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This article is ludicrously short on technical details -- anyone have more?

by samps 17y ago

Devilboy 17y ago
The system uses natural gas to generate electricity locally. They say it's up to 85% efficient if you also use the heat it generates to heat your home. Modern large scale natural gas-powered plants seems to be about 60% efficient according to my quick Google searches. If this thing is cheap enough it could be worthwhile, but only in cold climates where you can use the generated heat.
- seriousken 17y ago
  Does that 60% figure include transmission losses, or is it just thermal efficiency? I'm guessing the latter.
  - Devilboy 17y ago
    Transmission losses are probably not included, but for reference this new device is only 35% efficient if you cannot use the heat it generates. If your house (or the weather) is already warm enough, you're not going to come out ahead.
  - hammmatt 17y ago
    The industry standard for measuring the efficiency of a power generator does not include transmission losses. However, I have seen people include it in the past as a way of manipulating the numbers. I doubt this is the case with this number. It should be close to 60%
    - seriousken 17y ago
      If it doesn't include transmission losses, then how can you meaningfully compare the net efficiency of a colocated device vs. a remote power station?
- cookingrobot 17y ago
  A more efficient natural gas generator is fine, but not exactly "green" compared to wind, solar, thermal, hydro, nuclear or other carbon neutral tech. Does this device include carbon capture, or does it just spew CO2?
  - joezydeco 17y ago
    The Bloom energy cell supposedly works without combustion. So no CO/CO2 etc. But there have to be some byproducts somewhere.
    - nradov 17y ago
      Combustion has nothing to do with it. If it's a natural gas fuel cell then it's reacting mainly CH4 and O2 to produce mostly H2O and CO2, plus electricity and heat. http://www.naturalgas.org/environment/technology.asp#fuelcells http://www.naturalgas.org/environment/technology.asp#fuelcel...
  - mbrubeck 17y ago
    Yeah, apparently it can (and does) run on methane captured from landfills. That plus efficiency provides the "green" angle.
- easp 17y ago
  Most of the reason that natural gas generators are not more efficient is that utilities aren't willing to pay for that efficiency. Natural gas is more expensive than coal but it can be used in realively inexpensive gas-turbine generators that can be spun up and down quickly to meet rapid swings in demand. Since those plants are only opearted part-time, utilities worry more about capital efficiency than fuel efficiency. Unless these things are cheaper, their added efficiency might not win many existing natural gas generation customers.
shib71 17y ago
Is it just me or is the writing style oddly insubstantial? I can't put my finger on it.
- BigZaphod 17y ago
  IMO, it reads almost like a fictional news interview for a TV show. :/
- gojomo 17y ago
  Seems like a transcript of the TV segment -- so compared to something that was written to be read, it's more informal, less substantial, more dependent on timing/delivery (which is lost in the transcript) for its effect on the listener.
dandelany 17y ago
The Sabatier reaction creates methane and water from CO2 and hydrogen: CO2 + 4H2 → CH4 + 2H2O NASA is investigating its use for harvesting water from exhaled CO2 on the ISS, and it has been proposed as a way to make fuel on mars. [http://en.wikipedia.org/wiki/Sabatier_reaction http://en.wikipedia.org/wiki/Sabatier_reaction] Based on the way it's presented in the video, I'm guessing he may have found a way to catalyze this reaction in reverse using methane and water as fuel, and probably also reharvesting the leftover H2 in the process. (Granted, I have no clue if any of this is possible). This process must inevitably produce CO2, but the question is, does it produce significantly less of it than the current "generate power in one place and ship it around the country" system? If so, it must be heralded for what it is - an incremental improvement in energy efficiency; and companies will treat it as such, as it will be cheaper. But it's not an be-all, end-all solution to our problems.
- dandelany 17y ago
  Check out this 2008 patent application with Sridhar's name on it: http://www.faqs.org/patents/app/20080318092 http://www.faqs.org/patents/app/20080318092 Abstract: A high temperature electrochemical system, such as a solid oxide fuel cell system, generates hydrogen and optionally electricity in a fuel cell mode. At least a part of the generated hydrogen is separated and stored or provided to a hydrogen using device. A solid oxide regenerative fuel cell system stores carbon dioxide in a fuel cell mode. The system generates a methane fuel in an electrolysis mode from the stored carbon dioxide and water by using a Sabatier subsystem. Alternatively, the system generates a hydrogen fuel in an electrolysis mode from water alone.
  - _debug_ 17y ago
    Thanks for the detective work!

This article is ludicrously short on technical details -- anyone have more?

by samps 17y ago

This article is ludicrously short on technical details -- anyone have more?

The system uses natural gas to generate electricity locally. They say it's up to 85% efficient if you also use the heat it generates to heat your home. Modern large scale natural gas-powered plants seems to be about 60% efficient according to my quick Google searches. If this thing is cheap enough it could be worthwhile, but only in cold climates where you can use the generated heat.

seriousken 17y ago
Does that 60% figure include transmission losses, or is it just thermal efficiency? I'm guessing the latter.
- Devilboy 17y ago
  Transmission losses are probably not included, but for reference this new device is only 35% efficient if you cannot use the heat it generates. If your house (or the weather) is already warm enough, you're not going to come out ahead.
- hammmatt 17y ago
  The industry standard for measuring the efficiency of a power generator does not include transmission losses. However, I have seen people include it in the past as a way of manipulating the numbers. I doubt this is the case with this number. It should be close to 60%
  - seriousken 17y ago
    If it doesn't include transmission losses, then how can you meaningfully compare the net efficiency of a colocated device vs. a remote power station?
cookingrobot 17y ago
A more efficient natural gas generator is fine, but not exactly "green" compared to wind, solar, thermal, hydro, nuclear or other carbon neutral tech. Does this device include carbon capture, or does it just spew CO2?
- joezydeco 17y ago
  The Bloom energy cell supposedly works without combustion. So no CO/CO2 etc. But there have to be some byproducts somewhere.
  - nradov 17y ago
    Combustion has nothing to do with it. If it's a natural gas fuel cell then it's reacting mainly CH4 and O2 to produce mostly H2O and CO2, plus electricity and heat. http://www.naturalgas.org/environment/technology.asp#fuelcells http://www.naturalgas.org/environment/technology.asp#fuelcel...
- mbrubeck 17y ago
  Yeah, apparently it can (and does) run on methane captured from landfills. That plus efficiency provides the "green" angle.
easp 17y ago
Most of the reason that natural gas generators are not more efficient is that utilities aren't willing to pay for that efficiency. Natural gas is more expensive than coal but it can be used in realively inexpensive gas-turbine generators that can be spun up and down quickly to meet rapid swings in demand. Since those plants are only opearted part-time, utilities worry more about capital efficiency than fuel efficiency. Unless these things are cheaper, their added efficiency might not win many existing natural gas generation customers.

shib71 17y ago

Is it just me or is the writing style oddly insubstantial? I can't put my finger on it.

BigZaphod 17y ago
IMO, it reads almost like a fictional news interview for a TV show. :/
gojomo 17y ago
Seems like a transcript of the TV segment -- so compared to something that was written to be read, it's more informal, less substantial, more dependent on timing/delivery (which is lost in the transcript) for its effect on the listener.

dandelany 17y ago

The Sabatier reaction creates methane and water from CO2 and hydrogen: CO2 + 4H2 → CH4 + 2H2O NASA is investigating its use for harvesting water from exhaled CO2 on the ISS, and it has been proposed as a way to make fuel on mars. [http://en.wikipedia.org/wiki/Sabatier_reaction http://en.wikipedia.org/wiki/Sabatier_reaction] Based on the way it's presented in the video, I'm guessing he may have found a way to catalyze this reaction in reverse using methane and water as fuel, and probably also reharvesting the leftover H2 in the process. (Granted, I have no clue if any of this is possible). This process must inevitably produce CO2, but the question is, does it produce significantly less of it than the current "generate power in one place and ship it around the country" system? If so, it must be heralded for what it is - an incremental improvement in energy efficiency; and companies will treat it as such, as it will be cheaper. But it's not an be-all, end-all solution to our problems.

dandelany 17y ago
Check out this 2008 patent application with Sridhar's name on it: http://www.faqs.org/patents/app/20080318092 http://www.faqs.org/patents/app/20080318092 Abstract: A high temperature electrochemical system, such as a solid oxide fuel cell system, generates hydrogen and optionally electricity in a fuel cell mode. At least a part of the generated hydrogen is separated and stored or provided to a hydrogen using device. A solid oxide regenerative fuel cell system stores carbon dioxide in a fuel cell mode. The system generates a methane fuel in an electrolysis mode from the stored carbon dioxide and water by using a Sabatier subsystem. Alternatively, the system generates a hydrogen fuel in an electrolysis mode from water alone.
- _debug_ 17y ago
  Thanks for the detective work!