It’s been two weeks since our last blog on hydrogen, so we’re back again with the latest installment of what has become something of a “Hydrogen 101” course. As with any college course, the time comes to review some material, in preparation for what will be our “final” on the subject, a one-day virtual conference in late June. No, today’s blog won’t be a repeat of what we discussed before, but we thought it would be helpful to look over the various hydrogen production pathways we have discussed so far this year, this time focusing on the drivers, advantages and disadvantages, and how they relate to each other. Finally, we will also review the general carbon intensity of each approach to producing H2, a method that we think will eventually replace the somewhat flawed hydrogen “color” scheme. In today’s blog, we draw upon our recent coverage of hydrogen production technologies and put them in perspective.
If you’ve been following our hydrogen series, you’ll know that we’ve covered many of the basics about the fuel, from how it’s produced to the various conversions needed to put that production into terms that a traditional hydrocarbon analyst can understand. With that foundation established, we wanted to use this space today to review the various pathways to H2 production, adding some color to the pros and cons of each, and discuss their carbon intensity (CI; See Come Clean for a little more color on how CI is calculated). We’re not ready yet to call a winner among hydrogen production technologies and, in the long run, an undisputed champion may be less likely than a combination of various H2 production methods or other low-carbon initiatives. Regardless, though, we’ve picked up enough information over the last few months to at least start to frame up the key drivers around some of the main production methods in use or under consideration for H2. With that, let’s take a spin through what we know so far for what we consider the “upstream” sector of hydrogen, starting with the most common production method in use today.
Hydrogen via Steam Methane Reforming (SMR) of Fossil-Based Natural Gas
Back in January, in our first hydrogen blog of the year, we focused on two primary production methods, steam methane reforming (SMR) and electrolysis. Our review starts with SMR, a simplified process flow shown in Figure 1. As you may recall from the blog, SMR is how almost all hydrogen is made, and the natural gas feedstock used in the process is almost entirely derived from fossil fuels (we’ll discuss one of the exceptions at the end of this blog). What’s more, most SMR units end up emitting carbon dioxide (CO2) produced during the process into the atmosphere, either directly or indirectly. As a result, SMR using natural gas is considered carbon-intensive and is a relatively large contributor to overall carbon emissions. For this reason, it is somewhat arbitrarily labeled “gray hydrogen,” though we admit that the color scheme doesn’t make a whole lot of sense. What’s really important, is the process’s carbon intensity, or CI. We will have to save a more detailed review of CI calculations for later, as it’s more of a “Hydrogen 201” subject, but let’s just say for now that the CI of SMR using pipeline natural gas from a shale play is high, meaning it’s not considered environmentally friendly from a greenhouse gas (GHG) standpoint.
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