GRA wrote:You seem to be the only one in doubt of what they mean or intend to do, but I'm sure if you find the grant applications they will explain exactly what the processes are. Personally I don't care, as I'm clear in my own mind what end result they're aiming at.
So if you are so clear what is intended, why don't you just write it here. Then we'll all know.
Just in case you are not clear on what the Program Description
says I will copy it here:
DOE wrote:Most liquid fuels used in transportation today are derived from petroleum and burned in internal combustion engines. These energy-dense fuels are currently economical, but they remain partially reliant on imported petroleum and are highly carbon intensive. Alternatives to internal combustion engines, like fuel cells, which convert chemical energy to electricity, have shown promise in vehicle powertrains, but are hindered by inefficiencies in fuel transport and storage. Projects in the Renewable Energy to Fuels Through Utilization of Energy-Dense Liquids (REFUEL) program seek to develop scalable technologies for converting electrical energy from renewable sources into energy-dense carbon-neutral liquid fuels (CNLFs) and back into electricity or hydrogen on demand. REFUEL projects will accelerate the shift to domestically produced transportation fuels, improving American economic and energy security and reducing energy emissions.
Note that the quoted part DIRECTLY excludes hydrogen as an outcome from this project.
Agreed as far as 'transport and storage', but not as final usage, which it seems to directly allow. See below.
Then in the Innovations Needed
DOE wrote:Carbon-neutral liquid fuels as defined by REFUEL are hydrogen-rich and made by converting molecules in the air (nitrogen or carbon dioxide) and hydrogen from water into an energy-carrying liquid using renewable power. While existing fuel-cell electric vehicles (FCEVs) use pure hydrogen as a fuel, the limitations of hydrogen storage and transportation have made it difficult and expensive to build transmission, distribution, and refueling infrastructure for mass adoption of these vehicles. The CNLFs of REFUEL address these challenges by using the infrastructure already in use by traditional liquid fuels. Once the CNLF arrives at its point of use, it can be used to generate electricity in a fuel cell or produce hydrogen on demand, greatly reducing transportation and storage costs. REFUEL projects will aid in the development of energy sources that are readily produced and easily transported, like ammonia, while reducing production costs and environmental impact. Projects will enable new, efficient, scalable and cost-effective energy delivery when and where it is needed.
In this paragraph, hydrogen is specifically excluded BY NAME, as seen in the first bolded section. Both hydrogen AND ammonia are excluded by the second bolded section.
As I said, DOE is misallocating these funds by applying them to projects which directly contradict the objectives which they, themselves, have established.
Thanks for posting all that, and I see that I did somewhat misunderstand the intent of what they're doing, although I agree with the end result. So, AIUI, the intent here isn't solely to come up with renewable liquid fuels, but also (or entirely) to use ammonia (or other) purely for transport and storage, and then convert back (they appear to leave open the possibility of either stationary or on-board conversion) to electricity or H2. I suppose that again brings up the possibility of methanol or some such, with on-board converters. The issues with that were assessed as problematic some years back, but possibly the state of the art has improved now - I haven't been paying attention to methanol for some time.
BTW, I'm now reading the REFUEL Detailed Program Overview, which can be found here (16 pages, lots of tables showing cost comparisons etc.): https://arpa-e.energy.gov/sites/default/files/documents/files/REFUEL_ProgramOverview_FINAL.pdf
I find this on the first page:
The program's overall goal is a competitive total cost (including production, transportation, storage, and conversion) of delivered (source-to-use) energy (e.g. converted to motive power for transportation) as opposed to the primary energy stored in chemical form below $0.3/kWh, the price needed to be competitive with other carbon-free delivery methods, as will be discussed in Section B. The source-to-use energy cost (SUE) is defined here as the sum of the fuel production cost (CF), the cost of transportation from production to the user (CT), the cost of any storage (CS), divided by the conversion efficiency (n) to account for any losses during the conversion steps, and the capital cost of fuel conversion (CC).
Then page 4:
Hydrogen compression and, especially, liquefaction incur additional energy losses (up to 10 and 35%, respectively). In
contrast to liquid H2, which boils-off with a rate of 1 – 4% per day depending on the tank, 10 hydrogen storage and
transportation as a compressed gas has very low losses. Therefore, the latter is a more attractive option for long-term
storage (from days to seasonal). Average cost of hydrogen transportation via a 750 mile long pipeline is estimated to be $1
– 2/kg H2 or $0.03 – 0.06/kWh,11 which is substantially more expensive than pipeline transportation of gasoline (about
$0.025/gal or $0.001/kWh)12 or ammonia ($34/ton per 1000 miles or $0.004/kWh for 750 miles).13
Opportunities for CNLFs
The use of energy-dense liquids, e.g. liquid ammonia or renewable hydrocarbons, with a similar RTE may be an attractive
alternative to H2, due to the absence of or low compression losses. Storage and transportation costs can be even lower if
the carbon-neutral production cost is higher than that of H2. Such CNLFs could be used in appropriately designed fuel
cells. Alternatively, the costs of compression and storage, which is the major cost of the H2 refueling station,14
can be reduced by using with CNLFs as hydrogen carriers and the existing liquid fuel infrastructure technologies. An ANL/TIAX
analysis of hydrogen delivery. using liquid hydrogen carriers with a hydrogen content of 6 – 7 wt.%, showed that the carrier
hydrogen delivery cost will be lower than liquid or compressed (700 bar) hydrogen.15 CNLFs with higher hydrogen content
will be even less costly. Some examples of potential CNLFs are presented in the following section. . . .
Modern Haber-Bosch plants, using hydrogen generation by SMR, release about 1.6 – 1.8 ton CO2 per ton of NH3 of which
only 0.95 ton comes from the SMR process and the rest from heating and pressurization needs.20 Energy consumption for
NH3 production using SMR varies from 7.8 to 10.5 MWh per ton of NH3 (including feedstock, which accounts for 80% of
energy).21 A potentially greener technology option of using hydrogen from water electrolysis requires 9.5 MWh to make 1
metric ton NH3 22 (of which 8.9 MWh comes from hydrogen production, assuming 50.2 kWh/kg H2). 23 Solid-state
electrochemical ammonia synthesis, a possible alternative to the Haber-Bosch process, has potentially lower energy input
and operational pressure and temperature24 thus simplifying the balance of plant, and could be cost competitive as long as
the reaction rate is significantly increased.
Ammonia is in the liquid state below -33 °C or under 15 bar at ambient temperature and has an energy density of 4.25
kWh/L. This value is 35% higher than the energy density of liquid hydrogen (in reality the difference is even larger due to
large energy requirements for H2 liquefaction) and 2.5 times higher than that of hydrogen compressed to 700 bar. It is widely
used as a fertilizer, a refrigerant, and a feedstock for the chemical industry The use of ammonia as a fuel, energy carrier
and hydrogen storage material has also been widely discussed. . . .25,26,27
Looking about a bit I found this graph of NH3 boiling pt vs. pressure: http://www.engineeringtoolbox.com/ammonia-pressure-temperature-d_361.html
which shows that NH3 boils at 120 degrees F. if pressurized to 286.4 in. psia., using a hell of a lot less energy for pressurization than 5 or 10,000 psia for LH2.
Continuing from page 6:
Another example of a nitrogen-based energy-dense fuel is hydrazine hydrate (N2H4·H2O). It is currently produced by
oxidation of ammonia at a large scale (80,000 ton/year globally) and is therefore more expensive than ammonia. However,
it has a high energy density (3.56 kWh/L), is easy to handle (freezing point -51.7 °C, flash point 74 °C) and, if low-cost
synthetic methods are developed, it may fit the technical targets of this FOA. To accomplish wide-scale implementation of
CNLFs, technological advances in both the production and conversion of this fuel would need to be achieved. An example
of a non-toxic substitute for hydrazine with low carbon footprint is carbohydrazide (CH6N4O). Carbohydrazide has been
used as a fuel in a fuel cell with an OCV 1.65V.28
In terms of carbon containing CNLFs, there are numerous examples that would fit the definition, such as hydrocarbon fuels
such as synthetic gasoline or diesel fuel, alcohols, and dimethyl ether., The requirements are that the carbon is directly
taken from the atmosphere or another sustainable CO2 source and that the fuel is produced in a one-pot chemical or
electrochemical process. Current processes for production of synthetic fuels such as Fischer-Tropsch process are multistep,
very capital intensive and eventually not economical. Reducing the process complexity may allow increased efficiency
and lower costs. A viable pathway to generate power (e.g. in fuel cells or ICEs as a drop-in fuel) or hydrogen should be
demonstrated or adopted from literature. In addition, carbon containing CNLFs must have the potential to meet the source-to-use
energy cost targets. . . .
Conversion of CNLFs to electricity
CNLFs may be converted into useful work after transportation and/or storage either directly or indirectly. In this FOA, direct
conversion is defined as delivering the fuel to a fuel cell anode without any prior chemical conversion to generate electricity
directly. Indirect conversion includes fuel that is reformed (cracked) such that hydrogen is stored/delivered at the endpoint
of the transportation and distribution system for further use in fuel cells. . . .
Finally, from the summary on page 8:
The technical approach of the REFUEL program is to develop novel cost- and energy-efficient technologies for generation
of energy-dense liquid fuels from renewable energy, water, and air, and their subsequent conversion to deliverable power
for transportation and distributed generation.
This approach will allow use of existing liquid fuel transportation technologies for transferring renewable energy from remote
or stranded locations to the end-use customer instead of using electricity or hydrogen (schematically represented in Figure
1). Renewable energy such as electricity from solar and wind farms, will be converted to a CNLF (technologies of interest
in Category 1), transported by existing methods, and converted via direct (electrochemical in a fuel cell) or indirect (via
intermediate hydrogen extraction) oxidation at the point of use (technologies of interest in Category 2). Conceptually this
program aims to minimize system level carbon emissions, and electrical transmission and storage losses, while remaining
The target CNLFs can be indefinitely stored in the liquid state under moderate pressure (up to 20 bar) or moderate cooling
(down to -40 °C), can be transported using existing or easily expanded and modified infrastructure, and converted back into
electricity and/or heat. The conversion products (primarily N2, H2O, and CO2) are not captured and are released to the
atmosphere. Fuels containing carbon are acceptable as long as the carbon is taken directly from air or other sustainable
sources such as biomass fermentation and not from fossil fuels. . . .