Last summer, Karl Stracke, the vice president of global vehicle engineering of General Motors, said the company planned to test three battery-electric vehicles in different global regions.

This morning, the company's Opel unit announced that it would test a fleet of Opel Meriva small minivans converted to electric power in Germany.

Opel is launching the test in conjunction with German power company MeRegioMobil. GM didn't specify the size of the electric Meriva fleet.

2010 Opel Meriva leak

2010 Opel Meriva leak

Goal: Electric cars as energy storage

With leisurely acceleration and a mere 40-mile electric range, the fleet of MeRegioMobil Merivas is not a particularly advanced demonstration of electric-drive technology per se.

Instead, the Opels are intended to take part in much wider and more complex tests to evaluate whether electric cars can also serve as energy-storage devices in future smart electric grids when they're not being driven.

Among the technologies to be tested are bi-directional communications and vehicle-to-grid (V2G) charging technology. The test has been funded by Germany's Ministry of Economics and Technology.

Charging that goes both ways

The Meriva BEV can be recharged both from standard European 230-Volt household power and three-phase power at 400 Volts, known as high-speed charging. The car is capable of feeding electricity back into the grid through its bi-directional charging system.

The idea behind V2G technology, which most analysts agree is still many years ahead, is that electric utilities could draw a small amount of electricity from each battery in an unused electric car to provide power at peak demand periods. It would only happen with the owner's consent, and owners would likely be paid back for the power taken.

2010 Opel Meriva leak

2010 Opel Meriva leak

Years or decades ahead

Most analysts agree that any widespread deployment of V2G technology is still many years ahead. Among other things, it will require enough electric cars on the road that tens of thousands of them are parked and connected to smart grids that have not yet been installed.

That combination of factors may not happen during this decade, except perhaps in limited areas.

Small minivan

The Opel Meriva is a small five-seat "people carrier" that's built on the same platform as the short-lived 2008 Saturn Astra. The electric version has only four seats, likely reflecting a battery pack that widens the tunnel down the middle of the passenger compartment.

The 3500-pound MeRegioMobil Meriva offers just 40 miles of range from a 16-kilowatt-hour lithium-ion battery pack--almost like a 2011 Chevrolet Volt minus its range-extending gasoline engine.

2008 Opel Meriva Concept

2008 Opel Meriva Concept

Leisurely acceleration

Acceleration is leisurely from the 60-kilowatt electric motor that powers the front wheels. (there's also a Sport mode providing up to 80 kW). The 0 to 62 mph time is 11 seconds, and top speed is limited to 80 mph.

But as GM stresses several times in its release, the MeRegionMobile Meriva is more about testing the two-way charging than it is about actual electric transportation. The test is being conducted by a consortium that also includes Daimler, Bosch, SAP, and three German research institutes and universities.

The Opel Meriva BEV follows two previous all-electric vehicles announced this summer: a fleet of electric Chevrolet Sail EV minicars for China, and just last week, an all-electric 2011 Chevrolet Cruze EV with a 100-mile range, to be tested in South Korea.

It's also worth noting that rumors persist around the idea that GM may develop an all-electric version of the current 2011 Chevy Volt within a few years.

[General Motors]