NOT a Game Changer

By Rud Istvan

ctm asked what I thought about the 7/31/2019 Forbes article by James Conca headed, “Net Zero Natural Gas Plant Game Changer.” My quick answer after reading the piece was, not much. He asked me to write up a WUWT guest post. I decided to research it rather than rely on Forbes; turns out Forbes omitted ‘fun’ facts, and got others just wrong.

Background

Carbon Capture and Sequestration (CCS) has been a green dream for a long time. (There is a now slightly dated review in essay Clean Coal in ebook Blowing Smoke.) There are two very fundamental problems.

1. CC. It is very expensive and technically difficult. There is today exactly one power plant in the world with partial CC, SaskPower’s Boundary Dam project in Canada, which began operation in the fall of 2014 at a CC only cost of $1.5 billion. The plan was to convert coal fired generating unit #3 to CC, capturing 800,000 metric tons of CO2 annually to sell for tertiary oil recovery in Saskatchewan’s nearby Weyburn oil field. For the two most recent complete years (2017-18) the average Unit 3 uptime was only 70% (severe maintenance problems), while the CC parasitic electrical load has run about 30% rather than the planned 25%. On July 10, 2018 SaskPower announced it would not be expanding CC to units 1 and 2 as originally planned.

2. S. There is exactly one US sequestration only demonstration, the ADM/DOE project in Decatur, Illinois. The plan was to sequester CO2 from ADM’s Decatur ethanol operations (no CC problem) in the brine filled Mt. Simon sandstone formation 7000 feet below Decatur. The demonstration project cost $208 million, with DOE contributing $141 million. The goal was 1 million tons sequestered over 3 years, at an injection rate of ~1000tpd. The goal was never reached, because the injected CO2 reacted with the brine to form mineralization that slowly plugged the sandstone injection sites, necessitating ever more injection wells. ADM announced in 2018 that it was delaying its more ambitious next phase despite the neat little provision (26 USC 45Q) tucked into the February 2018 tax bill providing an inflation indexed $20/CCS CO2 ton tax credit (tertiary oil recovery deemed S).

Forbes

The Forbes article describes a zero net emissions 25MWe natural gas fired electricity generating demonstration plant in La Porte, Texas (near Houston). It uses a new ‘Allam’ cycle using ‘oxyfuel and supercritical CO2’, where the effective turbine working fluid is CO2. The idea is to burn the natural gas in a high pressure ‘so supercritical CO2’ pure oxygen ‘so oxyfuel’ environment, thereby eliminating the CC problem. The demonstration plans to sell the resulting pure CO2 either to industry or for Texas tertiary oil recovery. Startup was last month. Hence Forbes.

For those interested in details, the ‘Allam’ cycle was invented by North Carolina startup Net Power. They provide the usual overly optimistic stuff (examples follow); a March 2019 presentation is available via www.NetPower.com. I obtained my 33 page copy from University of North Carolina Institute for the Environment, where the greens are as excited as Forbes.

Combusting natural gas with pure oxygen requires an air separation unit (ASU). Sure enough, the demonstration plant has its own cryogenic ASU. At any real volume, ASU is always cryogenic, meaning big compressors, heat exchanger fans, and lots of electricity. Since N2 boiling point is -195.8C while O2 boiling point is -218.8C, for every liter of LOx you must also make about four liters of liquid nitrogen—which is why liquid nitrogen is cheap. Air Liquide and Linde sell prepackaged containerized ASU to industry, hospitals, and the like. They also build massive custom plants to supply bulk tonnage liquid oxygen (LOx) to big users like the basic oxygen furnaces in modern steel mills. As a benchmark, an Air Liquide unit designed to support aircraft operations at 2 tons/day uses 3600KWh per LOx ton according to the device spec.

The Net Power materials say the 25MWe demonstration plant costs $140 million. That implies the capacity costs $5600/KW. A standard CCGT (capacity about 600-800MW) costs between $2000 and $2500/KW. Even allowing that this only a first demonstrator, Net Power has a long way to go on capital cost, AND has to find a lot of high value CO2 sales. Sequestration alone suggests the economics don’t work.

The demonstration plant is 50MWth and 25MWe. (Forbes confused thermal and electrical capacity). That means it runs 50% thermal efficiency. Standard CCGT runs 61% at full load, and still 58% at 40% load (and shuts down below 40%). That means the Allam cycle has a 20% fuel cost disadvantage, perhaps made up by selling CO2.

The demonstration plant is 25MWe, but Net Power page 7 says the parasitic ASU load is planned to be 29%, in the ballpark of Boundary Dam. So its salable electrical output is only 17MW, meaning its true capital cost is $8235/KW, NOT $5600/KW as Net Power implied (but did not say).

Finally, through ‘magical’ financial calculations on presentation page 22, Net Power says the 26 USC 45Q $20/ton CCS tax credit is really worth about $40/ton to them. Except a tax credit is only useful if you have taxable income, which Net Power doesn’t. I leave grokking their math to the reader, because I can’t.

Thus the title of this guest post: NOT a Game Changer.

HT/ColA ~ctm

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70 thoughts on “NOT a Game Changer

  1. And as it is vaporware, all costs are estimated (how?).
    And it is very fuel inefficient, so it would be both very sensitive to gas prices and subsidies for CO2 capture, with the CO2 capture payments depending on the government, so Hillary Clinton losing upset some business plans regarding energy.
    Forbes used to do the numbers, or is my memory mistaken? I was never a regular reader.

    • CO2 is an acid, carbonic acid, H2CO3, when dissolved in water. Geologically active. Makes limestone caves, for example. Also biologically active. Critical for ongoing acid/base balance in our bodies, for example.

      Wonder if our climate change catastrophe friends, who don’t mind slaughtering hundreds of thousands of birds annually with windmills all for a “good cause”, have demanded full environmental analysis of pumping industrial levels of this weak acid into the ground.

      • CO2 is not acid , it has no hydrogen so no one is “pumping weak acid into the ground”. If you want to attack something it helps to make accurate claims.

        Beyond that you have a good point. Injecting a gas which will react with ground water to make a weak acid will result in “ground acidification” . I can well imagine that in 10 years the enviros will be doing yet another U-turn and start campaigning against CCS because it is “poisoning the Earth.”

        • You need not wait for 10 years, gogmatic eco-mentalists already dislike CCS because it potentially offers a lifeline to coal, oil and gas exploitation, even if punative thin air taxation were to make it prohibitively expensive to burn and exhaust to atmosphere. Not only that, but it’s evil big oil who has the means and expertise to execute the storage side of the equation and gang green won’t approve anything that profits an evil oil company.
          With respect to the effect of carbonic acid on the geological storage, that might be of concern were the storage unit a carbonate reservoir, but typically a sandstone aquifers are chosen for storage and in that case, the eventual effect of adding liquid CO2 is to ‘fix’ the CO2 in situ via mineralisation and the resulting carbonate cementing of the sand grains will reduce the permeability of your aquifer making subsequent migration and leakage more unlikely. The affect of carbonic acid on the materials used for the injection well are of more concern than ‘making caves’.
          What the professional enviro’s are most concerned with is leakage to surface (either from the geological storage unit via faults, from a failure in the injection well or old oil/gas wells nearby, or during transport at surface). A surface leak is where the CO2 has real detrimental affects on the neighbouring critters.

          • You might search “Lake Nyos” for what can happen if a sequestration scheme blows a gasket. A natural “sequestration” of volcanic CO2 overturned, releasing a massive volume of gas which asphyxiated 1800 people in 1986.

          • “Rich Davis August 11, 2019 at 5:47 am
            As kwinterkorn stated Greg, in water CO2 forms carbonic acid. You are the one mistaken.”

            Really!?
            So, you get acid burns deep in your lungs right up through your nasal system every time you exhale?

            Greg is correct in stating that CO₂ is not an acid.

            After CO₂ dissolves in water, a small fraction of the dissolved CO₂ reacts with water to form carbonic acid.
            The carbon atom of CO₂ is electron poor. Water’s (H₂O) electron rich oxygen atom donates electrons to CO₂’s carbon.
            CO₂ (aqueous) + H₂O H₂CO₃ (aqueous) forming carbonic acid.

            Atmosphere’s 0.04% CO₂ trace gas dissolving in water following Henry’s law and inversely to temperature; with only a small fraction of the dissolved CO₂ reacts with water forming carbonic acid at water/atmosphere CO₂ equilibrium.

            CO₂ is not an acid. Conflating CO₂ and the small fraction of carbonic acid forming after CO₂ dissolves in water is incorrect.

          • CO2 is anhydrous carbonic acid, ATheoK. Geological brines are acidified when CO2 is injected into them.

            If you like, CO2 itself can be called a Lewis Acid. Lewis acids consist of electron-poor complexes, typically metal complexes, that when dissolved bond to water molecules and then release a proton. Dissolved in water Lewis acids, and CO2, produce a Brønstead Acid.

            kwinterkorn and Rich Davis are correct.

            Carbonic acid, H2CO3, is actually pretty strong in and of itself. The reason we don’t get acid burns when we exhale is that most of dissolved CO2 stays as CO2 (nearly 99%). So, the solution is only weakly acidified.

        • CO2 is anhydrous carbonic acid. kwinterkorn is correct.

          When CO2 is injected into deep wells, it typically encounters brine phases (salty water). Dissolution produces carbonic acid, bicarbonate, and carbonates along with a fair amount of dissolved CO2 itself. [CO2 + H2O H2CO3, but the equilibrium lays to the left]

          The pH of the brine is lowered by the injected carbonic acid, and reactions with the geologic minerals occur. These often produce insoluble carbonates that end up blocking diffusion pores of the brine aquifer.

          Metals such as iron are also mobilized. And because the clay and sandstone metals are released, the mineral silicates also dissolve into the brine.

          The chemistry is complicated because of the high pressures and temperatures, and also because the specific mix of minerals and metals can vary with the location.

          Looking at the literature, people have just been getting around to the basic experiments to figure out what happens when CO2 is injected into deep wells. It’s clear that carbon sequestration is being promoted without any detailed understanding of the geochemical consequences. Here, for example.

        • CO2 is a Lewis acid. The Lewis definition does not require the presence of a proton. That requirement is for the Bronstead-Lowry definition of an acid.

        • As a gas, it isn’t an acid. But CO2 Will react with the subsurface strata and become a weak acid.

  2. There’s also Petra Nova in Fort Bend County Texas…

    https://wattsupwiththat.com/2017/04/18/clean-coal-carbon-capture-and-enhanced-oil-recovery/

    https://wattsupwiththat.com/2018/03/08/clean-coal-carbon-capture-and-enhanced-oil-recovery-part-deux/


    At $50/bbl, the economics of Petra Nova are, at best, marginal… But it clearly works.

    If the Net Zero facility in La Porte Texas can actually economically convert 97% of its CO2 emissions to fuel… It will be a “game-changer”… A big if. The 45Q tax credit is fully transferable for CCUS purposes… meaning that it can be “sold” to investors, like the Wind and Solar ITC.

    https://www.natlawreview.com/article/implementation-recent-amendments-to-45q-carbon-sequestration-tax-credit

      • Petra Nova didn’t become operational until 2017. The only politics involved was a DOE grant covering 19% of the cost and the 45Q tax credit… Both of which have overwhelming bipartisan support.

        The fact is that it significantly reduced emissions, didn’t affect electricity output, and immediately boosted oil production in West Ranch oil field from about 100 to over 3,000 bbl/d.

        • David Middleton August 11, 2019 at 5:03 am

          Petra Nova didn’t become operational until 2017. The only politics involved was a DOE grant covering 19% of the cost and the 45Q tax credit… Both of which have overwhelming bipartisan support.

          Don’t know about “bipartisan”, but neither the tax credit nor the DOE grant of my taxpayer dollars have MY support …

          What is it with you green supporters, that you always want to use my money to build your green castles in the sky? GET YOUR HANDS OFF MY WALLET, and when your fantasy is actually economically viable, it will be enthusiastically accepted in the market.

          Sorry for the shouting, but I don’t like people stealing from me to fund their eco-dreams …

          w.

          • I think there’s value beyond immediate costs and profits, for developing new, proof of concept projects, … like the Manhattan Project or those nuclear powered ice core extracting stations. Also, I’m kind of surprised to see you implying that David Middleton is a green supporter, considering his impressive body of work here.

        • Petra Nova didn’t affect output? The CCS on unit 8 is a 240 MW unit on a 654 MW capacity unit. That’s at least 26% power reduction from the unit 8. Or it’s 37% of the nameplate output. You cannot add a natural gas generator to a coal unit and ignore the output of the NG unit.

          Petra Nova’s hope for breaking even is an oil field and $50/bbl. Are you going to build all those plants next oil field needing EOR?

    • Excellent point , David. When I read, “There is today exactly one power plant in the world with partial CC, SaskPower’s Boundary Dam…” I immediately thought of Petra Nova. It is arguably the largest and most successful CO2 capture plant in the world, with an equivalent of 240 MW, far surpassing Boundary Dam.

  3. Rud,

    Thank you for looking into this. The Allam cycle as reported a couple of months ago seemed to be an interesting concept. Other than the press releases and Wikipedia was as far as I got. Comparing CCGT with the Allam cycle doesn’t look like The Allam cycle is much use unless you have a use/need for lots of liquid nitrogen and CO2. I gave consideration to using wind mills to generate/separate oxygen and hydrogen through electrolysis. Hey, seems we’re stuck with a bunch of ’em so maybe they could be put to some good use.

  4. Carbon Capture and Sequestration (CCS) has been a green dream for a long time. … There are two very fundamental problems.

    1. CC. It is very expensive and technically difficult.

    Besides that it is stupid.

    • Indeed. They could just give all that money to me and I would guarantee them the same effect on climate.

      • Yes, I’d take it for sure and guarantee the same “climate change” impact. Since CO2 HAS NO “climate change” impact, “sequestering” it isn’t going to do squat.

    • CCS is industrial equivalent of trying to shovel sh*t up hill. It is an obviously stupid endevour.

      The only real aim of CCS is to make coal fired power stations totally uneconomical so they go out of business and cease to exist. This was “legislated” in Obama’s Clean Power Plan.

      Thanks to Rud Istvan for digging into the facts and numbers on this. It is useful to see just how stupid this looks economically as well as technically.

  5. Carbon sequestration made easy:

    1: Mine coal
    2: Burn it
    3: Plant trees
    4: Make paper from the trees
    5: Pulp waste paper
    6: Pack it into coal mines using the same tech used for “rammed earth” construction.

    • Even easier. Thatch roofed houses with Phragmites common / water reed. Nearly ton for ton carbon. There are thousand year old thatched roofs extant. Phragmites is of course an invasive that’s been here 6,000 years and is still just wasted, rotting, releasing carbon back to the environment,

      Ignorance IS confirmation bias.

  6. Great post. I am glad to see some numbers on the energy cost of capturing the carbon dioxide from the combustion gasses. I always knew it would be bad, good to see the quantitative info.

    Tech note:
    Oxygen BP – 90.2 K, -183 C
    Nitrogen BP – 77.3 K, -196 C
    If you leave a flask of liquid nitrogen out, liquid oxygen will condense out on top and create an unexpected hazard. Nitrogen has a lower BP, not higher.

  7. Awww, why do you guys always have to spoil a feel-good climate-control story by presenting detailed idea-squelshing facts?

  8. California says it will stop using electricity generated in Utah from coal and plans to use emptied out salt mines to store compressed air to run turbines as a storage device for wind and solar power that would otherwise be wasted. Has anyone seen a real engineering evaluation of such an endeavor? Sounds like poppycock to me.

    • It is not good. In short, you compress a gas and it get hotter. Let it sit and it cools off and depressurizes somewhat. So you just lost the energy that went into heating the gas. This is a thermodynamic effect and cannot be avoided.
      Compare with Pumped Hydro. Pumped Hydro has no thermodynamic issue, and so is at the theoretical limit of 100%. In practice, the full turn around is ~80% due to all the usual suspects, pumps, generators, turbulent flow.
      Now compare compressed gasses. All the usual losses, the same as pumped hydro plus the thermodynamic losses from compressive heating and static cooling. This is why nobody uses it for anything. Not experimental cars, not niche applications, nothing. A few toys, that is about it.

      • I have heard of a proposal to use wind turbines to compress air into what is essentially an LNG storage sphere and then use that to ‘turbo-charge’ a natural gas fueled combustion turbine. Since the compressor end of a combustion turbine uses about a third of the power generated by the turbine end, this hybrid arrangement allows the CT to run with the compressor end decoupled or de-clutched, and makes the CT about 40% more efficient. Essentially, it allows the energy captured by wind to be dispatchable, which is one of the great shortcomings of wind and solar. Only seen this on paper , but it does seem to require relatively higher gas prices to make it economically viable

        • What they do with the stored energy is essentially irrelevant. They are still just storing energy as a compressed gas. As others point out, this just doesn’t work economically. It’s one of the toys TonyL mentions.

      • They ‘Store’ the thermal energy that’s lost during compression so they can add it back in during decompression.

        Store it how? Where? For how long? They were talking about storing energy for weeks or months, even ‘seasonal’. Frankly, if it was possible to store that much heat energy for that long without serious losses we wouldn’t NEED compressed air storage.

        This sounds like something that would work for storing energy for a few hours at most. Like TonyL said, a few Toys.

        ~¿~

    • As far as I know Californium doesn’t really have any “salt mines” to speak of, and if that is there intent, they are wackier than I thought. Salt deposits in dry lake beds and in salt ponds along the Pacific coast but no underground salt mines.

  9. Some mineralization may be possible with carbonic acid dissolving natural carbonate (Ca-Mg-Fe) cement in the largely quartz sandstone and redepositing it with distance and reduced pressure as it passes along the formation.

    However, my money is on the unintended “fracking” of the sandstone which would generate silica fines that would plug off the formation with distance slowing rates and limiting storage. Were I asked as a problem solver, I would advise advancing pipe and actually fracking the formation properly using good frack sand for a couple of thousand feet to prop open fractures before the injection of CO2. This is essentially reversing the standard fracking process. I think it would work technically, but the costs may need creative green accounting methods.

    • Gary P

      I was going to write exactly the same thing. If it is getting blocked, frack it and carry on.

      • Oh, Oh, can I be the one to tell the Greens that the solution to their problem is Fracking? That sound even funnier then telling them the only way they’re getting carbon free electricity economically is by embracing Nuclear.

        ^¿^

  10. In the case of qualified carbon oxide captured using carbon
    capture equipment which is originally placed in service at a
    qualified facility before DOE, if you’re the person that captures
    and physically or contractually ensures the disposal, utilization,
    or use as a tertiary injectant of this qualified carbon oxide, the
    credit is attributable to you unless you elect to allow the credit
    to the person that disposes of the qualified carbon oxide,
    utilizes the qualified carbon oxide, or uses the qualified carbon
    oxide as a tertiary injectant. If you make this election, the credit
    won’t be allowed to you.
    The credit is attributable to you in the case of qualified
    carbon oxide captured using carbon capture equipment that is
    originally placed in service at a qualified facility on or after DOE,
    if you’re the person that owns the carbon capture equipment
    and physically or contractually ensures the disposal, utilization,
    or use as a tertiary injectant of this qualified carbon oxide. For
    purposes of section 45Q, for any tax year in which such facility
    is an applicable facility (a facility placed in service before DOE
    and for which no taxpayer claimed a section 45Q credit for any
    tax year ending before DOE) that captures not less than 500,000
    metric tons of qualified carbon oxide during the tax year, you
    can elect to have the facility, and any carbon capture equipment
    placed in service at the facility, treated as if it was placed in
    service on DOE.

    IRS form 8933. What does it mean? I don’t know. But credit transfers happen with renewables at times. A non-profit may be able to sell or transfer them for instance.

    In any case, the credit is a subsidy. Money falls out of the sky. It makes no sense. It goes to subsidy farmers I suppose. I forgive Forbes. They make some sense. I cite them a lot.

    • Ragnaar

      Subsidies related to CO2 come from carbon trading. In order to qualify for carbon trading anything larger than a “small” project has to demonstrate “additionality” according to rules of the Clean Development Mechanism of the UNFCCC. This is part of the Kyoto Protocol. Additionality means the project cannot get carbon offset credits if it financially viable without them. It must require the “addition.” It is only when the “addition” of the carbon trading money makes it financially viable that trading of the carbon reduction is permitted.

      So the challenge is how to make any CCS project appear unviable, but that adding the offset money will make it profitable. If a technology really worked and would be profitable through, for example CO2 sales, it won’t get any trading subsidy. No offset support, carry on because it is profitable and companies will do it anyway.

      The Kyoto Protocol ends in a few months. The replacement is the Paris Accord (believe it or not) and there is are freshened requirements in Article 6.2 and 6.4 for all projects to a) get a new baseline calculation and b) demonstrate additionality.

      So a totally unviable technology will not be supported because the carbon price is too low to make it work financially, and it means people press for a very high carbon trading price like $40 a ton.

      Elizabeth May, head of Canada’s Green Party is pushing for an ever-increasing price for carbon so that eventually even the most hopelessly uneconomic CCS systems will be “made viable”. That is the other extreme. I am pretty sure she doesn’t know what she is talking about.

      Imagine trying to sell a project as viable if the CCX price of 5 cents a ton CO2e was added, and without it it was unviable!

      Now try to find a technology that needs the EU’s $5 a ton to “make it financially viable” while simultaneously claiming that without the $5 no one would invest in it.

      On top of all that, and completely out of the news, is the rebellion by poor countries including Brazil, that the carbon trading pie be sliced in a way that guarantees a big funding pot for them, something they didn’t get under the Kyoto Protocol. The refusal of Brazil, in particular, in June to accept less, caused the failure of the climate talks. The press didn’t mention it.

      There will be a big push in the US the week of 27 Sept to get the nation to declare a climate emergency, ahead of the penultimate meeting meeting in late November just before COP25. Declaring a climate emergency is hoped to provide public pressure on poor countries to give up their demand for a slice of the funding pie, almost all of which which has been going to projects in the rich countries.

      Watch that space. Brazil and others are refusing to be given the crumbs they received from the Kyoto Protocol arrangement. Meanwhile the rich countries are planning to sop up all the funds using crazy-expensive CCS technologies that are unaffordable to the poor. They want almost all of a much bigger subsidy pie.

      The MSM are totally sequestering the catastrophe in June when the issue of allocating a guaranteed portion of the carbon market funding to developing countries could not be resolved. Brazil wants, among other things, all existing CDM projects to be converted to Article 6 projects, however the new rules demand (expensive) re-baselining and demonstrated additionality. The current CDM projects will be cut off in most cases.

      In short, the Paris Accord seeks to entrench the status quo: rich countries getting carbon trading profits and subsidies fed by funds raised in rich countries. It is a taxation scam of sorts. It is not going to “help the poor nations cope with the impacts of climate change” at all. That explanation is for suckers.

      The poor nations don’t want to get suckered again so they are demanding a chunk of it be set aside for their projects. Ring-fenced, allocated.

      Small projects don’t have to show additionality which was a sop to the mob about 12 years ago. Those crumbs must now meet the additionality requirement (maybe) and enter the “free market/free-for-all” of Article 6.

      I predict the collapse of COP25 and that the press will not mention a word about why (save to falsely blame Trump for departing the Accord). What bribe will Brazil accept for them to drop their “sustained opposition” to the nefarious plan embedded in Article 6? What will happen if their President turns out not to be a bribeable man?

    • Nope. A forest only captures co2 until it matures. Once fully mature, it is a net zero with as much biomass decaying and releasing co2 as is growing and absorbing it. Some things can modify that a bit. Fire can act to sequester a lot of carbon under the right conditions. If the fire produces a lot of charcoal that then gets buried by mudslides, that carbon is very stable and can remain out of the carbon cycle for thousands of years. Tree planting is a short term ephemeral solution at geological time scale

      • the most sensible CCS option then is to grow a forest to maturity, log it, use the wood for construction and repeat ad infinateum.
        …if sir feels that sequestering thin air is neceessary in the first place.

      • Large mature forests are a major source of methane. There is a cloud of methane hovering over all large tropical forests.

        It is said that the Amazon produces a large amount of oxygen but on balance, it’s net zero as it absorbs a huge amount as well. It seems that for carbon dioxide, oxygen and methane, tropical forests are net zero. Perhaps it is best turn them into a giant Permaculture garden like the forests of Central Java. At least that way they produce a lot of food.

    • It is apparent that you know very little about CCS. Almost all of the CO2 used for tertiary oil recovery comes from amine process scrubbing of impure natural gas. As you highlight in Australia.
      But you have got go do something with that CO2. In North America, it is mostly sold for tertiary oil recovery. In west Australia, no oil to recover, so is just sequestered.

      And, if you would read my essay Clean Coal in ebook Blowing Smoke, you would learn the big difference between amine process sequestration in a ‘cold’ reduced natural gas stream and sequestration in a hot exhaust gas stream. The former is ‘easy‘, the latter is ‘hard’ chemically.

  11. If you can run air liquefaction asynchronously with interruptible power, you could use solar/wind to run the air machine and the O2 to run the gas turbine for when the solar/wind doesn’t work. Then you could capture the CO2 from the gas turbine.

    The liquid N2 is not useless. Heat engines work off temperature differences. You can rig a sterling cycle engine to run off of liquid N2. Also, you can use the liquid N2 to cool the air input of the air machines.

  12. How many windmills does it take to run an electric blast furnace or an aluminum smelter?

    All of them are still not enough.

    If your goal is carbon sequestration just for the sake of it as as novelty, fine, but it can not be done at the scale required to make any measurable atmospheric impact. In fact, eliminating 100% of US human CO2 emissions would likely make exactly zero measurable impact on annual global atmospheric CO2 rise.

    This is an emotional hot button issue designed to make people FEEL better without actually doing anything more than shoveling cash into the pockets of people in the “carbon sequestration” business.

  13. The oxygen generator is not forest but algae in the oceans, the real not lungs of the planet.

  14. Rud,
    Thank you for this analysis.
    Did you have a deja vu moment, as I did?
    The important fundamental variables were known to us, and used by us, in the 1970s, to more or less eliminate for all time certain processes such as the capture, treatment and re-use of CO2. It was a non-starter even before we modelled it back then. Geoff S

  15. I think we should regard the Net Power project as ‘experimental’ rather than ‘demonstration’. We should not be so defeatist over the project’s costs – they will come down. This is very early days for the Allam cycle.
    I’m not sure why we’re comparing costs with CCGT, surely OCGT would be more appropriate? Or perhaps, better still, an offshore wind turbine.
    CCGT costs vary across the world between ~$500-1000/kWh. OCGTs are cheaper, of course.
    Allam cycle turbines aren’t the only super-critical OCGTs in the game – Sandia Labs (and others) are experimenting with other designs.

  16. Here is an excerpt from an article on Compressed Air energy storage. Theoretically it can approach 54% efficiency, but in practice, that is probably unachievable or incredibly expensive to approach. And I don’t think they included T*deltaS issues.
    Types
    Compressed air energy storage can be done adiabatically, diabatically, or isothermally:
    With adiabatic storage, the heat that appears during compression is also stored, then returned to the air when the air is expanded. This is a subject of ongoing study, but no utility scale plants of this type have been built. The theoretical efficiency of adiabatic energy storage approaches 100% for large and/or rapidly cycled devices and/or perfect thermal insulation, but in practice round trip efficiency is expected to be 70%. Heat can be stored in a solid such as concrete or stone, or more likely in a fluid such as hot oil (up to 300 °C) or a molten-salt (600 °C).
    With diabatic storage, the extra heat is removed from the air with inter coolers following compression (thus approaching isothermal compression), and is dissipated into the atmosphere as waste. Upon removal from storage, the air must be re-heated (usually in a natural gas fired burner for utility grade storage or with a heated metal mass for large Uninterruptible Power Supplies) prior to expansion in the turbine to power a generator. The heat discarded in the intercoolers degrades efficiency, but the system is simpler than the adiabatic one, and thus far is the only system which has been implemented commercially. The McIntosh CAES plant requires 0.69 kW·h (2,355 btu) of electricity and 4,100 btu (LHV) of gas for each 1.0 kW·h of electrical output [3]. A GE 7FA 2×1 combined cycle plant, one of the most efficient non-CAES natural gas plants in operation, uses 6,293 btu (LHV) of gas per kW·h generated, a 54% thermal efficiency comparable to the McIntosh 6,455 btu, a 53% thermal efficiency.
    Isothermal compression and expansion approaches (which attempt to maintain operating temperature by constant heat exchange to the environment) are only practical for rather low power levels, unless very effective heat exchangers can be incorporated. The theoretical efficiency of isothermal energy storage approaches 100% for small and/or slowly cycled devices and/or perfect heat transfer to the environment.
    In practice neither of these perfect thermodynamic cycles are obtainable, as some heat losses are unavoidable.
    More at:
    https://thematahari.wordpress.com/gas-turbines/types-of-gas-turbines/compressed-air-energy-storage/

    • Thank you for this post Dr. Bob. Much more informative then Mosher’s advertising vid.

      If I’m rembering right, one of the big Solar Thermal Plants out in California uses Morten Salt for thermal storage so they can have ’round the clock’ generation. They ended up having to run the gas fired heating system a lot more then they expected to keep the system from freezing up before morning. Another of the Plants ended up subsequently leaving out the molten salt system and only running during the day because of it.

      If something like that couldn’t even keep up with overnight storage, I doubt it would work for storage in the week to month range.

      ~¿~

    • What is the point of all of this machinery if it is no more efficient, and probably much more expensive, than conventional combined cycle gas powered turbines?

      • There IS NO point. Because CO2 DOES NOT drive the climate.

        And there’s the answer – ignore the CO2-induced-crisis bullshit!

  17. Carbon sequestration is a way to bury availabilitiy–i.e. bury a lot (30%) of the work potential of combustion. And it doesn’t matter whether you expend the availability after combustion in capturing the CO2 to bury it; or if you expend it producing O2 to burn clean and then bury it afterward. Now there may be uses for for all that CO2 if you can inject it for tertiary recovery of more fossil fuels, but this isn’t what the CO2 is bad puritans expect and opportunities are limited. And if you have a use for the coproduct N2 then that would help also; but boiling off the liquid N2 to make power is nothing more than recapturing through a thermal cycle, with all its inefficiency, some of the availability that you wasted initially producing something with no real value.

    There is one advantage to having huge stores of CO2, and that is we might tap into it in the next ice age to warm the planet back up. On the other hand if it escapes on its own then you’ll perhaps need some public service messages about climbing to safety.

    • “There is one advantage to having huge stores of CO2, and that is we might tap into it in the next ice age to warm the planet back up.”

      You’re assuming CO2 does something to the Earth’s temperature. Since there is exactly NO EMPIRICAL EVIDENCE of such hypothetical effect, your postulated “advantage” is no advantage at all.

      That “inconvenient” disadvantage you mention, however, is all too real.

  18. Carbon capture is only carbon capture if the carbon stays put… Pumping it into gas fields means some of it is coming back out, either through pumping or leaks or whatever. Unless you are reacting the CO2 into a solid material, I don’t really called it captured…maybe temporarily stored. If you turn it into a solid (at least quickly) then it really isn’t useful to force out more oil.

    So, using CO2 to recover more oil works, it’s a solid business practice, and gives CO2 a market…but I hardly think of it a a permanent storage technology. It you want to stare carbon permanently, turn it into bricks of carbon (or carbonate) and store it under the water table. Or better yet, grow more forests.

  19. These units only have a outside chance of viability if you can put them next to an oil field needing EOR and then through massive subsidies on them. Or, drive the oil price closer to $100/bbl.

    No one seems to want to seriously look into the costs of doing deepwell injection and where you can do that injection for capture?

    The costs and impracticality of CCS made the CO2 Best Available Control Technology (BACT) demonstrations in air permits I wrote slam dunk demonstrations for not doing it. I see nothing much has changed.

  20. Rud ==> Here’s a link to an article from about a decade ago that has some information on the commercial CO2 market. http://dotyenergy.com/Economics/Econ_Physical_CO2_Market.htm It’s out of date, but seems fairly sane. I think perhaps it still has some relevance. Bottom line — bulk CO2 isn’t terribly costly and thus isn’t likely to be that big a revenue source for CO2 producers. The principle cost is probably transporting it to where it is used (or with CCS, stored). There are lots of sources including natural gas wells, ammonia production, etc, etc, etc. The two major users a decade ago were petroleum production and the food and beverage production. The food and drug people want their CO2 pure. I doubt the petroleum folks care as much — within reason.

  21. Rud:

    Thanks for this.

    In light of the very few, and generally small working examples of CCS, how realistic are the EIA figures on LCOE for coal and CCCT with CCS? They don’t have to be too far off to make nuclear look cheap by comparison.

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