Scale Model WWII Craft Takes Flight With Fuel From the Sea Concept | Hacker News Reader

Scale Model WWII Craft Takes Flight With Fuel From the Sea Concept

nrl.navy.mil

44 pointsomegaworks21 comments

At best this technology would allow capital ships with nuclear reactors (mostly carriers) to produce hydrocarbon fuel in order to resupply nearby craft. In theory this would help to optimize naval supply chain.

e.g. nuclear carrier fueling jets

I think that's simplistic. It lets any energy source with access to seawater store energy in a very energy-dense medium, eg gasoline. Oceanic wind-turbines, solar panels, nuclear generators on the ocean, etc. Certainly more useful short-term for the navy, but could definitely be extended to civilian uses.

I guess the real question is efficiency.

Yes, but given the huge demand for energy everywhere there is absolutely no point wasting so much energy converting it except in locations where/when transporting a energy-dense medium to is difficult but highly valuable.

IE The middle of the ocean during a war.

The cost for this energy is $3-$6/gallon according to the US Navy's estimate. I get about $9/gallon if you include the costs of solar power provisioning. Or $126 - $378/bbl.

That's not cheap, but it's a damned sight better than pretty much any biofuel alternative, which runs about $1000/bbl.

And fuel is essential for transportation. Some transport can be liberated -- you can run passenger cars on batteries (for a price). Within cities, buses and even delivery vehicles can be electrified (possibly with on-board batteries for short off-grid excursions). Rail absolutely can be electrified.

But a lot of uses cannot be.

It's difficult to run power cords across oceans (though you might be able to electrify some barge and river traffic). Especially if you want to tap into them at sea. An electrified marine cargo business isn't an option. Your primary alternatives are sail power, biofuel (including possibly pelletized wood ships, an existing proposal), or electrically-generated synfuels as here.

Airplanes handle electric cords even worse than boats do. There are numerous airline industry initiatives looking at biofuels, but Boeing's "biggest breakthrough there is" bet really doesn't pan out. Unless you want to cover _all_ of Oklahoma and Kansas, as well as parts of Louisiana, Texas, New Mexico, Colorado, Nebraska, and Missouri, just to supply fuel to the aviation industry.

Worldwide, shipping and aviation account for about 5% each of total petroleum consumption.

Or you could create the fuel. Yes, shipping prices, airfares, and air cargo rates would increase. But you'd still have them.

And while that's expensive by the standards of fossil fuel extraction (with oil at an unusually low price of ~$75/bbl right now), the cost of solar generation keeps falling and seemingly has further to fall, whereas the costs of fossil fuel extraction seem set to keep rising - both because of the increasing difficulties of access and because of increasing pressure to account for externalities, whether at the point of production (like wastewater injection) or consumption (CO2 and soot pollution). We should probably be looking at $126/bbl (at $3/gal) for fossil fuel so as to include the refining costs that would be obviated by this technology (and which have unaccounted-for externalities of their own).

I don't see what's not to like here. You could even use relatively inefficient solar harvester arrays anchored offshore to do most of the processing, and in the event of a spill it would still be substantially cleaner and easier to manage than crude.

I'm generally pessimistic about the future. This is among the most interesting and positive things I've run across in years.

There are still limitations, as I noted. Solar costs are falling, but if you look at total installed system costs remain high. EROEI and other metrics of net positive energy are perilously close to minimums necessary to sustain civilization.

I'm not a fan of marine-based installations just based on weathering and corrosion. But a number of industrially-large plants would work. For the U.S., a single facility 4.5 km x 4.5 km x 10 m high would suffice based on USNRL's scaling factors. Split that among a number of regional facilities and you've got distributed capacity at a large industrial scale.

It's the solar collection that's the big and pricey part of this.

Thanks for your very interesting analysis here and above - I will certainly dig through your Reddit posts on the subject as I want to learn more about where the manufacturing barriers would be and what sort of private partnerships the Navy would enter into over the projected 7-10 year deployment timeframe, not least because I'm struck by the fact that the basic technology must be unencumbered by patents to the extent that it originates with the government.

While agreeing that solar collection is no slamdunk (see for example this story about the SoCal Ivanpah plant running at only half the hoped-for capacity at present: http://www.mercurynews.com/business/ci_26954832/huge-mojave-...) I'm personally OK with nuclear, geothermal and hydroelectric dams as potential power sources notwithstanding their own externalities.

The part that's likely not to be unencumbered is the CO2 extraction itself. But otherwise, yes, much of this is public-domain tech.

I'm on the fence regarding nuclear for at least two main reasons: safety (particularly the hard-to-quantify-of-guarantee long-term safety), and fuel availability. The picture on both strikes me as less than clear. Near term, perhaps useful as a bridge fuel.

Geothermal is actually pretty awesome, but much more profoundly limited than most people suspect (tide and wave power are also overestimated -- the San Francisco Bay, for example, represents less total tidal power than the bay region uses in electricity, and only a small fraction of that potential could be extracted). Enhanced geothermal (basically, injection wells) have proven expensive and low-benefit, see Australia's Habanero project and its challenges.

Hot, wet-field geo though is proven, and a high-yield resource in Iceland, Japan, the Philippines, Kenya, New Zealand, the US, and a few other regions. In developing regions (particularly Kenya) it could dramatically increase total electrical generation capacity.

Hydro is largely built out and has environmental issues, though it also works quite well.

It's a sticky problem.

Reprocessing carbon to run in combustion, jet and turbine engines already in existence could be huge for the environment in the long run.

The two best alternatives we have right now are battery or hydrogen powered engines. Both have major hurdles still to cross. Both rely on centralized power, have density issues, and have huge R&D & consumer cost/acceptance issues.

Centralize power generation, use a smart grid to efficiently transfer energy to coastal towns, create efficient pipelines to distribute hydrocarbon fuel, use existing gasoline/diesel infrastructure in cities/towns to serve consumers using their existing vehicles.

Further, this technology promises much cleaner, less sulfurous gasoline. Current gasoline is filled with all sorts of impurities, and needs to be significantly distilled to get the long-chain organic compounds that are needed for efficiency; This tech seems to create long-chain compounds from the base materials of carbon and hydrogen, meaning less impurities and less distillation.

That's the theory.

It's possible that in processing the volumes of seawater necessary to provide carbon to this process you'd introduce other impurities. But with a well-regulated process, it does seem to offer the option of a cleaner gasoline / diesel than we've got now.

I've been looking into the research on this process for a few months. In a world with a lot of bleak news on energy fronts, it offers some promise -- not of "free energy" (it isn't), but of a sustainable, abundant, predictable, carbon-neutral liquid fuel provisioning option.

First: liquid hydrocarbon fuels are hugely useful for a number of characteristics.

They're very energy dense, by both weight and volume. They've over ten times the energy storage density of batteries, and while they have lower energy density by unit weight than hydrogen, have over seven times the density by volume with vastly fewer handling constraints. They're easily handled (no high pressures, low temperatures, corrosion, embrittlement, or other issues). They're generally really safe -- many liquid hydrocarbons won't explode unless specifically induced to do so. They're a drop-in replacement for existing fossil fuels. They could be blended with these, and can utilize the same processing, transport, and utilization infrastructure. Engines would not have to be modified. At the same time, for those who see efficiencies in electric drives, they're amenable to hybrid-drive technologies. And we've got well over a century of expertise in utilizing them.

For transportation, liquid hydrocarbons are very hard to beat, and for certain modes, all but essential, especially heavy land cargo, marine shipping, and air travel.

The research that the US Naval Research Lab is conducting is based on over 50 years of work on the concept, with the first studies undertaken by nuclear physicist Meyer Steinberg at the Brookhaven National Laboratory in 1964. Steinberg continued his research through the 1990s, with further work at M.I.T. under Michael J. Driscoll and more recently as USNRL (who peculiarly fail to cite the earlier research -- it's rather like an evolutionary biologist failing to credit Darwin). Steinberg's work generally considered nuclear power as the electricity source, though any generating option could be substituted. More recent research considers nuclear, solar, and OTEC, an ocean thermal power system.

The basic concept was suggested by M. King Hubbert, the petroleum geologist who predicted peak oil in the 1950s, in a 1962 report (though he suggested mining carbon from limestone).

In terms of process, there are two very-well understood processes operating at industrial scale presently, hydrogen electrolysis and Fischer Tropsch synthesis. The third stage is where most research is focused: on finding means to sequester carbon from seawater. A small fraction is present as dissolved CO2, but most (about 96%) is in the form of dissolved carbonate and bicarbonate.

Since carbon is being drawn from the biosphere (seawater), it's overall carbon neutral, though it might tend to bias balance slightly toward the atmosphere as compared to the oceans. If run in excess of human energy needs (a very expensive proposition), it could sequester additional carbon from the atmosphere.

The primary energy cost is in the electrolysis, which returns hydrogen with about 60% of the energy capacity as the input electricity -- so your conversion costs you energy. Fischer Tropsch processing is exothermic (more energy is released than consumed). Energy usage of the CO2 separation phase is comparatively low, much of it is in the water handling -- you've got to move a lot of seawater to get the carbon necessary. I suspect overall efficiency will be roughly 50%.

Though the Navy research is looking at this for their own purposes, it could just as well be used for civilian purposes. The 100,000 gallon/day capacity seen for a carrier task force would be roughly appropriate for a city of 100,000. My own cost estimates, including solar power provisioning, are higher than the Navy's, about $9/gallon. But that would be a stable price going forward -- with a renewable liquid fuels source, there are no oil embargoes, supply shocks, or imports.

At a national scale for the United States, supplying 20 million barrels/day, you'd require 2TW of power -- a solar collection region about 180 miles on a side. That's quite large, but as compared with biofuel-based alternatives, downright reasonable -- most plant-based fuel proposals if scaled out would require a sizeable fraction, or several multiples, of total US land area to provide an equivalent of present petroleum usage.

On the "bad news" front: the fact that research has been conducted in this area for 50 years without significant implementation suggests that there may be engineering or other challenges which are frustrating broader application. Or it could be that fossil fuel prices have simply been too low to allow larger-scale demonstrations.

I've explored a few other aspects of this in a series of reddit posts covering the USNRL's work and other historical background.

Search on "fischer tropsch": http://www.reddit.com/r/dredmorbius/search?q=fischer+tropsch...

USNRL research and papers: http://www.reddit.com/r/dredmorbius/comments/22k71x/us_navy_...

BNL/MIT history and papers: http://www.reddit.com/r/dredmorbius/comments/28nqoz/electric...

M. King Hubbert connection: http://www.reddit.com/r/dredmorbius/comments/298a4l/seawater...

And for comparison, limitations on biofuel potential:

http://www.reddit.com/r/dredmorbius/comments/28k1w5/prospect...

http://www.reddit.com/r/dredmorbius/comments/2cvap7/the_intr...

I guess the output of the fuel after use is still greenhouse gas, but would this reduce net CO2 emissions?

It doesn't seem it would. The CO2 is from seawater; burning releases it into the air. Since seawater has many times the density of CO2 as air, it would definitely be a net greenhouse gas process.

However comparing making liquid fuel this way, with drilling refining and shipping gasoline, it may be a great improvement!

The surface ocean and atmosphere exchange CO2 freely. So as long as the electricity input is carbon neutral, the process is carbon neutral.

i.e. it doesn't matter if you take CO2 out of the surface ocean or the atmosphere. Both will reduce the concentration of CO2 in the atmosphere.

http://en.wikipedia.org/wiki/Carbon_cycle

A major source of the oceanic CO2 is the atmosphere http://en.wikipedia.org/wiki/Ocean_acidification. It's not perfect but could be much better than burning dinosaurs.

The carbon in the fuel comes from CO2 which is captured out of sea water.

The problem with fossil fuels is that they transfer old carbon which used to be stored underground into the atmosphere.

This process only uses carbon that is already part of the active carbon cycle, so it is carbon neutral as long as the electricity source is.

Yeah, that's what I was thinking. It's not eliminating carbon in the atmosphere, but it's avoiding adding more from fossils.

It can't get worse.

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