It is very important to understand that if you do not have access to generate or purchase green energy then converting a vehicle to electric power might have a NEGATIVE impact on the environment.
For instance, in Australia, 90% of the electricity is generated using coal as the fuel source. Coal is a very inefficient fuel and creates 1kg of CO2 greenhouse gases per usable kWh which is as much or more than car petrol engine.
See this study www.ilea.org/lcas/taharaetal2001.html
What is green energy?
For information about which companies in Australia provide green energy try this site; http://www.cana.net.au/electricitywatch/
For more general information about green energy in Australia try this site; www.greenpower.com.au