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Published on November 24th, 2014 | by Guest Contributor


Power-to-Liquids Demonstration Plant Opens In Dresden

November 24th, 2014 by  

Originally published on EnergyPost.
By Karel Beckman

A Power-to-Liquids (PtL) demonstration rig, which is the first of its kind in the world, was officially inaugurated on 14 November by Dresden-based sunfire GmbH. The ceremony was attended by German Federal Minister of Education and Research Johanna Wanka, Board Member Pieter Koolen of venture capitalist Bilfinger (in which Total and EDF participate) as well as a number of other high-ranking representatives from the worlds of politics, industry and research.

sunfire-power-to-liquids-demonstration-plant-250x166The new rig uses sunfire’s PtL technology to transform water and CO2 to high-purity synthetic fuels (petrol, diesel, kerosene) with the aid of renewable electricity. So-called PtL fuels – also known as “e-fuels” – can be used in pure form or as an admixture in combination with conventional fuels, and are recognized as an environmentally friendly, resource-saving alternative which contributes to the fulfilment of greenhouse gas quotas.

High-temperature steam electrolysis

The PtL technology is built around the solid oxide electrolysis cells (SOECs) developed by the cleantech firm as part of the eponymous BMBF research project SUNFIRE. Step 1 of the PtL process sees the SOECs used to convert electrical energy to chemical energy. Hydrogen is generated using steam rather than liquid water.

Step 2 – the reverse water-gas shift reaction – is again innovative, and involves the use of the hydrogen (H2) yielded by the steam electrolysis step to reduce carbon dioxide (CO2) to carbon monoxide (CO) for the third and final step: Fischer-Tropsch Synthesis. This step sees the carbon monoxide and additional hydrogen (in the form of renewable synthesis gas) converted to petrol, diesel, kerosene and other base products for the chemicals industry (e.g. waxes). The feeding of the heat released during synthesis back into the process ensures a high degree of system efficiency (70 per cent).

Proof of technical feasibility at industrial scale

The cost of building the PtL demonstration rig was within the seven-digit range, with development costs also incurred at the various consortium members. Half of the overall sum invested corresponds with the public funding received from the Federal Ministry of Education and Research. The rig’s capacity for CO2 recycling stands at 3.2 tonnes per day, and once brought into commission it will produce up to a barrel of fuel per day. Commercialization is dependent on further technological development and regulatory factors and scheduled for 2016.

“The sunfire process reduces CO2 emissions and reduces our dependency on oil”, said Federal Minister Johanna Wanka at the inauguration. “It therefore represents an opportunity to protect our climate, save resources and at the same time promote a new technology which promises to deliver economic growth. Over and above that, one huge benefit of PtL fuels is that existing infrastructure such as filling stations, pipelines and motors can continue to be used without modification. This paves the way for sustainable mobility based on renewable energies.”

sunfire-Power-to-Liquids-Prozess_72dpi-1024x433“This rig enables us to prove technical feasibility on an industrial scale”, commented sunfire CTO Christian von Olshausen. “It is now a matter of regulatory factors falling into place in a way which gives investors a sufficient level of planning reliability. Once that has occurred it will be possible to commence the step-by-step substitution of fossil fuels. If we want to achieve fuel autonomy in the long term, we need to get started today.”

Dr. Karl Ludwig Kley, Managing Director of Bilfinger Venture Capital said: “In the case of sunfire – a start-up in an unconventional industrial sector – it is interesting to note that the technology moves in tandem with the market. As a strategic investor, Bilfinger is able to offer not only technical know-how which feeds into the planning and construction of industrial facilities, but also access to potential customers. In particular, a cooperation has been set up between Bilfinger EMS and sunfire. Both partners have already begun to jointly bring PtL technology to the market.”

Reprinted with permission.

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  • Kevin McKinney

    I’m wondering about scale and economic efficiency: ‘seven figures’ for the prototype rig, and ‘one barrel a day’? Proof of concept, sure, but it seems like a big distance from real practicality.

    • Ulenspiegel

      You miss the point. P2G or P2L are required, if at all, in 25 years or later. It does of course make sense to test various approaches today in the technicum scale.

      • Kevin McKinney

        I don’t think so. Consider the quote from the Minister in the story:

        “The sunfire process reduces CO2 emissions and reduces our dependency on oil”, said Federal Minister Johanna Wanka at the inauguration. “It therefore represents an opportunity to protect our climate, save resources and at the same time promote a new technology which promises to deliver economic growth. Over and above that, one huge benefit of PtL fuels is that existing infrastructure such as filling stations, pipelines and motors can continue to be used without modification. This paves the way for sustainable mobility based on renewable energies.”

        These are not goals for 20-25 years out.

  • JamesWimberley

    Any news of the ingenious German plan to upgrade biodigesters with synthetic hydrogen? The basic chemistry is simple: plant materials like cellulose have a ratio of carbon to hydrogen twice as high as that of methane, so natural fermentation stops with half the carbon still solid. Add hydrogen and you can double the methane yield. Methane is a much better feedstock for synfuels than hydrogen.

    For the moment, these German initiatives are markers laid down for Putin. We synthesised fuel in WWII, and can do it again if you force us to.

  • Michael G

    With the rapidly dropping price of solar panels we have to think in terms other than efficiency. If in 20 years energy costs so little it is essentially free then portability, ease of use, storage become paramount while efficiency is immaterial. This could be the solution to a lot of problems. The one advantage of ICE over EV is energy density. Petrol is about 100 times more energy dense than batteries, which is probably why no one answered my question a few days ago of “are you planning on running battle cruisers and tanks on batteries?” There are applications that need that density, efficiency be da*ned. That’s why the Germans synthesized oil from coal. You can’t run airplanes and tanks on coal.


    My question is where do they get the CO2? If at some point it is out of fossil fuels then we still have the main problem of releasing long buried C into the air.

    • Larmion

      The problem is that you present a false dilemma: liquid fuel or battery storage. There are other alternatives:

      a) Hydrogen can be produced more efficiently than liquid fuels. Even without developing a storage and distribution infrastructure, a significant amount of hydrogen can be put to good use by injecting it in the natural gas network (up to 5-10% substitution).

      b) As road vehicles, which can be powered by batteries, gradually stop using liquid fuels, more biofuels are freed up for ships and airplanes. Concurrently, second generation biofuels (cellulosic ethanol from woody biomass and grasses) and perhaps algae biofuels will increase the supply massively.

      c) Ships don’t really care much for energy density, hence their use for bunker fuel. They use whatever’s cheap, not what’s most dense. That means at least some ships could use CNG sourced from waste (either landfill or AD) or even batteries if cheap enough. They are also prime candidates for using hydrogen.

      You’re right that it’s not about efficiency. It’s mainly about cost – which tends to follow from efficiency ceteris paribus. The only sustainable and cost effective biofuel is ethanol as of 2014 and that’s unlikely to change in the future (and even that is questionable: only cellulosic ethanol and sugar cane ethanol are sustainable, the corn ethanol in use in the US has little environmental merit).

    • johnBas5

      This article includes the taking of CO2 from the air.

      • Joseph Dubeau

        No, from what I read on their website. It needs a supply of CO2.

      • Jenny Sommer

        No…from a steel plant..purified steel waste streams (Thyssen-Krupp).

    • JamesWimberley

      Has anybody built a battlecruiser since HMS Hood?

      • Shane 2

        The Germans got rid of that battlecruiser in a few minutes.

    • Joseph Dubeau
  • Larmion

    Yikes. Why?

    Fischer-Tropsch is a hugely inefficient process (50% is considered pretty decent). Why not stick with hydrogen if you’re already making it? Every extra conversion step inevitably reduces efficiency. The hydrogen can easily be injected into the natural grid, as demonstrated already in Germany.

    • Karn

      Perhaps because petrol etc is easy to store and can be used by most cars ?
      The US navy has a similar project to manufacture aviation fuel .

      • Joseph Dubeau

        renewable jet fuel.

    • Bob_Wallace

      Do you see a better long term storage option than hydrogen?

      I recognize that it could work for Germany because they already have the ability to store. On a more general level, for those countries that will need to build storage, do you see a better “product”?

      • Larmion

        Hydrogen can be injected into the natural gas grid, thereby bypassing storage. Current natural gas based instrastructure can handle roughly 5% injection of hydrogen without needing to change anything.

        5% of Germany’s natural gas demand is equivalent to an enormous amount of excess electricity, far more than is produced today. And in the more distant future? Well, batteries are coming down in cost.

        • Bob_Wallace

          I’m asking if there’s a better option than hydrogen if a country doesn’t have a natural gas distribution system where they can store the H2.

          • Fancyfree

            I thought hydrogen was very difficult and expensive to store long term because the ultra small atom leaks thru absolutely any tank material…whereas if you make oil/petrol you can store and transport it easily for very long periods?

          • Larmion

            Yes, but if you inject it into the gas network it doesn’t get stored. It’s carried directly to a power plant, home or other consumer and then burned. You avoid storage.

          • Bob_Wallace

            If we’re considering H2 for deep backup then we’re talking long term storage.

            eta: There’s no reason to convert electricity to H2, send it to a power plant, and turn it back into electricity.

          • Larmion

            Yes, but why would you use it for that in a world where pumped hydro, batteries and dispatchable power sources like biomass, hydro and geothermal offer greater efficiency and lower cost?

            Power to gas is a viable method for eliminating short bursts of excess power. Using it as deep backup is unlikely to ever become economical, especially since it would mean building a dedicated hydrogen infrastructure. That might be viable if the FCEV takes off and the cost thus can be shared between the transport and electricity sector, but that’s not very likely at the moment…

          • Bob_Wallace

            I don’t know why. I’m trying to learn.

            There are many people on the web talking about H2 for energy storage. I’m trying to get a grasp on the options and their costs.

            H2 is very lossy, but if storage is free that’s in its favor.

            PuHS is affordable but takes some effort to get permitted in many cases.

            Batteries look to be reaching affordable for 1 or 2 days storage but not for 7 or more.

            Biomass is a possibility, especially if we convert existing paid off coal plants and avoid the capex costs.

            CAES works but has some problems.

            There’s a guy who wants to tow train loads of rocks up an incline.

            What I’m asking is are there other options you know about that aren’t commonly discussed? What about ammonia? Is it easier/cheaper to produce/store than hydrogen?

          • Jenny Sommer

            Ammonia will be a product of the sunfire process.
            I don’t get the H2 economy either.
            E>H2>E Roundtrip efficiency with SOFC (60%) would be 54% or a little higher with combined heat and power.

            Would be ok if you need the heat. Maybe massive winter windspills.

            But then it would still be better to use the power for dispatchable load like charging EVs, home appliances and hot water/heating.

            Saw that train idea. I don’t know. I still like the hydraulic hydro rock storage idea.

          • Bob_Wallace

            It will all come down to economics.

            Here’s the basis (I think) against which long term storage has to be compared. Gas peaker plants in California sell their power, on average, for $0.49/kWh. If storage can’t beat that price then gas will be burned.

            I took the projected cost of EOS batteries, $160/kWh and looked at their annual cost based on 6%, 20 year financing. They’d need to earn $13.80 per year to break even. (They are rated 10,000 cycles and 30 years.)

            If they cycle once per day (75% efficient) then including input electricity at 4 cents per kWh the cost for electricity stored for <=24 hours would be 9 cents.

            If they cycle ~50 times a year then the cost would be about 32 cents. Also cheaper than peaker average. But by the time we get to four cycles per year the the EOS batteries would cost $4/kWh and gas peakers would win in the market.

            To get gas plants totally off our grids we need some way to store power long term for less money or some way to cut loads during the most problematic times.

            Perhaps Germany needs to put pulp mills, aluminum smelters and other high demand industry on vacation in January. They already, or did, close down their shipyards for a few weeks in the coldest weather. The US may need to pay some industry to schedule a few weeks of vacation for the hottest part of summer.

          • Matt

            If you are not talking about storing the H2/gas mix. Then this option would only make sense if you have already closed all your gas power plants. And this mix is being used for cooking and heating. Or maybe I should say, I’m a little lost on the purpose of this.

          • Bob_Wallace

            That’s part of my questioning. The US NG distribution leaks methane like a sieve.

          • Steve Grinwis

            To be fair: Leaking hydrogen is far less damaging, I think. I think it will just slowly react with oxygen and form water as it comes across hot things, like lightening strikes, or cosmic rays… Unclear….

            I’m kinda hoping we head towards a system where people get heat from ground or air source heat pumps. That’s something I’m going to be looking at in my next house.

          • Larmion

            The question is: where would that be? Most countries have at least a rudimentary gas network supplying a few power stations.

            There’s also the very simple fact that countries without gas networks tend to be poor. Can a country too poor for a gas pipeline afford to waste a massive amount of electricity on producing some liquid fuel? They’d be better served with some manner of grid level storage and biofuels.

    • Steve Grinwis

      My suspicion is that they’re looking forward to the future, instead of looking to make an immediate impact now.

      I agree though, better immediate gains could be made right now injecting the H2 to the natural gas grid. You can go up to about 10% H2 without issue. Beyond that the appliances have to be rated for it, which is somewhat more challenging to deal with. The cause of this limitation is hydrogen embrittlement.


    • johnBas5

      Storing transportation fuels is much easier and hence in large amounts cheaper.
      The added benefit of products that can be used immediately really makes a difference.

    • Ulenspiegel

      The amount of hydrogen that can be injected into the NG pipeline/storage system is limited to 2% without larger changes in Germany.

      A P2G or P2L approach has only value as long term-storage. The hardware are expensive chemical plants that require high FLH, therefore, are not suitable for the reduction of short term electricity peaks, this issue can better be handled by batteries.

      A combination of biomass fermantation, that results in a mixture of methane and carbon dioxide, and electrolysis, which provides hydrogen, seems the better approach. Bacteria convert the hydrogen and carbon dioxide at room temperatur and moderate pressure into methane.

      One can speculate whether a additional injection of CO2 and H2 is possible, i.e. the bacteria and biomass are only the catalyst.

    • Jenny Sommer

      The whole process is 70% efficient from electricity to fuel.
      Methane will be one of the products from sunfires process.
      The goal is to produce Methane, Methanol (>fuel) and Ammonia from purified steel waste streams (Thyssen-Krupp).
      Methane or H2 can obviously go into the ng-grid.
      Stadtgas contained around 51% H2.
      Another idea is to reverse the process using SOFCs.
      E>H2>E Roundtrip efficiency with SOFC (60%) would be 54% or a little higer with combined heat and power.

      Sunfire says 2022 for the first commercial plant.

  • Steve Grinwis

    How does it consume 3.2 tonnes of CO2, and only produce one barrel of oil a day??

    Pretty sure a barrel of oil is only 55 gallons.. a long way from 3.2 tonnes…

    • Oil4AsphaltOnly

      hydrocarbons are mostly hydrogen and carbon atoms. 3.2 tons of CO2 only has ~800lbs of carbon in it. And hydrogen itself doesn’t weigh much. It’s still a ways off from the 400lbs a barrel of oil would way, but not [edit] drastically so.

      • Steve Grinwis

        C has an atomic weight of 12, O has an atomic weight of 16, but there’s two of them. So 12 / 44ths of the 6400 lbs would be carbon, or around 1800 lbs, not 800… And that’s 4x the weight of the barrel of oil, and we haven’t added any hydrogen back in…

        • Oil4AsphaltOnly

          oops. forgot about the ton -> lbs conversion. You’re right. it’s 4x off.

          • Dan Hue

            +1 for admitting your mistake. We’re so used to people digging themselves into a hole to China rather than doing what you did 🙂

          • Oil4AsphaltOnly

            What can I say? To err is human, and I embrace my humanity!

            I’ve seen those comments. Some of them are ideological in nature and the “digger” is having a hard time with the mindset change. *1* But the ones browbeating them to prove that the diggers are wrong aren’t helping push the discussion forward either, as they are equally intransigent in their dogma. The good commenters acknowledge when others have a valid point and I wish to be amongst them.

            *1* My mother wants to buy a new camry even though she commutes only 10 miles per day and has no plans to drive further than 30 miles and will most likely stop driving in 10 years. But she refuses to consider a leaf. Very infuriating. Maybe if toyota carried a BEV camry then she’d consider it?!

    • Joseph Dubeau

      gallons is volume and tonnes is weight.

      It depends on the density of the fluid.

      • Steve Grinwis

        I’m aware that units of volume and weight don’t equate, but the weight of a drum of oil is known. It’s about 250 lbs… That’s a long way from 6400 lbs. 😀

        • Joseph Dubeau

          Now you on to something, the question I have is where did all the oxygen go?

          • takin up space

            <> dunno man <> but here’s some more fuel for the process.

        • Joseph Dubeau

          Take a look at the diagram
          The process produces a O2 output stream.


          • Steve Grinwis

            No matter how you add it up, 1800 lbs of carbon doesn’t fit in a barrel that weighs 250 lbs, regardless of where the oxygen goes…

          • Joseph Dubeau

            I don’t know where you get those numbers from.
            They produce SynGas not raw crude oil.
            There are no details on their process.

          • Steve Grinwis

            From the article you are currently commenting on:

            “The rig’s capacity for CO2 recycling stands at 3.2 tonnes per day, and once brought into commission it will produce up to a barrel of fuel per day.”

    • Jenny Sommer

      It uses 3.2 tonnes per tonne of produced fuel.
      They can produce any fuel. Oxymethylenether sounds interesting to me. It’s a high oxygen diesel like fuel that burns very clean.

      E>H2 efficiency 90%
      E>fuel efficiency 70%
      E>H2>E Roundtrip efficiency with SOFC (60%) would be 54% or a little higer with combined heat and power.

      The goal is to produce Methane, Methanol (>fuel) and Ammonia from purified steel waste streams (Thyssen-Krupp) that include Co2, Co and H2.

      It would still be better to find non polluting ways for the cement and steel industry than to recycle the CO2.

      Here is a German FAZ article that has more detail.

      There is also something about cost there.

      • Steve Grinwis

        Interstesting information that was missing from the posted article.

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