As we've presented, the sorting-out process for alternative fuels is well underway. Some, like methanol, have already fallen by the wayside while others such as E85 have stalled. Hybrid and all-electric vehicles promise a continuing rise to stardom while hydrogen fuel cell vehicles may one day be feasible. Clearly there is no single-solution “silver bullet,” as each of the alternatives has limitations and challenges. Technology, infrastructure, legislation and consumer demand will determine the powertrains and fuels of the future.