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Sadly at least where I live the backup generators are well-used, winter and summer alike. There was a period of about a year where we went no more than a week o

Sadly at least where I live the backup generators are well-used, winter and summer alike. There was a period of about a year where we went no more than a week or two between power outages. Absolutely a lifesaver, when you have a freezer full of frozen goods. In this context I'm saving my pennies for a solar and battery set up - it both makes financial sense when connected to the grid, and obviates the annoying side effect and high cost of running the backup generator during outages, unless they're extremely lengthy.

nine_k 2y ago
How costly is it to run a backup generator? A gallon of gasoline produces about 36 kWh, and costs about $3.6. Assuming that the motor + generator + inverter chain has efficiency is 25%, it's 9 kWh of electricity per gallon, or about 40 ¢ per kWh. Likely twice as expensive as the grid, but fine for a few days.
- jaggederest 2y ago
  Well, mine is propane, and propane is substantially less energetic than gasoline, and is also subject to delivery fees. The issue you really run into is that, even at idle, the generator burns a fixed amount of propane. The minimum is about 2 gallons per hour. Which is roughly $6 So you can imagine that, for 3 days of usage, $500 provides a strong incentive to seek out alternative sources of power. We run about $1200 a year in propane costs for the generator, estimated.
  - tzs 2y ago
    > The issue you really run into is that, even at idle, the generator burns a fixed amount of propane. The minimum is about 2 gallons per hour. Which is roughly $6 All the loads that I might consider a generator for are intermittent (well pump, fridge, microwave, space heater). I've wondered if it would make sense to get inverters for the fridge, microwave, and heater and get a pool of batteries, and just use the generator for charging batteries and powering the well pump. With a sufficient number of batteries in the battery pool it should be possible to only need to run the generator when there are sufficient batteries to charge that the generator can run at its most efficient output.
    - jaggederest 2y ago
      Yes this is roughly what I'm looking to do, but if you have an inverter and a battery charger, it seems silly not to also hook up some solar panels! At that point the generator will only run if the batteries dip below e.g. 20% charge, making it extremely affordable.

nine_k 2y ago

How costly is it to run a backup generator? A gallon of gasoline produces about 36 kWh, and costs about $3.6. Assuming that the motor + generator + inverter chain has efficiency is 25%, it's 9 kWh of electricity per gallon, or about 40 ¢ per kWh. Likely twice as expensive as the grid, but fine for a few days.

jaggederest 2y ago
Well, mine is propane, and propane is substantially less energetic than gasoline, and is also subject to delivery fees. The issue you really run into is that, even at idle, the generator burns a fixed amount of propane. The minimum is about 2 gallons per hour. Which is roughly $6 So you can imagine that, for 3 days of usage, $500 provides a strong incentive to seek out alternative sources of power. We run about $1200 a year in propane costs for the generator, estimated.
- tzs 2y ago
  > The issue you really run into is that, even at idle, the generator burns a fixed amount of propane. The minimum is about 2 gallons per hour. Which is roughly $6 All the loads that I might consider a generator for are intermittent (well pump, fridge, microwave, space heater). I've wondered if it would make sense to get inverters for the fridge, microwave, and heater and get a pool of batteries, and just use the generator for charging batteries and powering the well pump. With a sufficient number of batteries in the battery pool it should be possible to only need to run the generator when there are sufficient batteries to charge that the generator can run at its most efficient output.
  - jaggederest 2y ago
    Yes this is roughly what I'm looking to do, but if you have an inverter and a battery charger, it seems silly not to also hook up some solar panels! At that point the generator will only run if the batteries dip below e.g. 20% charge, making it extremely affordable.