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Not sure about the laws in the US, but my wife works as a chemical engineer at a sewage treatment plant here in Sweden and they run _all_ incoming sewage throug

Not sure about the laws in the US, but my wife works as a chemical engineer at a sewage treatment plant here in Sweden and they run _all_ incoming sewage through a aneorobic digester. This generates enough methane to run all the busses in Stockholm and then some. Our car also (VW Passat) also runs on bio-methane. Important to note that this is 100% carbon-neutral since it uses carbon already in cycle, as opposed to fossil natural gas which adds carbon to the cycle.

nothrabannosir 10y ago
Is it true methane is so much worse a geeenhouse gas than co2 ("20x")? Wouldn't that mean him turning methane into co2 is not just carbon neutral, but great for the environment?
- masklinn 10y ago
  > Is it true methane is so much worse a geeenhouse gas than co2 ("20x")? Wouldn't that mean him turning methane into co2 is not just carbon neutral, but great for the environment? It's true and it actually has a GWP[0] of ~80 over 20 years (so over 20 years a given mass of methane traps 80 times as much heat as the same mass of CO2), although it degrades back to CO2 and water in 12 years. So yes if you're releasing the carbon into the atmosphere either way, it is much, much better to release it as CO2 than as methane. [0] https://en.wikipedia.org/wiki/Global_warming_potential https://en.wikipedia.org/wiki/Global_warming_potential
  - mbag 10y ago
    From what I understood, they were using methane in internal combustion engines, so they are not releasing methane into atmosphere, rather burning it and producing CO2. I would assume that some of the methane is going to end up in atmosphere (engine efficiency, leaking from gas tank), but compare that to untreated pig manure, which would produce said methane anyhow.
    - mirimir 10y ago
      Well, we're probably talking about industrial-scale pig farming here. So yes, the carbon in that manure would otherwise likely end up as atmospheric methane. If you applied it sparingly to the soil, much of the carbon would get incorporated into humus. But large pig farms don't have enough land, so they spread thick, and you get methane. Another issue is that most of the carbon in that manure comes from feed corn. And most of the energy in feed corn comes from ammonia fertilizer, which is made from fossil methane. But hey, it's still a win compared to field spreading. Right.
- SideburnsOfDoom 10y ago
  > Wouldn't that mean him turning methane into co2 is not just carbon neutral, but great for the environment? Yes, though if you use the aneorobic digester to make the methane in the first place, it's moot.
  - fastbeef 10y ago
    But that methane is used to drive a combustion engine. Otherwise the ammonium and methane from the manure would just emit into the atmosphere. It's basically free energy.
  - deleted 10y ago
    [deleted]
  - masklinn 10y ago
    That's only if the original pile of manure would not release the methane on its own.
- flukus 10y ago
  In theory. There is probably a lot of greenhouse emissions that goes into feeding the pigs though, like with most vegetable farming.
  - masklinn 10y ago
    The discussion is only about the "outflow". The assumption is that you're releasing a set amount of carbon, but you can release it either as methane or as CO2 (and extract some energy out of it in the process).
    - deleted 10y ago
      [deleted]

nothrabannosir 10y ago

Is it true methane is so much worse a geeenhouse gas than co2 ("20x")? Wouldn't that mean him turning methane into co2 is not just carbon neutral, but great for the environment?

masklinn 10y ago
> Is it true methane is so much worse a geeenhouse gas than co2 ("20x")? Wouldn't that mean him turning methane into co2 is not just carbon neutral, but great for the environment? It's true and it actually has a GWP[0] of ~80 over 20 years (so over 20 years a given mass of methane traps 80 times as much heat as the same mass of CO2), although it degrades back to CO2 and water in 12 years. So yes if you're releasing the carbon into the atmosphere either way, it is much, much better to release it as CO2 than as methane. [0] https://en.wikipedia.org/wiki/Global_warming_potential https://en.wikipedia.org/wiki/Global_warming_potential
- mbag 10y ago
  From what I understood, they were using methane in internal combustion engines, so they are not releasing methane into atmosphere, rather burning it and producing CO2. I would assume that some of the methane is going to end up in atmosphere (engine efficiency, leaking from gas tank), but compare that to untreated pig manure, which would produce said methane anyhow.
  - mirimir 10y ago
    Well, we're probably talking about industrial-scale pig farming here. So yes, the carbon in that manure would otherwise likely end up as atmospheric methane. If you applied it sparingly to the soil, much of the carbon would get incorporated into humus. But large pig farms don't have enough land, so they spread thick, and you get methane. Another issue is that most of the carbon in that manure comes from feed corn. And most of the energy in feed corn comes from ammonia fertilizer, which is made from fossil methane. But hey, it's still a win compared to field spreading. Right.
SideburnsOfDoom 10y ago
> Wouldn't that mean him turning methane into co2 is not just carbon neutral, but great for the environment? Yes, though if you use the aneorobic digester to make the methane in the first place, it's moot.
- fastbeef 10y ago
  But that methane is used to drive a combustion engine. Otherwise the ammonium and methane from the manure would just emit into the atmosphere. It's basically free energy.
- deleted 10y ago
  [deleted]
- masklinn 10y ago
  That's only if the original pile of manure would not release the methane on its own.
flukus 10y ago
In theory. There is probably a lot of greenhouse emissions that goes into feeding the pigs though, like with most vegetable farming.
- masklinn 10y ago
  The discussion is only about the "outflow". The assumption is that you're releasing a set amount of carbon, but you can release it either as methane or as CO2 (and extract some energy out of it in the process).
  - deleted 10y ago
    [deleted]