart meter that charges it at night when demand is low. Any excess energy not used for driving can then be supplied back to the Zero Emission Home during periods of peak demand, thereby making the grid more stable despite the fact that it will be drawn upon at night to charge all those electric-vehicle batteries.

If the trial is successful, Australian legislation will be proposed to offer national stimulus subsidies to encourage consumers to switch over to electric vehicles plugged into a smart grid. Together the Plug-In Hybrid Electric Vehicle, Electric Driveway and Zero-Emission Home programs could lower Australia's total greenhouse gas emissions by as much as 14 percent.