3 ms·

With a battery, you could run your generator at peak efficiency when it's running, and idle it otherwise, significantly reducing your running costs.

toast0 2y ago
Yeah, but even at peak efficiency, I don't think $/kWh on propane is going to be better than $/kWh from my utility. A battery system would be nice though, all things considered, so I could run the generator for fewer hours during an outage: only running the generator when my demand is high or the battery needs to charge would reduce the time spent at low load where efficiency is poor.
- robocat 2y ago
  > so I could run the generator for fewer hours during an outage: only running the generator when my demand is high or the battery needs to charge would reduce the time spent at low load where efficiency is poor. There is little point worrying about marginal efficiency when power is out because saving a few dollars over a few hours is not worth optimising for. - High fixed costs (batteries & inverter) would dominate small operating costs (propane, wear&tear).
  - toast0 2y ago
    Marginal efficiency could allow for longer system runtime with the stored fuel, though. That would be important if fuel deliveries were unavailable, and since utility outages (for me) correlate with poor weather that causes poor road conditions, it seems like a reasonable thing to consider. Also, I think maybe a battery supplied inverter would give me less wobbly power than I get at low load --- I'm pretty sensitive to flickery lighting. Probably not worth it though at the moment. I suspect it would be simpler and lower cost to double my fuel storage capacity. Lived experience says in 6 years, the maximum duration outage was less than 3 days, and my storage capacity is plenty good for that.
    - robocat 2y ago
      From your past comments I think you are near Seattle, and that area looks fairly red on the USGS national seismic hazard map! > the maximum duration outage was less than 3 days Past performance is no guarantee of future results! My semi-rural parents were at one end of the faultline of the Canterbury earthquake and my sister lives on a rural property on top of the Kaikoura earthquake. If you are in an earthquake zone, my lived experience has been that planning for more than a weeks disruption is very worthwhile. They both have wood burners and had months of firewood so heating was fine. They used gas cookers for a while. Both have septic tanks and both had non-powered water supplies (no electric powered wells - they had tanks fed from roof and hillside). I think my sister lost a couple of chest freezers of meat because power was out. Many people had no serviced power for an extended period of time. My sister lost their ADSL internet (their property has zero cellphone coverage). She'd be okay now with her Starlink. After an earthquake, you cannot buy a generator (they are all sold quickly). Getting gas deliveries might be difficult (bridges and roads were fucked near my sisters). I will instal solar with batteries and I live in a city. Power, sewage and water were out in many parts of Christchurch for a long time after the Christchurch earthquake. I'm no prepper. I am just happy to hedge my insurance bets if the price is right! Then again: after three major earthquakes I would hope we all learn a little... If you're visiting NZ then come visit.

toast0 2y ago

Yeah, but even at peak efficiency, I don't think $/kWh on propane is going to be better than $/kWh from my utility. A battery system would be nice though, all things considered, so I could run the generator for fewer hours during an outage: only running the generator when my demand is high or the battery needs to charge would reduce the time spent at low load where efficiency is poor.

robocat 2y ago
> so I could run the generator for fewer hours during an outage: only running the generator when my demand is high or the battery needs to charge would reduce the time spent at low load where efficiency is poor. There is little point worrying about marginal efficiency when power is out because saving a few dollars over a few hours is not worth optimising for. - High fixed costs (batteries & inverter) would dominate small operating costs (propane, wear&tear).
- toast0 2y ago
  Marginal efficiency could allow for longer system runtime with the stored fuel, though. That would be important if fuel deliveries were unavailable, and since utility outages (for me) correlate with poor weather that causes poor road conditions, it seems like a reasonable thing to consider. Also, I think maybe a battery supplied inverter would give me less wobbly power than I get at low load --- I'm pretty sensitive to flickery lighting. Probably not worth it though at the moment. I suspect it would be simpler and lower cost to double my fuel storage capacity. Lived experience says in 6 years, the maximum duration outage was less than 3 days, and my storage capacity is plenty good for that.
  - robocat 2y ago
    From your past comments I think you are near Seattle, and that area looks fairly red on the USGS national seismic hazard map! > the maximum duration outage was less than 3 days Past performance is no guarantee of future results! My semi-rural parents were at one end of the faultline of the Canterbury earthquake and my sister lives on a rural property on top of the Kaikoura earthquake. If you are in an earthquake zone, my lived experience has been that planning for more than a weeks disruption is very worthwhile. They both have wood burners and had months of firewood so heating was fine. They used gas cookers for a while. Both have septic tanks and both had non-powered water supplies (no electric powered wells - they had tanks fed from roof and hillside). I think my sister lost a couple of chest freezers of meat because power was out. Many people had no serviced power for an extended period of time. My sister lost their ADSL internet (their property has zero cellphone coverage). She'd be okay now with her Starlink. After an earthquake, you cannot buy a generator (they are all sold quickly). Getting gas deliveries might be difficult (bridges and roads were fucked near my sisters). I will instal solar with batteries and I live in a city. Power, sewage and water were out in many parts of Christchurch for a long time after the Christchurch earthquake. I'm no prepper. I am just happy to hedge my insurance bets if the price is right! Then again: after three major earthquakes I would hope we all learn a little... If you're visiting NZ then come visit.