Ethanol (now widely offered) os far more cost effective.
That's only because its production is heavily subsidized. Take away the subsidies and discover ethanol's real cost. Furthermore: Some question ethanol's touted "carbon neutrality," indicating ethanol may take more energy to produce than it creates. Meanwhile: Human and animal food crops are being turned into internal combustion engine "food," creating shortages and raising prices.
Ethanol as a solution to energy needs and pollution may well be a chimera.