Many tout electric cars as the next green revolution in transportation technology. Electric vehicles don’t rely on combustion engines like traditional vehicles do and therefore don’t emit noxious pollutants and carbon dioxide into the atmosphere. On this front, electric vehicles certainly have an environmental advantage. And on the back side of things, electric vehicles can be powered by solar panels rather than coal-power grid electricity, offering yet another advantage for consumers to green their transportation.The thing is that you can't only look at how something behaves in one context and claim it covers its entire life - and therein lies the problem with electric cars. Opponents of electric vehicles claim that the resources that go into making electric vehicles not only negate all of the environmental positives of running an electric car, but surpass them. In particular, they point to research that shows electric vehicles aren’t as green as they’re cracked up to be when they’re being manufactured, with a big question mark around the batteries. And they’re right – most studies show that the environmental impact of making electric vehicles is greater than making other vehicles. A British study commissioned in 2010 found that when you considered the entire life span of a car, a mid-size electric car would produce 23.1 tonnes of CO2 over its lifetime, compared with 24 tonnes for a similar petrol car. The problem is the batteries. They use more energy and resources and emit more greenhouse gases during the manufacturing process - 50 percent more. The production of batteries includes materials such as lithium, copper and refined silicon, which require much energy to be processed.And it doesn't end there. At this point in technological development, most electric cars will need a replacement battery after a few years. Once the emissions from producing the second battery are added in, the total CO2 from producing an electric car rises to 12.6 tonnes, compared with 5.6 tonnes for a petrol car. Disposal of the spent battery also produces double the emissions because of the energy consumed in recovering and recycling metals in the battery. Before you rush out to buy a small, efficient diesel car until technology improves, the problem with all these 'numbers' is that the carbon emissions during manufacturing depends on how electricity is produced at the manufacturing point. Countries like Australia predominately use coal based fuel and can emit up to four times as much carbon as those with low carbon emissions. (You can get the more detailed report from Shrink That Footprint). The truth is that Australian electricity production is pretty much the dirtiest in the world in terms of carbon emissions so there is also the matter of the ongoing electricity supply, if you don't have solar on your roof.Long story short – electric cars in Australia may not be as green as you’d hope, but they’re still heading in the right direction. And we clean up our electricity generation act and as technologies improve, we’re likely to see even less impactful electric cars.