4 ms·

I came here to say pretty much the same thing. When I was working at All Power Labs we did exactly this, ran a 150kW Cummins turbo diesel generator off of wood

I came here to say pretty much the same thing. When I was working at All Power Labs we did exactly this, ran a 150kW Cummins turbo diesel generator off of wood gas. I had the woodgas control unit tell the generator to inject the minimum amount of diesel to idle, then adjusted the power output by adjusting a butterfly valve throttle of stoichiometric mixture of woodgas and air (well, likely lean so that there was added oxygen for the diesel). I wish more folks were interested in woody biomass gasification. There is a tremendous amount of biomass in the world that could be utilized for power production that will already be burned or composted (releasing CO2 and methane into the atmosphere).

the_third_wave 4y ago
Having worked at APL you might have an idea whether that project/company is still ongoing, their website seems to have stalled somewhere around 2019? I've toyed with building a GEK or some sort of derivative but this has not gotten pas the drawing stage yet. My interest lies mainly in combined heat-power generation from wood chips as that is a fuel often used by farmers around here, it would be beneficial is they got electrical power 'for free' in the process. From what I've seen at APL their products and prices are mostly tailored to NGOs and research institutes, I'm aiming for something which can be afforded by the average farmer. Especially with the looming 'energy crisis' there should be a market for such, it also combines well with a solar PV installation in that the latter can provide power and hot water in late spring and summer while the former provides more heat and electricity in winter.
- nanomonkey 4y ago
  They are still going, but mostly in research on biochar generation. Creating electricity was deemed a race to the bottom as solarpanels have become so ubiquitous. They recently had an open house where they suggested that this would be their new focus. When I worked there, I tried to shoot for something closer to what you are interested in. I assumed that farmers and forest management groups would want a small gasification unit that could be trailered to a location and used to run chippers, pelletizers and produce heat and hot water for workers, etc. The 10 and 20 kW power pallets do all this...but were never really as reliable as they need to be for the price point ($35k). Getting them grid tied was a huge expense even though easily doable. I've been contemplating a smaller ~2kW version that would put out a households amount of electricity and hot water for domestic usage, but I really don't like internal combustion engines, and believe that this is the ideal use case for a Sterling engine generator. Sadly those are impossible to find, and as WhisperGen went out of business I don't believe there are businesses interested in making them available.
  - the_third_wave 4y ago
    Well, I'm in Sweden which seems to be somewhat of a Stirling engine knowledge centre with Kockums (a shipyard) using them for "undetectable" submarines and Swedish Stirling [1] (a company based around Kockums' Stirling technology) using them for CHP installations running off flare gas and other waste gases for heat and power. That's all fine but their products are aimed at small-scale utilities and industry, not individual farm or single-household domestic applications. There are plenty of toy Stirling engines around and clearly also plenty of large-scale ones but I have not found one in the 15-30 kW range I'm aiming for. It would be possible to build one but it would be much easier to get one off the shelf somewhere. Another option I've been toying with is a small gas turbine [2] which should increase reliability and lower maintenance over a piston ICE - which I assume is the reason you don't like ICEs in these applications?. Has APL considered that route? [1] https://swedishstirling.com/ https://swedishstirling.com/ [2] https://www.sciencedirect.com/topics/engineering/micro-gas-turbine https://www.sciencedirect.com/topics/engineering/micro-gas-t...
    - nanomonkey 4y ago
      Yes, we had a small turbine, they aren't cheap or as easily serviceable as piston ICE generators. The biggest problem with turbines and any internal combustion engine is that your fuel needs to be clean. With woodgas, you often have particulates, or volatile gases that will precipitate out as temperature and pressures fluctuate within the engine. This fine soot and tar gas can cause fouling over time. For this reason, I think externally combusted engines (Stirlings or steam) are the way to go for a small scale simple cogeneration plant.
      - the_third_wave 4y ago
        That would make it possible to use/modify any of the existing gasifying wood boilers - something like these by Atmos [1] - for this purpose by e.g. replacing the bottom ceramic inset for one which includes either the hot side of a Stirling engine or a heat exchanger for such. Steam under enough pressure to drive a turbine... while it might sound promising it would involve a whole new host of regulations which would increase the price as well as yearly conformity checks, at least where I have lived - the Netherlands and Sweden. This might not be viable for these small-scale applications. [1] https://www.atmos.eu/english/kotle-001-kotle-na-drevo https://www.atmos.eu/english/kotle-001-kotle-na-drevo

the_third_wave 4y ago

Having worked at APL you might have an idea whether that project/company is still ongoing, their website seems to have stalled somewhere around 2019? I've toyed with building a GEK or some sort of derivative but this has not gotten pas the drawing stage yet. My interest lies mainly in combined heat-power generation from wood chips as that is a fuel often used by farmers around here, it would be beneficial is they got electrical power 'for free' in the process. From what I've seen at APL their products and prices are mostly tailored to NGOs and research institutes, I'm aiming for something which can be afforded by the average farmer. Especially with the looming 'energy crisis' there should be a market for such, it also combines well with a solar PV installation in that the latter can provide power and hot water in late spring and summer while the former provides more heat and electricity in winter.

nanomonkey 4y ago
They are still going, but mostly in research on biochar generation. Creating electricity was deemed a race to the bottom as solarpanels have become so ubiquitous. They recently had an open house where they suggested that this would be their new focus. When I worked there, I tried to shoot for something closer to what you are interested in. I assumed that farmers and forest management groups would want a small gasification unit that could be trailered to a location and used to run chippers, pelletizers and produce heat and hot water for workers, etc. The 10 and 20 kW power pallets do all this...but were never really as reliable as they need to be for the price point ($35k). Getting them grid tied was a huge expense even though easily doable. I've been contemplating a smaller ~2kW version that would put out a households amount of electricity and hot water for domestic usage, but I really don't like internal combustion engines, and believe that this is the ideal use case for a Sterling engine generator. Sadly those are impossible to find, and as WhisperGen went out of business I don't believe there are businesses interested in making them available.
- the_third_wave 4y ago
  Well, I'm in Sweden which seems to be somewhat of a Stirling engine knowledge centre with Kockums (a shipyard) using them for "undetectable" submarines and Swedish Stirling [1] (a company based around Kockums' Stirling technology) using them for CHP installations running off flare gas and other waste gases for heat and power. That's all fine but their products are aimed at small-scale utilities and industry, not individual farm or single-household domestic applications. There are plenty of toy Stirling engines around and clearly also plenty of large-scale ones but I have not found one in the 15-30 kW range I'm aiming for. It would be possible to build one but it would be much easier to get one off the shelf somewhere. Another option I've been toying with is a small gas turbine [2] which should increase reliability and lower maintenance over a piston ICE - which I assume is the reason you don't like ICEs in these applications?. Has APL considered that route? [1] https://swedishstirling.com/ https://swedishstirling.com/ [2] https://www.sciencedirect.com/topics/engineering/micro-gas-turbine https://www.sciencedirect.com/topics/engineering/micro-gas-t...
  - nanomonkey 4y ago
    Yes, we had a small turbine, they aren't cheap or as easily serviceable as piston ICE generators. The biggest problem with turbines and any internal combustion engine is that your fuel needs to be clean. With woodgas, you often have particulates, or volatile gases that will precipitate out as temperature and pressures fluctuate within the engine. This fine soot and tar gas can cause fouling over time. For this reason, I think externally combusted engines (Stirlings or steam) are the way to go for a small scale simple cogeneration plant.
    - the_third_wave 4y ago
      That would make it possible to use/modify any of the existing gasifying wood boilers - something like these by Atmos [1] - for this purpose by e.g. replacing the bottom ceramic inset for one which includes either the hot side of a Stirling engine or a heat exchanger for such. Steam under enough pressure to drive a turbine... while it might sound promising it would involve a whole new host of regulations which would increase the price as well as yearly conformity checks, at least where I have lived - the Netherlands and Sweden. This might not be viable for these small-scale applications. [1] https://www.atmos.eu/english/kotle-001-kotle-na-drevo https://www.atmos.eu/english/kotle-001-kotle-na-drevo