In their decades-long efforts to develop effective and affordable climate change policy, most western governments have put a lot of money and effort in two areas: (1) hydrogen, and (2) carbon capture and sequestration. They are on the right track, but they’re going about it in a roundabout way. That could set back progress by decades.
A case in point. The Obama administration recently chopped the U.S. hydrogen fuel cell program by $100 million (see article). This prompted a high level fuel cell advisory board member, a former auto executive, to resign. He told energy secretary Steven Chu he is tired of “debating people who … have never touched real hardware … or dealt with real customers.” His displeasure was echoed, more diplomatically of course, by auto industry executives in companies that have substantial fuel cell programs. Secretary Chu explained his decision this way: “We asked ourselves, Is it likely in the next ten or fifteen years that we can convert to a hydrogen car economy? The answer, we felt, was no.”
Who’s right? If the debate is about powering cars directly with hydrogen, either with a fuel cell or as liquid fuel in an internal combustion engine, then the energy secretary is right.
The most obvious glitch in this version of the hydrogen economy is refueling infrastructure: we would need to figure out how to make hydrogen, which is hard to handle, even more available than gasoline. Then we have to overcome the fact that it has lower energy value, by volume, than gasoline and diesel.
And those are not the only problems. To make the hydrogen economy happen, we need to manufacture hydrogen on an unprecedented scale. If hydrogen is to be truly clean, we have to make it differently than the way we do today. Today, we make hydrogen by splitting natural gas into its hydrogen and carbon components. The carbon component is released to the atmosphere in the form of carbon dioxide, which is the principal man-made greenhouse gas (GHG). This process requires high temperature steam, and guess how we heat the water to make steam. In nearly every case, by burning natural gas.
Proposals for alternatives to this are similar to those for developing low-carbon electricity. As with electricity, the most touted proposals—electrolyzing water with solar- or wind-generated electricity—are also the least efficient and the least able to provide hydrogen on the industrial scale. These non-viable proposals have the effect of making the hydrogen economy a non-believable near term scenario. Hence the U.S. energy secretary’s skepticism, and hence the budget cut.
The same goes with carbon capture and sequestration (CCS). The capture part is possible; we already know how to capture CO2 from power plant exhaust. But it’s the sequestration part of it that makes everyone pause. North American power plants emit more than two billion tonnes of CO2 into the air every year. Are we really going to pump even a percentage of that into the ground, year after year?
Both hydrogen and carbon capture have the potential to cut greenhouse gas emissions on a massive scale, without causing the economy to skip a beat. But for that to work, within a reasonable time, we have to shift our focus away from fuel cells and carbon sequestration. Carbon capture and recycle (CCR), which I have described elsewhere, turns CO2 into a valuable feed for low-carbon hydrocarbon fuels. Hydrocarbon fuels have much better energy content than pure hydrogen. If their carbon component were recycled from power plant exhaust, then we’re looking at truly major emission reductions—without having to develop new distribution infrastructure or engine technology.
This all hangs on our ability to manufacture low-carbon hydrogen on a massive scale. And that means developing better ways than conventional water electrolysis using wind or solar power. The two most promising approaches are splitting water with (1) solar light, and (2) nuclear energy to provide heat and electricity. For more detail, see this article.
Plug-in hybrid electric/gasoline cars—another easily achievable technological adjustment—are the way we are going to chop car emissions while reducing dependence on foreign oil. If the gasoline that powers these hybrids is made from recycled coal-plant carbon, the net emission reductions will be huge.
Hybrid cars whose internal combustion engine components ran on recycled carbon fuel would be the greatest and most effective application of the 3 Rs—reduce, reuse, and recycle—since the phrase was coined in the 1970s.
We can achieve this sooner rather than later, but we need to shift emphasis. So let’s support hydrogen and carbon capture and, for the time being, forget about fuel cells.