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I have solar. So far, it feels like more of a "feel good" thing than a major economic benefit. Getting a 10kw solar array installed cost ~25k in our territory.

I have solar. So far, it feels like more of a "feel good" thing than a major economic benefit. Getting a 10kw solar array installed cost ~25k in our territory. Dealing with the local electric company was a huge pain, and the array doesn't actually feed the house (we sell power back to the grid). To really maximize the benefit, you need a powerwall, so you can store surplus energy, continue service during outages, and avoid taking a hit if the net metering agreement changes in the future. We're actually exploring this by way of the Ford F-150 lightning acting as a battery backup, but that also requires upgrading the house to a 400 amp service, so you really start feeling like you're getting in to sunk cost territory.

jerf 5y ago
This was one of my major disappointments when I looked into solar the first time. I don't want to stick panels on top of my house that are basically just feeding back into the grid. I want to have panels that first feed my house, and maybe if there's extra feed it into the grid, but if the grid goes down I still have a more-or-less functional house. A big part of solar's value to me is the renewable, off-grid backup power. Solar has the interesting and useful characteristic that it keeps working even if things have really gone to pot and you've even lost gas and water for some reason. Having lots of houses like this scattered all over the place greatly increases civilizational resilience. (That is, I'm not so much trying to plan for "The End Of The World" just for me personally with my own solar install, but want the resilience at the societal level, and might be willing to pay to help it along.) If solar's just going to feed back into the grid, I might as well just let the utility companies manage it themselves. It's more efficient than anything I can do myself. Unfortunately, it seems like the way solar works helps that goal much less than I'd like. I hardly need multiple kilowatts of power backing a single functional outlet that almost seems begrudgingly provided. I'd be interested in anyone who has experience in perhaps managing to set their house up the way I describe, what magic words to Google or say to installers to talk about this, and how much more money it may have been.
- OneEyedRobot 5y ago
  The real money ends up being in the power storage. Obviously there's such a thing as 'night' and multiple days without full sun (or snow on your roof depending on the area). I wonder how many electric F-150s will get sold to people on the basis of using them as a whole-house battery. I fully agree on your point of the lack of logic to grid-based solar. No doubt large scale facilities can be placed in better areas, be cheaper per watt, have higher uptime, are able to afford the more exotic power storage (dams for one). Now, if it were me, I'd start with new construction designed around low power usage. LED lighting, efficient computers, chest freezer turned into a refrigerator, no electric heat or dryers or transfer fans for gas heaters. The sticking point would tend to be A/C but I think that can be mitigated via small house size, insulation, and use of efficient split systems. The smaller the electricity use the more tractable the problem.
- bengold14 5y ago
  I used to manage solar installations, couple of things: 1. Electrically, solar does feed your house first. It interconnects before the meter and into your main electric panel. The reason it doesn't work during an outage is because of regulations requiring solar to turn off during power outages so that electricians fixing downed lines don't have surprise power from random houses after they turn off the grid power. 2. If you want solar to work during an electric outage you need to install a battery backup that can feed it AC power and disconnect it from the grid during a grid failure. However, you need a pretty big battery to power a full house for a long time so it's generally cheaper and easier to have a gas generator backup if you are worried about this. Batteries are really just good for energy arbitrage purposes these days. 3. There are inverters that have an outlet that works during grid outages, even without batteries (https://www.sma-sunny.com/us/how-to-explain-secure-power-supply-to-homeowners/ https://www.sma-sunny.com/us/how-to-explain-secure-power-sup...). They generally cost the same
- mapmap 5y ago
  The term you are looking for is called islanding. When the grid goes down you want it to throw an automatic transfer switch and power your house from solar and/or batteries. When the grid returns, you want it to resync the AC wave and draw from the grid as needed. Check out the Victron Multiplus as an example.
  - jerf 5y ago
    Thank you. Sometimes working out that correct search term is the hardest part of the process!
- 1958325146 5y ago
  My house is set up like you describe. The whole solar/battery system never interconnects with the grid, and is instead set up like a generator. There is a transfer switch to choose between "generator" power and grid power. If there is some exceptional weather and the battery gets too low, we switch to grid. If the battery is full and the day is sunny we often dump power into the car, air conditioning, or whatever.
xur17 5y ago
That's one thing I've always wondered about solar. If it truly just flows back into the grid, and you don't get access to it during a power outage, surely a centralized solar energy installation would be a lot more efficient than installing them on everyone's roofs. You end up paying much higher installation and maintenance costs - the only real advantage is that it's a plot of land that's readily available.
- OneEyedRobot 5y ago
  It wouldn't surprise me (although I'm not any kind of power engineer) if a world of house-based grid-tied solar wouldn't be a bit of a management nightmare for the power company as opposed to large plants. I expect we get away with it right now due to rarity.
  - toomuchtodo 5y ago
    South Australia has so much solar, at times there is zero grid demand. It is a management nightmare for grid operators, but that's what they're getting paid for (instead of generation, which is shifting to direct payment from consumers with solar on their roofs). The future of grids is orchestration between variable demand and variable generation, along with pumped storage, battery storage, and long distance transmission.
    - OneEyedRobot 5y ago
      If everyone is producing electricity, who pays the bills?
      - Abekkus 5y ago
        Same people who pay for the roads and traffic signals?
OneEyedRobot 5y ago
What required the 400 amp service? I do like the F150 as a backup power source, but there's probably a catch. I see that a Tesla Powerwall holds 13.5 kWh, and the truck is 115-155 kWh. Average US house is 30 kWh / day? It sounds doable but not cheap.
- boulos 5y ago
  I'm not sure about the 400 A comment either, but there's at least two "catches" to the F-150: it's ~$90k for that configuration and it's unclear how the charge/discharge duty cycle will affect it. To be clear, even at $90k that's cheaper than buying a pile of power walls or similar. So it seems like it's a power wall array plus a free truck :).
  - dylan604 5y ago
    Except if the truck is out of town on a fishing trip but the rest of the family is at home, the powerwall is unavailable to the family where the power is out.
  - tmountain 5y ago
    The 90k price tag is for the highest trim model. The entry level is ~40k. We know the entry level won't be able to serve as a battery backup; however, there ostensibly a bunch of trim levels between entry and "ultra" with their own respective price points, and my understanding is that the details are still unclear regarding the lowest tier that supports this feature. If you have details, I'd love to see them.
    - OneEyedRobot 5y ago
      >We know the entry level won't be able to serve as a battery backup Why is that? A missing feature?
      - tmountain 5y ago
        Originally I read that the inverter is part of the truck and would not be included in the lowest "pro" trim model. After further research, it sounds like the bidirectional charging comes as part of the extended range battery upgrade, which you can apply to any trim model (starts at $10,000 and goes down in price at higher trim levels). https://www.f150gen14.com/forum/threads/trim-pricing-for-2022-f-150-lightning-revealed-in-survey-email-before-and-after-tax-credit.4242/ https://www.f150gen14.com/forum/threads/trim-pricing-for-202...

jerf 5y ago

This was one of my major disappointments when I looked into solar the first time. I don't want to stick panels on top of my house that are basically just feeding back into the grid. I want to have panels that first feed my house, and maybe if there's extra feed it into the grid, but if the grid goes down I still have a more-or-less functional house. A big part of solar's value to me is the renewable, off-grid backup power. Solar has the interesting and useful characteristic that it keeps working even if things have really gone to pot and you've even lost gas and water for some reason. Having lots of houses like this scattered all over the place greatly increases civilizational resilience. (That is, I'm not so much trying to plan for "The End Of The World" just for me personally with my own solar install, but want the resilience at the societal level, and might be willing to pay to help it along.) If solar's just going to feed back into the grid, I might as well just let the utility companies manage it themselves. It's more efficient than anything I can do myself. Unfortunately, it seems like the way solar works helps that goal much less than I'd like. I hardly need multiple kilowatts of power backing a single functional outlet that almost seems begrudgingly provided. I'd be interested in anyone who has experience in perhaps managing to set their house up the way I describe, what magic words to Google or say to installers to talk about this, and how much more money it may have been.

OneEyedRobot 5y ago
The real money ends up being in the power storage. Obviously there's such a thing as 'night' and multiple days without full sun (or snow on your roof depending on the area). I wonder how many electric F-150s will get sold to people on the basis of using them as a whole-house battery. I fully agree on your point of the lack of logic to grid-based solar. No doubt large scale facilities can be placed in better areas, be cheaper per watt, have higher uptime, are able to afford the more exotic power storage (dams for one). Now, if it were me, I'd start with new construction designed around low power usage. LED lighting, efficient computers, chest freezer turned into a refrigerator, no electric heat or dryers or transfer fans for gas heaters. The sticking point would tend to be A/C but I think that can be mitigated via small house size, insulation, and use of efficient split systems. The smaller the electricity use the more tractable the problem.
bengold14 5y ago
I used to manage solar installations, couple of things: 1. Electrically, solar does feed your house first. It interconnects before the meter and into your main electric panel. The reason it doesn't work during an outage is because of regulations requiring solar to turn off during power outages so that electricians fixing downed lines don't have surprise power from random houses after they turn off the grid power. 2. If you want solar to work during an electric outage you need to install a battery backup that can feed it AC power and disconnect it from the grid during a grid failure. However, you need a pretty big battery to power a full house for a long time so it's generally cheaper and easier to have a gas generator backup if you are worried about this. Batteries are really just good for energy arbitrage purposes these days. 3. There are inverters that have an outlet that works during grid outages, even without batteries (https://www.sma-sunny.com/us/how-to-explain-secure-power-supply-to-homeowners/ https://www.sma-sunny.com/us/how-to-explain-secure-power-sup...). They generally cost the same
mapmap 5y ago
The term you are looking for is called islanding. When the grid goes down you want it to throw an automatic transfer switch and power your house from solar and/or batteries. When the grid returns, you want it to resync the AC wave and draw from the grid as needed. Check out the Victron Multiplus as an example.
- jerf 5y ago
  Thank you. Sometimes working out that correct search term is the hardest part of the process!
1958325146 5y ago
My house is set up like you describe. The whole solar/battery system never interconnects with the grid, and is instead set up like a generator. There is a transfer switch to choose between "generator" power and grid power. If there is some exceptional weather and the battery gets too low, we switch to grid. If the battery is full and the day is sunny we often dump power into the car, air conditioning, or whatever.

xur17 5y ago

That's one thing I've always wondered about solar. If it truly just flows back into the grid, and you don't get access to it during a power outage, surely a centralized solar energy installation would be a lot more efficient than installing them on everyone's roofs. You end up paying much higher installation and maintenance costs - the only real advantage is that it's a plot of land that's readily available.

OneEyedRobot 5y ago
It wouldn't surprise me (although I'm not any kind of power engineer) if a world of house-based grid-tied solar wouldn't be a bit of a management nightmare for the power company as opposed to large plants. I expect we get away with it right now due to rarity.
- toomuchtodo 5y ago
  South Australia has so much solar, at times there is zero grid demand. It is a management nightmare for grid operators, but that's what they're getting paid for (instead of generation, which is shifting to direct payment from consumers with solar on their roofs). The future of grids is orchestration between variable demand and variable generation, along with pumped storage, battery storage, and long distance transmission.
  - OneEyedRobot 5y ago
    If everyone is producing electricity, who pays the bills?
    - Abekkus 5y ago
      Same people who pay for the roads and traffic signals?

OneEyedRobot 5y ago

What required the 400 amp service? I do like the F150 as a backup power source, but there's probably a catch. I see that a Tesla Powerwall holds 13.5 kWh, and the truck is 115-155 kWh. Average US house is 30 kWh / day? It sounds doable but not cheap.

boulos 5y ago
I'm not sure about the 400 A comment either, but there's at least two "catches" to the F-150: it's ~$90k for that configuration and it's unclear how the charge/discharge duty cycle will affect it. To be clear, even at $90k that's cheaper than buying a pile of power walls or similar. So it seems like it's a power wall array plus a free truck :).
- dylan604 5y ago
  Except if the truck is out of town on a fishing trip but the rest of the family is at home, the powerwall is unavailable to the family where the power is out.
- tmountain 5y ago
  The 90k price tag is for the highest trim model. The entry level is ~40k. We know the entry level won't be able to serve as a battery backup; however, there ostensibly a bunch of trim levels between entry and "ultra" with their own respective price points, and my understanding is that the details are still unclear regarding the lowest tier that supports this feature. If you have details, I'd love to see them.
  - OneEyedRobot 5y ago
    >We know the entry level won't be able to serve as a battery backup Why is that? A missing feature?
    - tmountain 5y ago
      Originally I read that the inverter is part of the truck and would not be included in the lowest "pro" trim model. After further research, it sounds like the bidirectional charging comes as part of the extended range battery upgrade, which you can apply to any trim model (starts at $10,000 and goes down in price at higher trim levels). https://www.f150gen14.com/forum/threads/trim-pricing-for-2022-f-150-lightning-revealed-in-survey-email-before-and-after-tax-credit.4242/ https://www.f150gen14.com/forum/threads/trim-pricing-for-202...