Specifically, "green diesel" seems like it has potential, as the wikipedia page puts it:
Green diesel, also known as renewable diesel, is a form of diesel fuel which is derived from renewable feedstock rather than the fossil feedstock used in most diesel fuels. Green diesel feedstock can be sourced from a variety oils including canola, algae, jatropha and salicornia in addition to tallow. Green diesel uses tradional fractional distillation to process the oils, not to be confused with biodiesel which is chemically quite different and processed using transesterification.
“Green Diesel” as commonly known in Ireland should not be confused with dyed green diesel sold at a lower tax rate for agriculture purposes, using the dye allows custom officers to determine if a person is using the cheaper diesel in higher taxed applications such as commercial haulage or cars.Algae, which is actually being used in experiments at MIT to determine its propriety with electricity when properly provided with sunlight, is a great alternative. But will it work with cars? I'm not sure...
Brazil has started acquiring "green" fuels, so it has already come into practice, hope it works.