Synthetic Fuels with Advanced Engines or Hydrogen and Fuel Cells as a Medium-Term Solution?
11 September 2006
The transportation sector may find that synthetic fuels combined with next-generation advanced compression-ignition engines are more cost- and energy-efficient than using refinery-produced hydrogen to power fuel-cell vehicles in the medium term, suggests Thomas Rostrup-Nielsen of Haldor Topsoe. Topsoe is one of the world’s leading catalyst companies.
He made the remarks during a plenary address to a symposium on hydrogen production at the 232nd National Meeting of the American Chemical Society in San Francisco.
Although the long-term goal is the development of systems for the cost-effective production of hydrogen from renewable resources, he noted, in the present—and likely into the medium-term—steam reforming of hydrocarbons is still the most cost- and energy-efficient process even with carbon capture and sequestration factored in.
Carbon capture and sequestration basically doubles the cost of hydrogen produced via steam methane reforming, according to figures Rostrup-Nielsen showed—and its cost still comes in below other hydrogen production methods at this point in their development.
Although the financial costs are much higher, hydrogen production from non-fossil sources offers much lower overall GHG emissions.
Advances in the large-scale refinery production of hydrogen via steam reforming using gaseous hydrocarbon feedstocks (methane, refinery off-gases, LPG, and so on) have become increasingly efficient, with current processes requiring about 2.98 Gcal of energy for each 1,000 normal cubic meters of hydrogen produced.
Theoretically, the lowest consumption required—from stoichiometry—would be about 2.81 Gcal (when using liquefied hydrogen). Thus, current advanced reforming processes consume about 6% more energy thant the theoretical minimum, according to Rostrup-Nielsen.
As a result, he said, the cost of hydrogen at the refinery gate is approximately equivalent to that of gasoline. It’s the other factors downstream from the refinery—such as transportation and distribution—that push the cost of hydrogen to 3-4 times that of gasoline.
While distributed reforming to produce hydrogen—at a filling station, for example—could address some of those additional costs, it also would open up other challenges. Carbon capture and sequestration would be difficult to perform economically with distributed production, Rostrup-Nielsen noted. Even assuming the carbon capture was cost-effective, there then would arise the issue of what to do with the carbon dioxide and how to transport it.
Yet even with the efficiency of centralized hydrogen production, synthetic fuels combined with coming advanced combustion engines and powertrains could end up with a well-to-wheels energy efficiency comparable to that of using hydrogen produced via steam reforming in a refinery and a fuel cell, he said.
With advances in existing engine technologies, and using existing infrastructure, one could consider whether it is a good idea in the interim to go [for distributed production of hydrogen]. Use the money saved [by opting for synfuels and advanced engines] for developing hydrogen production from renewable energy sources. It’s an interesting set of tradeoffs.
It is important that one does not pursue hydrogen as a matter of religion but as an educated decision.—Thomas Rostrup-Nielsen
I think the key thing is to focus on the goal (transportation with a very low environmental impact) rather than the means (hydrogen or whatever). If we set our sights on developing an H2 fuel cell car, rather than a very low emissions car, we are missing the point and spending billions and many years in the process.
So define the goal clearly and let the technologies slug it out.
Posted by: mahonj | 11 September 2006 at 03:25 PM
Nice to see some of the Scientists are coming around to where we have been for years.
Posted by: Lucas | 11 September 2006 at 03:47 PM
He was a brave man trying to convert true believers. It could be pointed out he mainly covered well-to-tank issues. On top of that are issues of engine cost and reliability which deliver the double whammy to FCVs.
Posted by: Aussie | 11 September 2006 at 09:28 PM
Mr. Nielsen forgot to consider an ICE-electric hybrid with direct fuel injection capable of both methane and hydrogen. Using methane and hydrogen directly as produced from pyrolysis and gasification of biomass is more efficient than the extra energy and effort in producing synthetic liquid fuel via F-T synthesis from the syngas output of gasification of coal or biomass. The CO2 captured from steam reformation of hydrocarbon can be used in high-temp solid oxide electrolysis cells for the production of methane from solar energy. Without CO2 input, high temp electrolysis will produce only H2. H2 is good for short-range local use up to ~120mi per fillup using ~15-20 gallon tank at 300 bars. For long range, fill up the same tank with methane at 300 bars to enjoy a range of ~400 miles. H2 and methane is far cleaner for the local air quality than liquid hydrocarbon, the latter is also carcinogenic and is bad for asthmatics.
Posted by: Roger Pham | 11 September 2006 at 11:25 PM
"It is important that one does not pursue hydrogen as a matter of religion but as an educated decision."
Posted by: Nick | 11 September 2006 at 11:38 PM
I still think batteries can do a better job. If hiper capacitor can be manufactured than everything else (energy storage) is obsolete. But this is not going to happen, because oil companies want something to "fill up". Hydrogen is one solution.
Remember: I am 100% sure that hiper capacitor won't be comercialized, never ever... if the oposite happens I am the happyest man on the planet...
Posted by: Skrivo | 12 September 2006 at 12:29 AM
If a hiper capacitor is possible to be build it will be build by someone. The oil companies have a limited control over RD. If you had a magic solution for the transportation problem it would be adopted for sure by some car constructor.
Posted by: MH | 12 September 2006 at 02:58 AM
MH - I have been trying to give away a "magic" approach for years. Nobody seems to be able to grasp the idea.
Google William Lucas Jones hybrid.
Finally, Seimens and Mitsubshi are toying with part of it, but the rest is just beyond comprehension. Not much point in adding the next step until these are absorbed. I want to talk about how to make a safe, lightweight auto body using EPP, Spectra and Carbon.
Posted by: Lucas | 12 September 2006 at 09:26 AM
I googled William Lucas Jones hybrid. Interesting that you chose a direct drive permanent magnet motor that makes regenerative braking impossible. Personally I think electrical regenerative braking isn't worth the added mechanical and/or electronic complexity.
Posted by: tom deplume | 12 September 2006 at 05:34 PM
Siemens also agrees with you.
Posted by: Lucas | 12 September 2006 at 05:53 PM