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Audi unveils e-gas project: synthetic methane from the methanation of green hydrogen; series production of CNG models in 2013 powered by e-gas

Tcng
Audi A3 TCNG for e-gas project. Click to enlarge.

Starting in 2013, Audi will begin series production of TCNG models whose engines—derived from TFSI units—will be powered by e-gas: synthetic methane produced via the methanation of hydrogen produced by electrolysis using renewable electricity. Audi’s newly unveiled e-gas project is a component of achieving its goal of “Audi balanced mobility”—i.e., achieving a neutral CO2 balance across the entire mobility chain.

Audi says that the e-gas project, which after three years of research is now entering the practical phase, is a cornerstone of its mission to set up an entire portfolio of sustainable sources of energy. Audi will supply three sources of green energy in the scope of the e-gas project: electricity, hydrogen and methane gas. Respectively, each one is suitable for a very different type of drive concept: for electric cars, fuel-cell vehicles and CNG vehicles. The e-gas project consists of two main components:

  • Audi is contributing to the construction of offshore North Sea wind turbines which will generate clean power,that is then fed into the public power grid. Audi wants to use green power to produce and also operate its electric-drive e-tron models in the future.

  • A new plant, the e-gas project’s second component, will use the remaining green power to produce hydrogen by means of electrolysis. This source of energy, generated in a climate-friendly manner, can be used to power fuel-cell vehicles in the medium-term. Audi will also combine hydrogen with CO2 in an additional methanation step to produce methane. Although this methane is also known as synthetic natural gas, the company refers to it as Audi e-gas.

    Audi notes that methanation is particularly advantageous in that the reaction occurs with the aid of CO2, which consequently is not discharged into the atmosphere. This results in a completely closed CO2 cycle.

Audi says that its e-gas project provides an answer to the question as to how green power can be efficiently stored, irrespective of location. If there are strong sea winds, for instance, then surplus power supplies can be converted to e-gas and stored in the largest available energy-storage system: the public gas network. If necessary, this energy can flow from the gas network back to the power grid at any time.

Along with our project partners, AUDI AG is realizing a method which puts CO2-neutral mobility within reach. Our technology has the potential to give new direction to the discussion on expanding renewable sources of energy. We ourselves are taking the initiative and are complementing electric mobility with an equally eco-friendly concept for long distances.

—Michael Dick, Member of the Board of Management for Technical Development

Audi has completed the research phase of the e-gas project and will take the second step in mid-2011: investing several tens of millions of euros in the construction of an industrial facility. Audi will kick off this large-scale energy project together with its project partners: SolarFuel GmbH from Stuttgart; the Centre for Solar Energy and Hydrogen Research (ZSW), also based in Stuttgart; the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) in Kassel, Germany; and EWE Energie AG.

Wind turbines are the first significant component of the Audi e-gas project. During the project’s first phase, four large power plants at an offshore wind park in the North Sea are being financed by Audi and a regional power-supply company. Rated at 3.6 MW each, these four turbines are to supply some 53 GWh of electricity annually.

Concerning the use of wind power in Germany, offshore wind-power stations currently play a minor role. Located far from the coastline, they harness wind averaging 30 km/h (19 mph) to produce about 40% more energy than onshore stations.

The project’s second large component is the e-gas plant, which will produce hydrogen and methane on an industrial scale. Ground is scheduled to be broken in Werlte, Germany in July 2011. The e-gas plant is connected to a waste-biogas plant, which supplies the concentrated CO2 necessary for methanation and which would otherwise pollute the atmosphere. The plant will annually produce some 1,000 metric tons of e-gas while consuming 2,800 metric tons of CO2.

The e-gas plant has two main components: an electrolyzer and a methanation unit. There is also piping technology, tanks, open-loop and closed-loop control electronics, and compressors for feeding e-gas into the natural-gas network. In January 2011, a lab facility with an output of 25 kW was set up for testing purposes.

The electrolyzer runs on green electricity. Aided by polymer electrolyte membranes, the electrolyzer splits water into its components: hydrogen (H2) and oxygen (O2). Hydrogen will not be used directly for fuel cell vehicles during the project’s first phase; instead, after being separated and dried, it is placed into a storage tank and then the methanation unit.

Here, the hydrogen is combined with carbon dioxide (CO2) to create methane (CH4) as per the Sabatier reaction; water (H2O) forms as a by-product.

Even during this initial phase of the e-gas project, the electricity generated by wind power and the methane produced at the plant will suffice for 2,500 motor vehicles in total. Some of the wind-generated electricity would be enough to manufacture 1,000 units of the A1 e-tron and propel them 10,000 km (6,200 miles) per year. An additional share will be fed into the grid; surpluses within the power grid would thus benefit the e-gas plant, too, Audi says.

By means of the e-gas generated via renewable energy, 1,500 units of the A3 TCNG could each be driven 15,000 km (9,300 miles) annually, with 150 metric tons of e-gas remaining for the public gas network. As needed, this gas could also flow back. All in all, that represents a big boost to the power grid and equates to far more than 30,000,000 climate-neutral kilometers (18,700,000 miles) driven every year.

In terms of the well-to-wheel analysis, a compact natural-gas car powered by e-gas emits fewer than 30 grams of CO2 per kilometer (48.28 g/mile), including all emissions created during construction of the wind turbines and the e-gas plant. Only electric vehicles which are directly supplied with wind-generated electricity perform even better: they emit under 4 g/km (6.44 g/mile). However, Audi notes a drawback in the overall energy picture regarding vehicle production: a lot of energy is needed to manufacture the batteries.

Audi says that its e-gas project is capable of solving several pressing problems faced by the sustainable energy-supply industry all at once. In the process chain, clean power, hydrogen and methane are produced: three key sources of energy for future mobility. In the medium-term, this technology has the potential to establish a highly flexible power-supply infrastructure for electricity, heating and motor vehicles which is based entirely on renewable energies; in addition, the respective percentages of the three sources of energy can be adjusted as required.

Renewable energies already account for 17% of electricity generated in Germany; renewable sources of energy are forecast to make up 77% of Germany’s overall electricity consumption by the year 2050.

The Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) was commissioned to conduct a study by WindEnergie, a German association. According to the study, wind power could be harnessed to realistically generate some 390 terawatt hours (TWh) of energy; this would have satisfied 64.7 percent of Germany’s overall electricity consumption in 2010 (603 TWh). Overall output in the computational model amounts to 198 gigawatts (GW).

The production of electricity via wind and sun, however, is subject to natural fluctuations and the necessary storage capacity is currently very low. Pumped-storage power plants are capable only of short-term storage: during an emergency in Germany, they could supply power for all of an hour. All other solutions, such as compressed-air energy storage plants, are similarly very limited regarding capacity and period of storage.

Audi argues methanation of hydrogen using renewable energy helps solve this problem: the power grid is linked to the underground gas network, which can store surplus power supplies for months. The gas network has a potential capacity of 217 TWh, in contrast to the power grid’s storage capacity of just 0.04 TWh. The latter’s transport capacity, moreover, is just one tenth of that of the gas network.

Energy can be conveyed from the gas network—perhaps by means of gas-fired power plants or, in a decentralized manner, in block-type thermal power stations—back to the power grid at any time. New, decentralized cogeneration power plants can boost efficiency even more. In addition, methane is also suitable for the supplying of gas to private residences or providing high-temperature process heat.

The efficiency ratio of the e-gas pilot plant—from wind turbine to methane gas—is about 54%. If the dissipated heat is also used, this value is considerably higher still. The aim is to achieve an efficiency ratio above 60% in the future. Audi says that the potential to store large quantities of energy—made possible by pairing electricity with gas on the one hand as well as wind energy and solar energy on the other—can “truly invigorate” the expansion of renewable sources of energy. The Audi e-gas project can easily be replicated in any country with an existing natural-gas network.

The Audi A3 TCNG. The Audi A3 TCNG can run on the e-gas which Audi produces in the methanation unit. Via the “balanced cycle method”—similar to the purchasing of green power—A3 TCNG owners should be able to fuel their vehicles with wind energy starting in 2013. When a driver refuels with e-gas, the corresponding amount of renewable energy required to produce this e-gas is fed into the grid.

The high octane rating of approx. 130 RON for natural gas, biomethane and also for e-gas facilitates a high compression ratio in the turbo engine, which ensures high efficiency. The Audi A3 TCNG also boasts a bivalent configuration: if the natural-gas tanks run empty and there is no CNG station nearby, the vehicle can run on conventional gasoline with no drop in performance.

Comments

DaveD

Wow.

"synthetic methane produced via the methanation of hydrogen produced by electrolysis using renewable electricity"

This has to be the DUMBEST frigging thing I've read in years. Let's take something that is already under fire for being inefficient, H2, and then use that as the input of yet another series of conversions....and call it green.

And we wonder why people laugh at us for being a bunch of treehugging, green morons.

Davemart

This sounds more like an exercise in picking up Government subsidies to me.
The 53GWh they reckon they are going to get means a flow of about 6MWe, which is 41% capacity for the 4*3.6MW turbines they are building.
Actual output from the Dutch off-shore field comes to about 33% capacity:
http://dww.wmc.eu/pdf/2a-02%20DWW%20October%202010-R01%20Kouwenhoven.pdf

It all smacks of the usual renewables tradition of underestimating cost, overestimating output and getting the Government to pick up the bill to me.

Davemart

I'd love to know what the round trip efficiency of using electricity from burning the syngas to balance the grid is.
Not that that should be much of a worry, as it will be so expensive that no-one would be able to afford it.

SJC

This reminds me of BMW cars that burned hydrogen with a slight twist. Just take the wind turbine electricity and charge an EV/PHEV and be done with it.

dahcredyns

I think the big picture is being overlooked a bit in these comments.

Storing renewable electricity is still a very serious issue, which is a big focus of this effort. Yes, hydrogen into methane seems nonsensical, but it provides a more fungible long term energy framework - a worthy pursuit in my opinion based on the lab science demonstrating the very real possibility of both bio hydrogen and methane, for instance.

Likewise, batteries are almost certainly decades away from providing a cost-effective solution for high mileage driving, minimally. Besides, mining and shipping lithium and or battery packs across the globe results in many extra costs that could significantly increase with demand, as so often happens to commodities.

Ultimately even converting wind power into hydrogen into methane might still be a more cost-effective way of storing electricity than in batteries, especially if supplemented by bio-versions of hydrogen and methane that might one day replace such methanation. Long term, fuel cells at power plants could be the key to even more cost-effective electricity for plug-in cars. Furthermore such an approach is built on embracing legacy infrastructure systems - something Accenture has pointed as being critical for developed countries.

And, seriously, it's ironic that we call this a grab for tax incentives when the battery, solar and wind industries would today be dead if not for massive tax expenditures. Moreover, look at the battery studies coming out of places like Argonne. There are huge obstacles to overcome and they are going to take time, even Argonne's 2025 projections will still be expensive based on today's energy terms.

Ultimately, I think the science proves absolutely conclusively that there is no home run solution to replacing oil any time soon. That requires holistic thinking that can take advantage of overlaps between even divergent technologies. This kind of convergence will drive the the near and mid term energy futures. Furthermore, the science also suggests that there are huge breakthroughs that could rewrite the book on energy in ways we simply cannot predict today.

wintermane2000

Ok sillies.. I see you didnt bother to READ it and just did your spaz to h2 blather as always...

Note...

The e-gas plant is connected to a waste-biogas plant, which supplies the concentrated CO2 necessary for methanation and which would otherwise pollute the atmosphere. The plant will annually produce some 1,000 metric tons of e-gas while consuming 2,800 metric tons of CO

Also note.. even with all the factors accounted for the resultant car they will produce only emmits 30 g/km of co2 and yes that includes ALL the well to wheels...

Its powering electric cars fuel cell cars and its creating sythentic nat gas for more cars or for heating or whatever else is needed.

So next time read the artcle before posting... it makes you look like a 3 year old.

Davemart

wintermane:
Perhaps you should try reading the comments before critiquing them.
I don't believe I for one referred to the hydrogen production, but the syngas and their plans to use it.

ejj

With the e-gas process as proposed, Audi is also capitalizing on the demonization of fracking for natural gas. If e-gas takes off, look for the "horrors" of fracking to continue to be espoused everywhere, in Europe especially.

SJC

waste-biogas plant

That term is not defined, it can mean anything from a brewery to a chicken farm.

Davemart

@SJC:
Germany has quite extensive biogas production. There was some kerfuffle recently because the utilities do not allow it in the general gas network, I am not sure hoe it panned out.
It works pretty well, but is a lot more expensive than natural gas, at least at the prices American's are used to paying.

DaveD

Wintermane,

You're assuming all those wonderful things you describe are the most efficient use of the resources and that is crux of the problem.

The only thing they're doing that makes sense is the methanation as an energy storage mechanism. I don't see the evidence that they have some huge source of excess energy here that needs to be stored so they are solving a non-existent problem at this site.

Now if they want to argue that this essentially makes a large "battery" for storing excess grid energy and that it's more cost effective than pumping water up hill for later use in hydro-power, etc, then make that argument and apply it to a situation where there is large amounts of spurious energy that needs to be stored for the grid.

This is just greenwashing the way they are doing this stuff and is not the most efficient use of the energy available.

SJC

Biogas as in methane from landfill or water treatment? If that is the case they have methane already.

wintermane2000

I dont have to assume anything dave. They spell it out quite clearly. They want all three types of VEHICLES for dealing with all types of needs and they also want to deal with heating needs. Being able to basicaly plug your windfarms into the gas grid and not just the power grid is a very good idea... assuming the plant can run well enough to actualy do it. As for biogas.. most likely after they clean the methsna from the biogas they have alot of concentrated co2 as a waste product... This converts it into methane.

Davemart

Some rough calculations of the energy efficiency of this lunacy are here:
http://www.energyfromthorium.com/forum/viewtopic.php?f=39&t=3065

It works out to about 12.5% for the automobile part, and perhaps 20% for providing back up for their wind power.
Costs of the electricity for back up are in the range of 5-15 times present costs.

Davemart

Taking the efficiency of conversion of electricity to hydrogen at 70%, methanation at 70% and combustion engine efficiency at 25% you get an overall efficiency of 12.5%
If we take a price of $0.10kwh for electricity from wind, actually it is way more, that comes to $1.22kwh equivalent for the liquid fuel.
At 36kwh/US gallon, that is about $44/gallon to run the car, not counting the equipment needed
Travel should be limited.

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