|Coal is to become the largest source of hydrogen starting around 2030. Click to enlarge.|
A report published this fall by Argonne National Laboratory analyzes potential hydrogen demand, production, and cost should the projected shift to a hydrogen-fueled transportation system occur.
Among the conclusions is that coal will match natural gas as the largest source of hydrogen by 2030, and then move into the lead, providing 26.5% of the hydrogen to fuel the hydrogen highway by 2050.
Biomass-derived hydrogen (via gasification) comes in second by 2050, with 23.9%, followed by distributed electrolysis, with 17.6%.
The report writers (researchers from Argonne and TA Engineering) used an optimistic, but intermediate, scenario for hydrogen fuel cell vehicle growth—that FCVs would account for 50% of all light vehicle stock by 2050. (The “President’s Hydrogen Initiative” estimates fuel cell vehicle penetration at nearly 100% by 2050.)
The hydrogen demand in the Argonne scenario is substantial: nearly 5.7 quads (quadrillion BTUs)—the energy of about 45 billion gallons of gasoline.
The researchers approached the issue by factoring in distribution of demand, and availability of proximate resources for the cost-effective production of hydrogen. They do not undertake a well-to-wheels analysis of the energy, greenhouse gas and criteria pollutant emissions involved in each of these pathways.
They assumed that ultimately 24% of all hydrogen demand will be generated in non-metropolitan areas, but that there will be a gradual build-up to that share. Initial non-metropolitan travel is limited to non-metropolitan interstates.
Among the key assumptions for the forecast are:
Each region will produce sufficient H2 to meet the region’s demand. They do not expect that to be the case ultimately, but chose to make this assumption to simplify this initial analysis.
Relative resource availability in a region (i.e., the relative abundance of coal versus natural gas versus renewables, etc.) determines the likelihood of each resource being used to produce H2 in that region. (The levels of each resource will also be affected by the cost of producing the resource, but the report does not factor that in.)
Steam-reforming of natural gas and electrolysis (both centralized and distributed) will be the methods used to produce H2 initially when H2 demand is very low.
Both centralized and distributed production of H2 will be used throughout the time frame of this analysis.
Centralized production will provide the H2 used in metropolitan areas and some non-metropolitan areas, while distributed production (H2 produced at service stations) will meet a large share of non-metropolitan area demand.
Use of natural gas to produce H2 will be phased out completely by 2050.
|Percentage contribution to hydrogen production by each source. Click to enlarge.|
Over time, The report concludes that as demand grows over time, hydrogen will be produced from divergent sources, particularly coal (with carbon sequestration); renewables; and thermochemical water splitting by using advanced, high-temperature nuclear power.
The report does not directly consider the source of electricity for electrolysis, only the direct feedstock or mechanism. For example, coal doesn’t appear as a major source until 2030, despite the coal-generated electricity that will be used in electrolysis in preceding years.
|Estimate of H2 Production in the US in Quadrillion BTU (Quads)|
|Year||Distributed Production||Centralized Production||Total|
|Nat Gas||Elect.||Elect.||Nat Gas||Coal||Biomass||Wind||Solar||Nuclear|
There are two pathways to produce hydrogen from coal:
Central production pathway. Gasification of coal at large, central facilities produces hydrogen. These plants may or may not co-produce electricity or other products, and will be designed to allow capture and ultimately sequestration of carbon dioxide—of which extremely large amounts will be generated.
Alternate production pathway. Fischer-Tropsch fuels produced via coal liquefaction (also a substantial source of greenhouse gases) are transported through the existing petroleum pipeline distribution network to sub-central or distributed locations where they can then be reformed into hydrogen near the end user.
As with production, cost varies by region and by source in this analysis, just as petroleum fuel costs vary today across regions.
By 2050, the researchers project a national hydrogen average cost of $3.68 (current dollars) per gallon equivalent of gasoline. That varies from a high in Alaska of $6.65/GEG to a low of $2.97/GEG for the contiguous Pacific states.
Given current concerns over natural gas availability and pricing in the US, the Argonne assumptions on natural gas pricing for the analysis are too low, absent a dramatic reversal in pricing trends. (The report uses figures ranging from $5.03/mmBTU in 2010 running up to $7.23/mmBTU in 2050. On Wednesday, November 16, prices at the Henry Hub averaged $11.04/mmBTU.)
Substantially higher natural gas prices will likely accelerate the transition to the other feedstocks as well as push up the price of hydrogen in the shorter term.