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Audi in new e-fuels project: synthetic diesel from water, air-captured CO2 and green electricity; “Blue Crude”

Audi is active in the development of CO2-neutral, synthetic fuels; the company already has projects underway with Joule in the US for the development and testing of synthetic ethanol and synthetic diesel (earlier post); has an e-gas project underway in Werlte, Germany (earlier post); and has a new partnership with Global Bioenergies on bio-isooctane (bio-gasoline) (earlier post).

Audi’s latest e-fuels project is participation in a a pilot plant project in Dresden that produces diesel fuel from water, CO2 and green electricity. Audi and project partners including Climeworks and sunfire (earlier post) opened the plant today. The project combines two innovative technologies in this project, which is funded in part by the German Federal Ministry for Education and Research and was preceded by a two-year research and preparation phase: direct capture of CO2 from ambient air and a power‑to‑liquid process for the production of synthetic fuel. Audi is the exclusive partner in the automotive industry.

Other partners in the project consortium include Lufthansa; Fraunhofer ICT; Universität Stuttgart; Forschungszentrum Jülich; GEWI AG; CVT Chemical Engineering; and HGM.

The sunfire plant, which operates according to the “power-to-liquid” (PtL) principle, requires carbon dioxide, water and electricity as raw materials. The carbon dioxide is extracted directly from the ambient air using direct air capture (DAC)—a technology developed by Swiss partner Climeworks.

The Climeworks CO2 capture technology is based on a cyclic adsorption / desorption process on a novel sorbent. During adsorption, atmospheric CO2 is chemically bound to the sorbent’s surface. Once the sorbent is saturated, the CO2 is driven off the sorbent by heating it to 95 °C, thereby delivering high-purity gaseous CO2. The CO2-free sorbent can be re-used for many adsorption/desorption cycles.

Around 90% of the energy demand can be supplied by low-temperature heat; the remaining energy is required in the form of electricity for pumping and control purposes. The patent-pending technology has been developed in collaboration with the Professorship of Renewable Energy Carriers at ETH Zurich. The optimization of the sorbent and scale-up of the sorbent synthesis process is carried out in collaboration with the Swiss Laboratories for Materials Science and Technology (Empa).

In a separate process, a solid oxide electrolysis (SOEC) unit powered with green electricity splits water into hydrogen and oxygen. (sunfire acquired staxera, a developer and manufacturer of SOFC high-temperature fuel cells sited in Dresden in 2011.) The hydrogen is then reacted with the carbon dioxide in two chemical processes conducted at 220 ˚C and a pressure of 25 bar to produce a hydrocarbon liquid called Blue Crude. The process is up to 70% efficient.

Sunfire 2
Sunfire1
Top: Two cartoons of the basic sunfire concept and process. PtL = Power-to-Liquids. Bottom: 3D model of sunfire SOEC (left) and the demo plant (right). Source: sunfire. Click to enlarge.
Sunfire 3

As currently built, the pilot plant on the sunfire grounds in Dresden-Reick can produce approximately 160 liters of Blue Crude per day. Nearly 80% of that can be converted into synthetic diesel. This fuel—Audi e‑diesel—is free of sulfur and aromatics, and features a high cetane number. Its chemical properties allow it to be blended in any ratio with fossil diesel—i.e., it can be used as a drop-in fuel.

The Audi e‑gas plant in Werlte, Lower Saxony, already produces synthetic methane (Audi e‑gas) in a comparable manner; drivers of the Audi A3 Sportback g‑tron can fill up on it using a special fuel card. (Earlier post.) Audi is also conducting joint research into the synthetic manufacture of Audi e‑gasoline with Global Bioenergies. And a joint project with Joule is striving to produce the synthetic fuels Audi e-diesel and Audi e‑ethanol with the help of microorganisms.

With this latest collaboration, Audi said, it and its partners are demonstrating that industrialization of e‑fuels is possible. The pilot plant was officially brought on stream today in the presence of Prof. Dr. Johanna Wanka, German Federal Minister for Education and Research, and Dr. Hagen Seifert, Head of Environmental Assessments, Renewable Energies and New Materials at Audi AG.

Comments

ai_vin

And? Seems to me you're making my point for me. With today's petroleum prices at 3-4 dollars per gallon, and bound to go up in the years to come, even if Joule's price projections are off by 200% they will still be producing E-fuels cheaper than petroleum. And like it not some people can't do without diesel. You think a trucker can go across country on batteries? You think he has space to spare for a LH2 tank? And what about air travel? Joe Sixpack Commuter has the option to buy a battery/fuel cell powered vehicle. The airlines do not.

As I said before: Using clean e-energy to produce dirty diesel liquid fuel instead of clean H2 does seems ridiculous for MOST applications. "Using battery stored energy is the most efficient way, and H2 would be great as a range extender. But there are times when space is at a premium."

Engineer-Poet
With today's petroleum prices at 3-4 dollars per gallon, and bound to go up in the years to come, even if Joule's price projections are off by 200% they will still be producing E-fuels cheaper than petroleum.

Color me doubtful.  Suppose you have an ultimate feed-in tariff as low as 5¢/kWh.  If you can convert CO2 to diesel fuel at 50% energy efficiency, that's 82 kWh input per gallon or $4.10 in electricity alone.  Add capital costs, O&M and taxes and you'll probably triple that, especially if you're carrying all the extra physical plant you need to make full use of peak power flows from wind or solar.

You think a trucker can go across country on batteries?

I think a trucker can go cross-country on rails.  Put up an overhead wire for power, or segmented switchable flush third rail.

And what about air travel?

People used to travel by train, you know.  Those things may be out of style, but they still work.

ai_vin

Trains run on diesel. And yes I know they can be electrified, they SHOULD be electrified and in other countries they are being electrified - but not in North America. Here we lack the political will so trains and trucks will continue to run on diesel for a long time. If only we had a carbon neutral diesel to run them on, oh wait. . .

Color me doubtful. Suppose you have an ultimate feed-in tariff as low as 5¢/kWh. If you can convert CO2 to diesel fuel at 50% energy efficiency, that's 82 kWh input per gallon or $4.10 in electricity alone.

And once again you're ignoring the fact that renewable prices are going down while petroleum prices are going up.

ai_vin

BTW, as we are talking about an Audi plan in Germany, I should point out that in Europe fuel prices are already much higher; http://www.statista.com/statistics/221368/gas-prices-around-the-world/

In Germany gasoline is 8.50 US dallors per gallon and they they DO have electrified trains. People do use them as do freight haulers, but not everybody does - not everybody can. No matter how extensive the rail network is there will always be a need for roads, ships and airports so we will need a carbon neutral fuel to run them on.

Engineer-Poet
Trains run on diesel.

Railroads are giving LNG a try.  They'd be electric already if localities weren't hot to impose property taxes on any improvements; there are rail lines which once had overhead electric power, but the wires were taken down to cut taxable value.

Here we lack the political will so trains and trucks will continue to run on diesel for a long time.

It's a straight financial tradeoff.  LNG is much cheaper than petroleum, and avoids the property-tax issues of electrification.  California may push electrification to move criteria emissions out of populated areas, and if that happens I expect New York and several other states to follow suit.  I doubt there will be many diesel-burning locomotives in N. America in 2024.

you're ignoring the fact that renewable prices are going down while petroleum prices are going up.

The capital and O&M costs of electrochemical plants won't follow the same trend, and you're forgetting that there are major costs involved with transmitting RE over long distances to where it's needed.  The cost is spread over consumers as a whole, which is unfair to them; if it was charged to RE alone as it should, other carbon-free generation might come out cheaper overall and reduce net prices.

In Germany gasoline is 8.50 US dallors per gallon

Most of which is taxes.  Do you think the government is going to give up its tax revenue just because you've changed the energy source?

there will always be a need for roads, ships and airports so we will need a carbon neutral fuel to run them on.

It's probably going to be cheaper to electrify, especially over the long term.  Rail-capable trucks also slash pavement damage; a railway can handle much heavier loads than pavement and it's much cheaper to maintain.  Railbeds can be rebuilt with hand tools.  Add overhead power and your truck only needs something else for the "last mile".  Batteries are up to much of that.

If you've displaced 90% of diesel consumption with electricity, you have about 270 mbbl/d of demand remaining in the USA.  The USA blends close to 1 million bbl/d of ethanol into gasoline, so it's certainly feasible to get rid of petroleum in trucking entirely.

Shipping:  large container ships are practically ideal for nuclear power.  That leaves aircraft.  Air travel only got cheap enough for the masses relatively recently, and I don't see why that is anything but a passing phase.

ai_vin

Yes LNG is a great alternative to diesel and I cheer its use but let's not forget it is still a fossil fuel. Using LNG can reduce greenhouse gas emissions by 15% to 25% on a lifecycle basis compared to diesel vehicles but it's not carbon neutral, using it still leaves us with 75% of the CO2 going into the air.

ai_vin

History has proven CAGW induced Global Warming to be wrong in its temperature raising power. Reality has proven it virtually nonexistent for approaching 20 years now.

History shows that the 10 hottest years on record have all happened since 1998. And "2014 is on track to be one of the hottest, if not the hottest, on record, according to preliminary estimates by the World Meteorological Organization (WMO)." http://www.wmo.int/pages/mediacentre/press_releases/pr_1009_en.html

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