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This is traditionally called "micro CHP". It has potential in places without district heating infrastructure, otherwise DH CHP is much more efficient. These ar

by zurn 12y ago

This is traditionally called "micro CHP". It has potential in places without district heating infrastructure, otherwise DH CHP is much more efficient. These aren't really new. Eg here is an article looking at an existing commercial gas powered Stirling micro CHP that's quiet and designed for your house: http://www.f09.fh-koeln.de/imperia/md/content/personen/sommer_klaus/forschung/rehva_micro_chp.pdf http://www.f09.fh-koeln.de/imperia/md/content/personen/somme... - there's also a comparison to an ICE based equivalent and it has much better electricity generation efficiency. The total efficiency is going to depend a lot on where you use it. The heating output is locked to the electrical output so you're always going to generate the 5 kW of heat per each kW of electricity, so you have to stop the plant when your hot water tank and house is heated up - or start throwing away all the heat and just run it as a low efficiency genset. The large pool case sounds like a fit, but from another perspective it's just greenwashing the huge energy sink of the pool. The laundries & restaurants case sounds better here. Or regular houses in climates where a lot of heating is needed most of the year.

dredmorbius 12y ago
If you run the number on based on an assumed 30% efficiency and retail gas costs of $0.8 - $1.50 a therm (I think that's reasonable), then you come up with a cost per kWh of electricity within the $0.09 - $0.12 range many US utilities charge. That is, on a cost-of-electricity basis it's a wash. Mind: gas delivery networks likely would crumble (hopefully not literally) under the increased demand. Depending on system costs, this could be viable as a back-up power generation option (blackouts, etc.), where electrical service might fail but the gas supply would still work. Capturing and making use of waste heat could indeed be useful. I see the possibility of full grid independence as very slim, and not particularly compelling (with distributed small, renewable, and intermittent generation, the grid is a useful way to move surpluses and deficits around). Though being somewhat immune to major grid disruptions is a possibility. I'd also keep an eye on natural gas trends. Supplies aren't endless, though the US EIA's estimates suggest a reference resource case of increasing extraction through 2040 at least, the less optimistic low resource case suggesting a peak by 2030. With fracked oil extraction very likely to peak before 2020, a transfer of fuel and energy uses onto natural gas will change market dynamics considerably. I've got my doubts as to how long gas will remain cheap. And suspect that its increased use in transport (EIA sees a large role in trucking) other uses may be limited.
fab13n 12y ago
Admittedly, the biggest news is that they might produce a cogeneration heater for <$10K. A nice thing with cogeneration is that it works best when photovoltaic panels work the least. My case isn't typical, I live on a boat in Europe. She has panels which could push 5-6kWh/day on average in summer (they don't because our batteries are full long before that), but only 1kWh/day in december. We need 2-3kWh/day to be comfortable. So, we need more than what PV panels provides exactly when we also need to heat the boat, so a cost-effective CHP solution would be great. Also, I'd like this to run on wood pellets, or diesel fuel: replacing the electrical grid with the natural gaz one is a bad idea, especielly considering that the expected yield of non-conventional extraction methods is continuously and rapidly adjusted down.

by zurn 12y ago

dredmorbius 12y ago

If you run the number on based on an assumed 30% efficiency and retail gas costs of $0.8 - $1.50 a therm (I think that's reasonable), then you come up with a cost per kWh of electricity within the $0.09 - $0.12 range many US utilities charge. That is, on a cost-of-electricity basis it's a wash. Mind: gas delivery networks likely would crumble (hopefully not literally) under the increased demand. Depending on system costs, this could be viable as a back-up power generation option (blackouts, etc.), where electrical service might fail but the gas supply would still work. Capturing and making use of waste heat could indeed be useful. I see the possibility of full grid independence as very slim, and not particularly compelling (with distributed small, renewable, and intermittent generation, the grid is a useful way to move surpluses and deficits around). Though being somewhat immune to major grid disruptions is a possibility. I'd also keep an eye on natural gas trends. Supplies aren't endless, though the US EIA's estimates suggest a reference resource case of increasing extraction through 2040 at least, the less optimistic low resource case suggesting a peak by 2030. With fracked oil extraction very likely to peak before 2020, a transfer of fuel and energy uses onto natural gas will change market dynamics considerably. I've got my doubts as to how long gas will remain cheap. And suspect that its increased use in transport (EIA sees a large role in trucking) other uses may be limited.

fab13n 12y ago

Admittedly, the biggest news is that they might produce a cogeneration heater for <$10K. A nice thing with cogeneration is that it works best when photovoltaic panels work the least. My case isn't typical, I live on a boat in Europe. She has panels which could push 5-6kWh/day on average in summer (they don't because our batteries are full long before that), but only 1kWh/day in december. We need 2-3kWh/day to be comfortable. So, we need more than what PV panels provides exactly when we also need to heat the boat, so a cost-effective CHP solution would be great. Also, I'd like this to run on wood pellets, or diesel fuel: replacing the electrical grid with the natural gaz one is a bad idea, especielly considering that the expected yield of non-conventional extraction methods is continuously and rapidly adjusted down.