Elon Musk, who introduced us to his Tesla electric car, scoffed at the notion of a hydrogen fuel cell vehicle. He called it a “fool cell.”

A former U.S. Energy Secretary said that for hydrogen fuel cell cars to become a real choice “they need four miracles, and it only takes three to become a saint.”

But it didn’t take four miracles! And it isn’t a “fool cell.”

Just a few months ago, Toyota announced the world’s first commercial hydrogen fuel cell vehicle for sale. It is call the Mirai (which means “future” in Japanese). Hyundai has also begun leasing its version of the fuel cell vehicle, and Honda just unveiled its latest fuel cell concept car planned for sale next year. Other companies, including Mercedes, GM, Ford, Volkswagen and BMW, are not far behind.

There have been many breathtaking changes in automobiles in recent years. But, for me, the introduction of new hydrogen fuel cell vehicles is a major milestone. This is a car with twice the power to the wheel per unit of energy and it emits only water vapor out of the tailpipe. That sounds like disruptive change to me.

The Toyota Mirai is now being sold in Japan where their government is supporting the development of hydrogen fueling stations. Later this year Toyota will begin selling the Mirai in the California market where the state has a program to develop some of hydrogen fueling stations.

In addition to introducing the Mirai, Toyota has taken an unprecedented step. It announced that it is making all 5,680 patents related to their fuel cell technology available royalty-free in the hopes of driving more innovation.

Dr. Michio Kaku, a theoretical physicist, recently described the fuel cell vehicle as “the perfect car.” He described it as a car using a fuel source that is inexhaustible, an engine with no moving parts, and a tailpipe that emits only water vapor. That statement about “perfection” contains some hyperbole, but he has a point.

In a world concerned about the impact of CO2 emissions on our planet, emission-free vehicles are a friendly answer to the question of what we need to do to combat the dangers of climate change.

In 2009, the U.S. Energy Department’s budget request proposed the elimination of nearly $200 million of federal research projects on hydrogen fuel cells. I disagreed. As chairman of the Senate Appropriations Panel on Energy at the time, I restored that funding. The fact is, we were already seeing fuel cells used successfully in industrial settings and that has continued to grow very rapidly, with over 35,000 shipped in 2013 alone for diverse applications.

Former Energy Secretary Steven Chu, who was skeptical of the fuel cell research, later became a supporter. In fact, he revitalized the program and it’s been further strengthened in the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy under Secretary Ernest Moniz. This has helped cut fuel cell cost 50 percent in the last several years.

The progress announced by Toyota and other companies demonstrates the value of that research.

The progression toward a lower carbon future in transportation is moving from more efficient gasoline engines to hybrids [lto electric vehicles, and now to fuel cell vehicles. And I believe the fuel cell vehicles demonstrate that the future is now.

But there remain some challenges.

Even a so-called “perfect” vehicle needs fueling stations. Nearly all of the fueling stations in the U.S. sell only gasoline. It will require some public sector involvement to incentivize the building of hydrogen fueling stations. And sustained funding for research is needed to further reduce the cost of both fuel cells and hydrogen, especially from renewable.

The government also needs to restore the fuel cell vehicle tax credit that has expired. That incentive continues for electric vehicles, but no longer applies to fuel cell vehicles. This is a mistake that Congress needs to correct.

At a time when CO2 emissions from vehicles are a significant part of the climate change problem, we can now welcome a vehicle that has no carbon emission, has a fuel source that is the most abundant fuel on the planet, and has twice the efficiency of power to the wheel. Further, it emits only water vapor from the tailpipe, has a 300 mile range and can refuel in five minutes.

Is it the perfect vehicle? Probably not. But it’s getting close.