Dec 03 2018

Taking A Second Look at Hydrogen

There seems to be increasing awareness (and perhaps weakening denial) that we are standing at a critical moment in the history of our civilization. A problem has been looming for decades and we have largely ignored it. Now the effects are starting to be felt, and scientific confidence has only grown stronger over time.

I am talking, of course, about global climate change. There are still significant stragglers, but there is general consensus in the world that we need to urgently decarbonize our civilization. This is definitely one of the greatest challenges that our generation faces, and many suspect the future will judge us largely by how we meet this challenge.

Many groups have rolled up their sleeves, not to just advocate for one or another potential solution, but to chart viable pathways to a zero carbon infrastructure. The bad news is, it won’t be easy and it will cost trillions of dollars. The good news is, we already have the necessary technology and it will save many more trillions of dollars, not to mention disrupted and shortened lives.

A recent article in the Economist goes over the big picture, making a plug for a significant role of hydrogen. They make the good point that we can’t just think about power generation and cars, we have to also think about industry.

Industry is responsible for about 41% of carbon release, mostly in the steel, cement, and chemical production sectors. These are considered “hard-to-abate” uses because they are energy intensive. Lithium-ion batteries will not suffice for the energies needed.

So if we imagine a minimal carbon future (or hopefully net negative carbon, if we include capture technology), we have to include heavy industry. The power production sector is where much attention is being focused, because it is the most obvious. Here 85% of energy still comes from fossil fuel. This will need to be displaced by nuclear power and renewables like solar and wind. The relative contribution of each is still a matter of hot debate, but we’ll leave that to a different time.

The transportation sector is another big chunk. Right now trucks, cars, and planes are mainly directly burning fossil fuels for power. There is a big push to move to electric vehicles, but this is just shifting the energy production from the transportation sector to the power sector. This only helps to decarbonize if we meet this increased need with zero-carbon sources of power. If we build coal-fired power plants to charge up all those Teslas, we have gained nothing.

But this is totally solvable – we move the transportation sector to electric, and the power sector to nuclear, solar, wind and other renewables, and we’re good. Current battery technology is just getting to the point where it is viable for deep market penetration, and it’s getting incrementally better every year. It feels like we’re past a tipping point, and it will only get better.

In this equation, hydrogen has been left out, because battery technology for cars basically won. Hydrogen is the beta-max of zero-emission cars. This was simply due to technology – batteries slowly improved until they got to the point that they were viable, while hydrogen hit some significant road blocks that could not be solved. Essentially researchers could not develop a light-enough, energy dense-enough, and safe-enough option for storing and releasing hydrogen so that everyone would feel comfortable driving around at 60mph next to one.

A lot of this also comes down to infrastructure. Hydrogen technology may get there, but by then we will haveĀ  battery infrastructure and everyone will be happy with their electric cars, so there will be little incentive for massive investment in a hydrogen infrastructure. It’s simply too late.

But this brings us back to industry. Hydrogen may find a role in the hard-to-abate industries, that are more energy intensive and not suitable for current batteries. If you don’t have to drive around with your hydrogen, that solves a lot of problems. We don’t care if we have big heavy storage, if it’s stationary. So what would this infrastructure look like?

First, to be clear, hydrogen is not a source of energy – unlike fossil fuels, which are both a source and convenient storage medium for energy. There is essentially no free hydrogen on Earth. We have to make it. Hydrogen is therefore just a way of storing energy. In that sense it is like a battery. We therefore have to consider where the energy to make hydrogen is coming from.

Right now 95% of hydrogen used for fuel is stripped from fossil fuels. Ack – this makes it mainly just another form of fossil fuel. Only 5% comes from the electrolysis of water (splitting water into hydrogen and oxygen). If a hydrogen infrastructure is going to be of any significant use getting to minimal carbon, we have to make essentially all our hydrogen from water. And the energy for splitting water has to be clean itself.

This is why there is so much focus on so-called “leaf” technology – using solar energy directly to electrolyze water. We need massive efficiency gains in this technology to make it viable. Progress is being made, and we may even be close. This is one of those technologies where I read constantly about baby-step improvements, but it’s hard to get a sense of how close the technology is to prime time.

So even if we never drive a hydrogen car (or it remains a niche market), there may be a critical role for a hydrogen infrastructure in heavy industry. This technology may then trickle down for residential use – burying a “tank” of hydrogen in your yard that can be used for heating your home, or even all your electricity needs (perhaps supplementing your solar panels).

For those who think that having a tank of hydrogen on their property is dangerous, I would remind you that we are pumping highly flammable gas into homes, or storing tanks of flammable oil. Even transmitting high-voltage electricity along lines hanging overhead, or even buried where someone might accidentally dig into them, carries risk. Hydrogen would probably be safer.

Free of the need for storage to be light, small, and stable in a crash, hydrogen may have a future in our energy infrastructure yet.

Others may balk at the huge infrastructure cost, and yes this is always an issue. But at one point we built a massive railroad infrastructure, and electrical grid infrastructure. No one thinks we are going to decarbonize our civilization without some massive infrastructure investment. But we should look at this as an investment, because it will pay us back many fold. It’s simply a matter of planning and investing rationally for the future, rather than thinking myopically only about the current moment.

Of course, if we did that, we wouldn’t be in this situation in the first place.

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