The first known instance of a plug-in hybrid car going up in flames occurred on June 7 in Columbia, South Carolina to a 2008 Prius that had been converted to plug-in capability for the Central Electric Power Cooperative. The conversion was performed with a Hybrids-Plus PHEV15 conversion kit that uses an A123 Systems lithium ion battery pack. The incident is still under investigation by Phoenix, Arizona-based Electric Transportation Engineering Corporation. Initial information indicates the fire may have been triggered by something related to the on-board battery charger and the car had previously experienced some mechanical issues related to that.

Unfortunately, the car didn't have a data logging system installed which might have helped to isolate the cause. No one was injured and the battery pack sustained some damage but was apparently intact and functional - implying that it was not the cause of the fire. What this points out is that before plug-in hybrids and EVs are brought to market a lot of engineering and validation testing needs to be done to ensure that all systems in the car are safe, durable and properly integrated. This is actually the part of vehicle development that often takes the most time. It's not just the batteries that have to work, but all the bits and pieces around it. That's why it's taking almost four years from concept to production for the Volt and why Toyota is in no rush to bring the PHEV Prius to market.

[Source: Cooperative Research Network, thanks to the un-named reader for the tip!]

Last year, Google made some waves when they announced the RechargeIT project to convert a fleet of Toyota Priuses and Ford Escape hybrids to plug-in capability. The company has just issued their first progress report on the program, and the results may be disappointing for those promoting plug-in conversions. Right now the only way to get a plug-in hybrid is to buy an off-the shelf model like the Prius or Escape and than install a $10-15,000 conversion kit. Unfortunately, as we learned from a recent interview with GM's Pete Savagian, a conversion PHEV provides a limited additional benefit over a conventional parallel hybrid because the motors typically don't have enough power to drive the vehicle under most conditions without the engine turning on.

The other issue is that as fuel efficiency increases, the incremental savings in fuel use actually decrease. This is more apparent if you use the European units of fuel consumption which is measured in L/100km. If consumption is reduced from 12L/100km (19.6mpg) to 6L/100km (39.2mpg) you would save 6L on a 100km trip. Doubling mileage again going to 3L/100km (78.2mpg) only saves an additional 3L. This is apparent when you take an already efficient car like the Prius which starts at 44.6mpg and increase it to the 66.2mpg that Google saw. The result over 12,000 miles of annual driving is 88 gallons of fuel saved. At $3/gal, that's $158/year (after factoring in electricity costs). At that rate the $15,000 conversion would take 95 years to recover the cost. Ouch.

Google points out that most of the driving was on short runs where the engine often runs early in the drive to power certain vehicle subsystems. Longer runs would increase the mileage further, but you still have the issue of diminishing returns. With gas at $5/gal and a conversion cost of $10,000, the payback drops to a mere thirty years. Until vehicles are actually engineered from the ground up as PHEVs and mass produced to bring down cost, the cost benefits simply won't be realized by people doing conversions. Reduced emissions and oil use, though, should still take place.

[Source: Google.org via CNet]

Earlier this summer Toyota announced plans to start testing some plug-in versions of the Prius in Japan. That announcement was quickly followed by two of the PHEV Priuses coming to California and now the program is hopping another ocean. Following up on the rumors circulating over the weekend, European energy company EDF has struck a deal with Toyota to test some of the plug-in hybrids in France.

Toyota and EDF have collaborated on a charging and billing system that can be used with public charging stations. The Priuses to be tested in EDF's fleet will be equipped with the new system and will start running this fall. The press release from Toyota Europe is after the jump.

[Source: Toyota]

I'm just going to assume you've heard that Toyota is testing a plug-in Prius on public roads in Japan. If this has slipped by you, check out the links below. Otherwise, you know that the PHEV uses the standard nickel metal hydride batteries, not new and fancy lithium ion batteries. So, what does the plug-in NiMH give you? BusinessWeek fills us in.

First, the PHEV is 100 kilograms (220 pounds) heavier than the standard Prius. The larger battery means there's no room for a spare tire. The test models can go just 13 kilometers on electric power alone, and the 1.5-liter gas engine kicks in any time the speed goes over 100 kmh (the current Prius' gas engine starts up at 68 kmh). The batteries recharge in 60-90 minutes at 200 volts or 3-4 hours at 100 volts.

If emissions are all you're concerned about, the PHEV Prius looks good. Probably. Even with the excess weight and figuring in "emissions created in the production of the electricity used to recharge the batteries" (BusinessWeek's phrase), is cleaner than current hybrids. BusinessWeek explains the differences depending on where you plug it in:

However, the level of emissions reduction varies from country to country, depending on how the electricity is produced. In France, which relies heavily on nuclear power, the projected carbon dioxide reduction could be as much 45%, Toyota estimates. But in the U.S., where most energy is created by burning fossil fuels, the benefits are far smaller, at an estimated 4%. Toyota says those benefits could be boosted by the use of biofuels, which the plug-in Prius accepts.

So, the plug-in Prius - as it's being tested right now - nets us just four percent decrease in CO2 emissions. The good news is that that number can only get greener.

Related:

• Toyota gets Japanese approval for PHEV Prius road tests
• Toyota will test plug-in Prius, with li-ion packs, in Japan

[Source: BusinessWeek]