It’s Not Easy Being Green

If you're considering a PHEV or an EV on the grounds that it will reduce CO2 emissions, hold that thought. A new report published in the International Business Times shows that while tailpipe emissions are indeed reduced, the overall carbon cost of a PHEV or EV may be higher than you think, and is likely to be about as high as a number of conventionally powered vehicles.

Most electrical power plants in the United States are fired by coal, natural gas or petroleum, all of which release carbon dioxide into the air. Coal, the most common power plant fuel, releases the most CO2 into the atmosphere as it is burned to make electricity. Natural gas, less commonly used in power plants, is cleaner by a scant 50 percent.

In a head-to-head comparison, an all-electric vehicle such as a Tesla Roadster that charges off of house current might actually be responsible for more CO2 emissions than a Prius or Insight would when the emissions from a coal-fired power plant are taken into consideration. Hybrid cars also emit less CO2 than most highly efficient gasoline-only vehicles and those powered by diesel or "clean diesel" engines.

So do EVs and PHEVs make sense? If you're switching to one from a larger, older or less efficient vehicle, a PHEV or EV can indeed reduce your carbon footprint. The story raises an issue, however, that has been discussed before. The overall impact of large-scale migration to PHEVs, EVs and HEVs won't reduce carbon emissions significantly unless the fossil-fueled power plants are modernized at the same time. Conversion of the plants to natural gas can reduce carbon emission, but the cost of a natural gas-fired plant will substantially increase consumer cost and will reduce the rate at which consumers convert to vehicles with electric drive trains.

One potential alternative is a hydrogen-powered vehicle. BMW has tested its hydrogen FCV at Argonne National Laboratories, and those tests show that the vehicle actually emits air that is slightly cleaner than the air it takes in. Unfortunately, the vehicle won't be mass-produced anytime in the near future because the supporting infrastructure is not yet available.

The moral of the story? If you're buying an alternative-fuel vehicle for environmental reasons, make sure that you're really helping Mother Nature, and not just shifting the problem to someone else's exhaust pipe.

Source: International Business Times

Photo: Courtesy of Toyota