The fierce debate over the prospects for hydrogen as a clean, renewable energy source for the future has dragged on for decades. The pro-hydrogen forces periodically trumpet important breakthroughs, only to be knocked back by disappointing setbacks. It seems that hydrogen's real-world feasibility has been "just around the corner" since the 1970s.
Hydrogen advocates have long touted the invisible gas as an abundant, potent, storable, non-polluting form of chemical energy - and it is indeed all of these. Hydrogen is the most common element in the universe. Every nation can produce it and hydrogen will never run out.
One of its unflagging champions is Peter Hoffmann, the German-American editor and publisher, who has weighed in on behalf of hydrogen for years and his revised classic, Tomorrow's Energy, brings us right up to date with scientific and commercial developments, as well as the often turbulent political discussion.
His argument is that hydrogen technology, in the form of fuel cells, is, well, just around the corner; all that's needed is for policymakers to wake up, dig a bit deeper in their pockets to provide more R&D funding, and start laying an infrastructure for fuel cell-powered mobility. This will be the beginning of the age of hydrogen, which has the potential, eventually, to consign the hydrocarbon economy to the dustbin of history. This bigger goal, though, is a long way down the road in the estimation of almost everyone.
The facts about hydrogen, at least, are undisputed: it does not exist freely in nature; most hydrogen is bonded to oxygen in water. It must be generated by splitting it from a compound like water or hydrocarbons like natural gas, oil, coal or plant sugars. Thus, hydrogen is not a primary energy source, like oil, but more of an energy carrier, like electricity. It requires another primary energy source to produce it, which could be renewable, nuclear or fossil. It stores energy that is released cleanly when it is discharged "like the spring in a mousetrap", noted one observer.
Hydrogen takes different forms - gas, liquid, or even solid - and is a staple in many industries for the production of fertilisers, drugs and plastics. It converts heavy petroleum into lighter forms suitable for use as fuels.
Hydrogen has several potential roles as the fuel of the future. It can be burnt in modified internal combustion engines - like those of jets, turbines, four-strokes and diesels. Over the years, considerable R&D has been expended on this option, but it has never been ready for prime time. Its success is ultimately the key to the "hydrogen economy" utopia that is dreamed of by such renowned voices as Jeremy Rifkin, the US economist and social thinker.
The best bet these days are hydrogen fuel cells, which can be used in motor vehicles to store and create electricity. These cells are little electrochemical factories that combine hydrogen and oxygen in a flameless process that produces electricity. Today most hydrogen is generated with fossil fuels, thus making it a fellow contributor to global warming. But this process can also be clean and green if based on renewables, and thus could power future generations of electric cars and the only emission coming out of an exhaust pipe would be innocuous, run-of-the-mill steam.
Among hydrogen enthusiasts, fuel cells are the embryo of the hydrogen economy. Fuel cells, argues Hoffmann, "have become widely recognised as a vanguard technology that may launch hydrogen energy on its way to becoming a major environmentally benign, sustainable, renewable component of the world's energy mix for both transportation and stationary applications". By "stationary applications" he means heating homes.
The future, claims Hoffmann, is (almost) now - and he is joined by many experts, industry leaders and policymakers, above all in Europe and Japan. There are already hundreds of pilot electric cars on the road that run on fuel cells converting hydrogen into electricity. They have the same basic drivetrains as electric vehicles, but they have fuel cells instead of batteries. The cells, they argue, are much closer to ready than the current e-car batteries, which have never lived up to expectations, despite decades of research.
Major car makers, among them the German giants BMW and Daimler-Benz, claim they will be mass producing hydrogen cars for public sale by 2015. Three of Mercedes' B-class F-cell cars circled the globe last year. California approved new regulations that could put more than 160,000 zero-emission hydrogen cell cars on the road by 2025. General Motor's fleet of 115 Chevrolet Equinox fuel-cell vehicles has chalked more than 750,000 miles. By 2020, economies of scale and technological advancements could bring down their costs by 90 per cent, says a widely circulated McKinsey study.
So, why is it then that US President Barack Obama's energy secretary, Steven Chu, a Nobel Prize-winning physicist, has tried to cut hundreds of millions of dollars in funding for hydrogen fuel cells in the United States?
In 2009 he claimed that "you need four miracles" to make fuel-cell powered cars a reality, and that the money could be much better spent on other, more promising green energy developments.
Detractors like Chu point to hydrogen's prohibitive costs: fuel cells require platinum, which is enormously expensive. Even optimistic car makers estimate that a hydrogen car will cost around $50,000 in 2015. Nor does Chu like the fact that natural gas, ultimately a finite fossil fuel, is needed to create hydrogen in the first place.
Moreover, the tanks that hold hydrogen are still much too heavy. There have to be stunning advances in the storing mechanism for it to be the fuel of the future. Indeed, the biggest obstacle is the network of hydrogen refuelling stations needed to charge h-cars. There are about 65 hydrogen stations in the United States, and only 180 worldwide.
Just to show how up for grabs the hydrogen debate remains, both houses of the US Congress - Democrats and Republicans alike - have overturned Chu's cuts and not only restored the millions in research funding, but also added to it.
"We believe domestic manufacturers are on the verge of the full-scale commercialisation of fuel-cell systems and hydrogen energy technologies," congressmen told Chu in a statement that didn't once use the words "just around the corner".
Paul Hockenos is the author of Joschka Fischer and the Making of the Berlin Republic: An Alternative History of Postwar Germany.