A new study by the National Research Council estimates that up to 2 million hydrogen-fueled vehicles could be on American roads by 2020, with that number potentially rising to 25 million a decade later. However, getting there requires getting past a number of hurdles first. The cost of fuel cells must drop and fueling infrastructure must be put in place. That will take substantial subsidies on the part of both government and manufacturers. The study authors estimate that about $200 billion would be required over the next 15 years to make this happen with $55 billion of that coming from governments and the rest from private industry. That total includes costs for vehicle development and deployment, research and development and infrastructure deployment. In contrast, US ethanol subsidies will reach about $15 billion annually by 2020. Beyond 2023, the costs are expected to drop to the point where the lifetime cost of fuel cell vehicles the fuel to propel them would be competitive with conventional vehicles, making subsidies unnecessary.