5 ms·

I have quite a bit of surplus power most of the year (on the order of 10-15kWh/day). If I use it, great, if not... it just doesn't get pulled out of the panels.

I have quite a bit of surplus power most of the year (on the order of 10-15kWh/day). If I use it, great, if not... it just doesn't get pulled out of the panels. The office is standalone (and way more trouble than it's worth to grid tie) I know you said grid-tie isn't worth the trouble, but until the USA moves to more renewable energy for power production, that might yield the best carbon reduction, depending on how much you could otherwise sequester per KWh. The national average CO2 emissions for power production is 947.2 lbs CO2 per megawatt-hour [1] (or 0.947 lbs/KWh). So unless you can sequester 10-15lbs or more of CO2 a day, then you may be better off sending your excess power to the grid if your goal is carbon reduction. Though I'm not sure how to account for the actual CO2 reduction - is the national average fair? Should you use the average per state since states vary widely in their renewable energy status? Is there some other way to determine how much CO2 you've offset? [1] https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references https://www.epa.gov/energy/greenhouse-gases-equivalencies-ca...

Syonyk 5y ago
I guarantee my office is radically more trouble than it's worth to grid tie. I'd have to put a second meter in, or lose net metering on my house, I'd have to trench across an awful lot of quite hostile ground (literal rock outcroppings between "where my office is" and "where the grid tie would be"), upgrade my house's electrical panel, and pretty much entirely redo my office power system from the ground up, get a permit for my office (it's under the size minimum, but with hard wired power it would need a permit), rebuild my panel mounts, and an awful lot of other stuff. It would easily run me $10k to do all this, before I was able to cross tie a single kWh. And, in the bargain, I'd lose the standalone power system that is my office, because getting battery backed stuff approved out here is basically impossible. I tried for the house system, and after 18 months of fighting red tape that exists to fund the red tape, I gave up and built a grid tie system without a backup. I get that it sounds easy, but it would cost more to interconnect it than the standalone system cost in the first place, drop me out of a very sweet 25 year net metering grandfathering, and leave me with a far less capable property in the deal. Sorry, just not interested in that.
- smoyer 5y ago
  Put an electric car charger on the side of your shed?
  - Syonyk 5y ago
    When I redo the wiring in my shed, that's one of the things I plan on doing - more exterior outlets. Right now, I don't have an easy way to plug the Volt in down there, but on days when it's used early and has the full day to recover, I probably could. The main limit is that I only have a 2kW single phase (120V) inverter down there, so I can't really charge at a full 2kW, and I can't charge hard while also running my air conditioner. I can spare 500-800W, no problem, but beyond that, it starts to be harder. I've got a bigger inverter on a trailer I can parallel in, though, and that might work - run 900W out of my office into the aux charger on that, with another 900W coming in from solar, and then charge the car at 3.3kW, buffering off the battery pack. I need to play with it a bit more this winter, but having some good outdoor outlets on my office will make things easier.
- throwaway09223 5y ago
  Sounds like attacking the bureaucracy around solar power regulation is a great place to start. I get it. I have a solar system too and there's no way in hell I'm updating it.
- thinkcontext 5y ago
  Given how much you are curtailing it could be the case that your system is worse off with respect to carbon than if you just used grid electricity. We'd have to do the math but there are large embodied emissions in your pv panels and battery, your curtailing means you are making up for those more slowly.
  - Syonyk 5y ago
    Oh, I'm almost certain it is. But, given that, the more energy I can make and utilize with it, the lower the effective carbon per kWh is. It's also, of value to me, a totally standalone power system, and a good R&D system for me to experiment with, because I can do things without bothering the house system. If I screw up and black out my office, well... I've blacked out my office. However, my system is also rather a good bit more reliable than the grid power on the house, which is nice for remote work.

Syonyk 5y ago

I guarantee my office is radically more trouble than it's worth to grid tie. I'd have to put a second meter in, or lose net metering on my house, I'd have to trench across an awful lot of quite hostile ground (literal rock outcroppings between "where my office is" and "where the grid tie would be"), upgrade my house's electrical panel, and pretty much entirely redo my office power system from the ground up, get a permit for my office (it's under the size minimum, but with hard wired power it would need a permit), rebuild my panel mounts, and an awful lot of other stuff. It would easily run me $10k to do all this, before I was able to cross tie a single kWh. And, in the bargain, I'd lose the standalone power system that is my office, because getting battery backed stuff approved out here is basically impossible. I tried for the house system, and after 18 months of fighting red tape that exists to fund the red tape, I gave up and built a grid tie system without a backup. I get that it sounds easy, but it would cost more to interconnect it than the standalone system cost in the first place, drop me out of a very sweet 25 year net metering grandfathering, and leave me with a far less capable property in the deal. Sorry, just not interested in that.

smoyer 5y ago
Put an electric car charger on the side of your shed?
- Syonyk 5y ago
  When I redo the wiring in my shed, that's one of the things I plan on doing - more exterior outlets. Right now, I don't have an easy way to plug the Volt in down there, but on days when it's used early and has the full day to recover, I probably could. The main limit is that I only have a 2kW single phase (120V) inverter down there, so I can't really charge at a full 2kW, and I can't charge hard while also running my air conditioner. I can spare 500-800W, no problem, but beyond that, it starts to be harder. I've got a bigger inverter on a trailer I can parallel in, though, and that might work - run 900W out of my office into the aux charger on that, with another 900W coming in from solar, and then charge the car at 3.3kW, buffering off the battery pack. I need to play with it a bit more this winter, but having some good outdoor outlets on my office will make things easier.
throwaway09223 5y ago
Sounds like attacking the bureaucracy around solar power regulation is a great place to start. I get it. I have a solar system too and there's no way in hell I'm updating it.
thinkcontext 5y ago
Given how much you are curtailing it could be the case that your system is worse off with respect to carbon than if you just used grid electricity. We'd have to do the math but there are large embodied emissions in your pv panels and battery, your curtailing means you are making up for those more slowly.
- Syonyk 5y ago
  Oh, I'm almost certain it is. But, given that, the more energy I can make and utilize with it, the lower the effective carbon per kWh is. It's also, of value to me, a totally standalone power system, and a good R&D system for me to experiment with, because I can do things without bothering the house system. If I screw up and black out my office, well... I've blacked out my office. However, my system is also rather a good bit more reliable than the grid power on the house, which is nice for remote work.