An environmental “poop de grace” – Manure could heat your home

From the UNIVERSITY OF WATERLOO and the “what’s that smell coming from the furnace?” department.

Farm manure could be a viable source of renewable energy to help reduce greenhouse gas emissions that cause global warming.

Researchers at the University of Waterloo are developing technology to produce renewable natural gas from manure so it can be added to the existing energy supply system for heating homes and powering industries. That would eliminate particularly harmful gases released by naturally decomposing manure when it is spread on farm fields as fertilizer and partially replace fossil natural gas, a significant contributor to global warming.

“There are multiple ways we can benefit from this single approach,” said David Simakov, a professor of chemical engineering at Waterloo. “The potential is huge.”

Simakov said the technology could be viable with several kinds of manure, particularly cow and pig manure, as well as at landfill sites.

In addition to being used by industries and in homes, renewable natural gas could replace diesel fuel for trucks in the transportation sector, a major source of greenhouse gas emissions.

To test the concept, researchers built a computer model of an actual 2,000-head dairy farm in Ontario that collects manure and converts it into biogas in anaerobic digesters. Some of that biogas is already used to produce electricity by burning it in generators, reducing the environmental impact of manure while also yielding about 30 to 40 percent of its energy potential.

Researchers want to take those benefits a significant step further by upgrading, or converting, biogas from manure into renewable natural gas. That would involve mixing it with hydrogen, then running it through a catalytic converter. A chemical reaction in the converter would produce methane from carbon dioxide in the biogas.

Known as methanation, the process would require electricity to produce hydrogen, but that power could be generated on-site by renewable wind or solar systems, or taken from the electrical grid at times of low demand. The net result would be renewable natural gas that yields almost all of manure’s energy potential and also efficiently stores electricity, but has only a fraction of the greenhouse gas impact of manure used as fertilizer.

“This is how we can make the transition from fossil-based energy to renewable energy using existing infrastructure, which is a tremendous advantage,” said Simakov, who collaborates with fellow chemical engineering professor Michael Fowler.

The modelling study showed that a $5-million investment in a methanation system at the Ontario farm would, with government price subsidies for renewable natural gas, have about a five-year payback period.

A paper on modelling of a renewable natural gas generation facility at the Ontario farm, which also involved a post-doctoral researcher and several Waterloo students, was recently published in the International Journal of Energy Research.



77 thoughts on “An environmental “poop de grace” – Manure could heat your home

  1. “with government subsidies…have about a five year payback period.” Another Show Me The Money! scheme. The highest landforms in southern Florida are garbage dumps, now covered over with containment dirt and sporting pipes that collect methane from inside the old heaps. Why no just put the cow poop into conventional garbage heaps?

    • While that has some benefits on a local, distributed scale (at a dairy farm, e.g.), the transportation cost of moving the manure around negates any benefit on a mass scale.

      On the local scale the manure digesters are as popular with neighbors as pig and chicken farms and for the same malodorous reason.

  2. I had professors enthusiastic about this idea in the 1970s. Is it really still in the conceptual model stage?

  3. “Known as methanation, the process would require electricity to produce hydrogen, but that power could be generated on-site by renewable wind or solar systems, or taken from the electrical grid at times of low demand.”

    Oh, good. You can heat your home and your food, unless, of course, the sun isn’t shining and the wind isn’t blowing (say in a deep, high pressure chill) in which case you can freeze, or wait until “times of low demand” which would be… never because all the wind farms and solar arrays for the rest of the grid are experiencing the same lack of production.

    • It doesn’t smell as bad when it is cold outside. Look on the bright side.

      [The mods can verify that frozen porta-potties in upstate NY hightshift at -15 deg do not smell either. .mod]

    • Geez, methanation, I have heard of this for years. In separating the oxygen from the carbon, you need to put in more energy than than you will get out of it. If you want to use it for storage, just store the H2 without the losses and costs of the methanation step.

    • Exactly! Isn’t this what heats most homes and fuels the cooking fires in India? Isn’t this a big part of the Asian Brown Cloud wafting across the planet? And now … we sophisticated, modernized, western civilizations must regress to Stone Age ? This reminds me of the UN scolding our beef eating, and demanding that westerners need to start eating crickets, bugs, and grubs … again … like our stone aged counterparts. My simple answer? No.

      • The manure from our handful of cattle is recycled by dung beetles…that’s a proper and efficient system as far as I can tell.

  4. ‘From the UNIVERSITY OF WATERLOO and the “what’s that smell coming from the furnace?” department.’

    It is commonly known as BS….

  5. Problem is the manure doesn’t get wasted as it is. It gets used to fertilize fields. The scientists have no clue how the real world works. Almost nothing of value is going to waste as it is – so if we take the fertilizer and turn it into heating fuel – there will be a shortage somewhere else. Someone will have to then purchase NG based fertilizers for a net gain of zero (or less!)

    • Rotting manure produces heat, as anyone who has had the job of forking manure into a spreader on a cold spring morning knows. A big pile gets downright hot.

      I’d look for a grant utilizing this concept as a “new” idea, but apparently it is a very old idea in colder climates.

      When the Vikings in Greenland were facing desperately cold winters as the MWP shifted to the LIA they had their livestock move indoors with them. I don’t imagine they fussed much about the smell of manure. Spring cleaning also fertilized the fields. At their peak they had over 2000 cows and over 100,000 goats and sheep. (What I always wonder about is how they kept their herds watered when all water turned to ice.)

      People were amazingly inventive and frugal in the past, because if they didn’t they died. Now all that inventive ability goes into writing grant requests.

      I’m going to devise slowly moving conveyor belts moving rotting manure under houses, to heat floors, with some gizmo to gather the gases. And the best thing of all is that I gather grants are exempt from taxes, so I’ll be free from heat generated by the pile of —- the IRS buries me under at this time every year.

      • How hot? Hot enough to use for a hydronic heating system? How big of a pile? So instead of a furnace heating water in a set of coils, I could just put a coil in a manure heap and get hot water? Sounds like free heat to me. Intriguing

        /half way sarcastic/

      • “I’m going to devise slowly moving conveyor belts moving rotting manure under houses, to heat floors, with some gizmo to gather the gases.”

        “Want flies with that?” (My quote from WUWT on a Japanese hamburger-from-cow-patties pilot study a few years back.)

      • I remember that comment. It was one where coffee gets onto the computer screen afterwards. It also is one reason I like this site so much. Good humor.

    • Yeah, loved the idiotic quote:
      “That would eliminate particularly harmful gases released by naturally decomposing manure when it is spread on farm fields as fertilizer and partially replace fossil natural gas, a significant contributor to global warming.”

      So by burning the biomass (and releasing its CO2) we avoid allowing the biomass to biologically decompose (via bacteria) and release its CO2. Seems like all we are doing is starving bacteria and not replenishing necessary nutrients into the soil. …and merely using more energy to process the manure into burnable material, energy that was freely provided by the bacteria.

      Who do they think they are fooling? I doubt even themselves.

      • – Well if it knocks-down the HORRENDOUS fug you get driving-by downwind of big farm fields freshly-spread with liquid manure, I for one am all for it!

  6. “… would eliminate particularly harmful gases released by naturally decomposing manure when it is spread on farm fields as fertilizer …”

    Which hamful gasses from natural decomposition?
    Which natural substance do they propose to use as fertilizer?

  7. Wait, wait, isn’t manure the number one fuel source in India? So instead of scattering the manure or the resulting composted material on farm fields, which apparently is bad for the environment, we convert it to natural gas using electricity to produce hydrogen. Manure to biogas has been around a long time. Why would any of this be an improvement?

    • Manuring your field can hardly be considered harmful for the environment. By the way how has this planet survived all these millions of years with zillions of animals defecating all over the place?

      • I think the problem being addressed is that in colder climates (e.g. Canada) there’s not much point in letting the cattle into snow covered fields in Winter. So they stay in the barn. The resulting manure is stockpiled and is spread on the fields in Spring after the ground thaws (from the top down) and the resulting morass of mud firms up enough for machinery to not sink out of sight. So manure sits in storage decomposing and generating gas for much of the year. The idea seems to be to do something useful with the gases.

        Somebody around here probably actually works or has worked on a Northern dairy farm and should feel free to correct me if I’m wrong.

        I have to say, that the “solution” seems awfully complex. Wouldn’t it be easier to design generators and/or heaters that can just burn whatever noxious mixture of gases the manure emits as fuel?

      • “Wouldn’t it be easier to design generators and/or heaters that can just burn whatever noxious mixture of gases the manure emits as fuel?”

        They are called diesel engines.

      • I have a friend who puts composted buffalo chips on her garden. Much better than commercial kind.

  8. No just no.

    Hunter gatherers and people who live where no other heating resources exist use this. There is a reason it is the last heating choice of primitive cultures.

  9. As part of a waste disposal system for a pig farm or a dairy, perhaps. Making sure the manure is “well rotted” before it is spread anywhere near crops grown for food is required, and a methane digester would surely do that. As an energy production system, it is the usual silly green kludge.

  10. So in Waterloo they are doing something practical (again). Well done guys and gals! Nothing like practical engineering.

    • A little late for Watlooers, I worked on “shit” like this as a student at U of Calgary 40 plus years ago. Bottom line, it might be economic if you don’t have to truck the manure. Still the answer 40 years later.

      • I should add, nor compress the methane to normal distribution pipeline pressure, nor remove the CO2 from it to provide saleable fuel gas quality.

  11. Apparently the people defecating in the streets of San Francisco are providing a public service.

  12. “Manure could heat your home”.
    Yes, and if I had eggs, I could have ham and eggs. If I only had ham. And if I actually ate ham.

  13. In the UK it’s called anaerobic digestion. There is so little energy in cr@p, that food crops have to added to make the system viable, even with massive subsidies.

  14. A politician in every home talking non stop would accomplish the same goal……… But who would want that……

  15. Local biogas production for large livestock operations is a no-brainer for those with the assets to invest — in some cases it helps to comply with manure disposal regulations. The biogas can be used, as mentioned, for electrical generation, directly fueling generators designed to burn propane and for heating of livestock barns etc.
    Adding in expensive processing steps and exporting the gas off-farm is just added complexity for little added value. Most livestock operations can consume all the available gas on-site.

  16. What’s new and novel here, enhancing the production of methane? It doesn’t really say. They are talking about things that are fairly common practices: land application of manures and generation and use of methane from anaerobic digestion of animal manures. So, are they going to use electricity to produce more of something to produce electricity. I’d like to see that energy balance. Oh, free electricity from solar or turbines. Right.

    • The part that is new is to add hydrogen to the process to produce additional methane from the CO2 in the off-gasses. They are making more methane by using electricity to create it. It would be an economic advantage only if natural gas is more valuable than electricity.

      • Which might be the case if you are getting wholesale electric rates from someone like the TVA, otherwise forget about it.

      • Nothing new here other than in situ generation of hydrogen which screws the energy balance. Anaerobic digestion to produce CH4 and CO2 starts with hydrolysis of wastes, acidogenic bacteria converting the waste to sugar and amino acids and then methanogenisis to make CH4 and CO2. Happens in marsh gas, buried wastes, landfills and manure piles. I had a carbon rich anaerobic digestor that produced 70% methane. I have a friend who has made a career of consulting in conversion of manure and other wastes to methane for heat and electricity. I was the environmental manager of a company that generated electricity from this process in 16 landfills and one pipeline quality facility. We had 500 diesel electric generators using landfill gas methane for electricity.

        What’s new about this other than a more expensive way to do what’s been going on for millions of years?

  17. Built a model…what nonsense. Anerobic digesters have been commercial for decades. Most US large hog farms and feed lots use them to produce winter and process (cooked feed mash for easier digestion) heating fuel while disposing of the point concentrated manure. Isnt economic to haul off for many miles and field spread. On my 350 head dairy farm we have a large concrete manure composting pit and two large manure spreaders towed by the largest tractor (~150 HP): grate bed/thrower for fresh mostly winter, spead in spring before tlling, tank sprayer for composted liquid mostly for summer/fall after alfalfa cuttings.

  18. Known as methanation, the process would require electricity to produce hydrogen, but that power could be generated on-site by renewable wind or solar systems, or taken from the electrical grid at times of low demand.

    In other words: “and magic happens”

  19. I’d like to see the bucket chemistry that shows how the reported process differs from anaerobic digesters that produce “biogas”. Cows are poor food converters and the excreta contains a lot of carbon-chain energy. The AD process converts it into something usable – it would otherwise be aerobically digested and just wiffle away into the atmosphere as CO2. The energy yield from cow slurry is relatively poor. If the digester is fed with silage the yield of gas is much higher, yet better with waste edible oils, with maize (corn) or oilseeds better still. At this point the cows are no longer needed and the herd is sold. As the whole shebang is dependent on Feed-In Tariffs and Renewables Obligation Certificates, when these are reduced or withdrawn the banks foreclose on the capital borrowings. As there is no longer any milk to sell the farmer goes bust, the banks get the farm, the milk-buyers get the milk from France. This is how it works. SNAFU.

  20. Errr…doesn’t this fly in the face of getting rid of all those nasty, polluting, farm animals? I can see the vegans refusing to be kept warm by an animal product…yet another special-interest group offended in our quest to ‘save’ the planet.

  21. Have the universities sunk this low? Chinese peasants have been using manure to produce cooking gas for only God knows how long.

  22. Being something of a literalist, I have difficulty with the the term “renewable natural gas”. To me “renewable’ implies that once one has used, in this instance, the gas it can then be restored to its original state – made new again – and re-used. Perhaps the University of Waterloo needs to invest in a good dictionary.

    • And “renewable natural gas” made by using chemicals! Chemicals… what are they thinking. Scientists… /s

  23. Charles Darwin was writing a book when he died.
    He regarded it as vastly more important than anything he or anyone had previously published.

    Today’s homework and wonderation for everyone:
    What could be even more important than ‘evolution’?

    Clue: It was going to be all about earthworms

  24. Anaerobic digestion has been the sensible thing to do with sewage for decades. The downside is that the resulting gas has a low calorific value because it contains CO2

    Where this proposal gets interesting is that plan to add hydrogen and use another established process, methanation, to turn the CO2 into more methane. The problem is the cost of the hydrogen, which they propose to get by electrolysing water using intermittent electricity. Not only is electrolysis an expensive way to get hydrogen but if the plant is only going to operate part of the time it needs to be large and it needs to have a lot of hydrogen storage so that the methanation can continue where the electrolysis is shut down.

    Like a lot of other ideas today it requires massive taxpayer subsidies to be viable.

  25. They should leave manure out in the field where it is consumed by earth worms which indirectly enriches the soil.

    People who have no clue about soil enrichment should be kept miles away from policy makers.

    • The solids and liquids left after anaerobic digestion are an excellent fertiliser and they do not have the odour and health problems that spreading raw sewage on fields does.

      • The residual fertilizer is N-heavy though as the C has gone into the methane. Nobody likes to mention that.

      • feliksch, fertilizer doesn’t need *any* carbon, and untreated manure simply decomposes in place. Putting that carbon to good use simply makes the nitrogen more accessible to the plants. Of course, the dosage on the fields must be controlled at a useful level, but that’s true for any fertilization. “Nobody likes to mention that” because it is irrelevant.

    • The trouble is that with intensive farming the runoff can be too polluting, preprocessing and extracting energy at the same time can be beneficial.

  26. Dried dung is used for fuel by a billion people.

    ‘Researchers at the University of Waterloo are developing technology to produce renewable natural gas from manure’

    Seems like they are trying to complicate the mundane.

    One wonders what ‘renewable natural gas’ is. Producing natural gas from manure is not enough, apparently.

  27. Manure if valuable stuff. George Patton when fighting in France in WW I and WWII noted that one could judge the relative wealth of the farmers by the size of their manure piles. Why use it for heat if you have other sources?

  28. “to help reduce greenhouse gas emissions that cause global warming.”

    This is how the propaganda machine works. Every article presents this “fact”, so that the average person simply doesn’t question it.

  29. Does use of the “renewable natural gas” produce less CO2 per unit of energy than the use of natural natural gas?

  30. Robert Crosby, an engineer in Alaska has made two-stage methane digesters that separate the process into two steps, the first producing CO2, the second CH4 of much better quality than single-stage digesters. By venting the CO2 through an ozone scrubber, all odors can be destroyed. The direct-from-digester gas is about 2/3 of pipeline quality and no hydrogen or sabatier reactor are needed.

    His bottom-up, build-it-only-if-it-makes-sense philosophy appeals to me-

  31. For the people objecting to manure digestion because it is a good fertilizer, removing the CO2 and methane actually makes the other nutrients in the manure more available, and by getting that decomposition done in a controlled fashion, can reduce the unpleasant smells otherwise emitted by manure spreading (provided the CO2 offgas is treated with ozone).

    It’s NOT a zero-sum game; putting manure (both human and animal) through a digestion process before use as crop fertilizer extracts useful fuel, kills pathogens, reduces odors, and make nutrients more available. I’m dismayed by the lack of understanding shown by some commenters above.

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