My neighbor Connie got her power bill yesterday. It was $497. That was just the one for the house, she has another for the well. I got my bill today and it was $67. Mind you, $27 of that was for electricity and 40 is for taxes, fees, waste and corruption. So Connie only used $457 worth of electricity, but she gets mad when she hears about my tab. Well, I do, too. $67 will buy a really fantastic bottle of Cabernet, or two pretty good ones.
Part of the difference between her bill and mine is lifestyle and part is the fact that much of my farm is no longer connected to the co-op grid, connected instead to an oddball collection of solar projects. If somebody were to ask if you can really cut your power bill with solar, the answer would have to be “YES”, but if the question was whether or not you could save money, that’s a different deal. The less electricity you consume from a solar power system, the less it costs to build and vice versa. Saving energy saves you money, even when you have solar! Where you shop can make a big difference, too.
Connie and I have houses that are probably about the same size. Hers is older. Insulation? Don’t know. I’ve not seen in her attic or walls, but she found out there is none under the floor when a water leak required the floor be replaced. Mine has insulation in the floor and attic. Walls are R13, which is pretty minimal by today’s standard. She has a fridge and a chest freezer. I have 2 fridges and a chest freezer. She leaves lights on all the time. I don’t know what bulbs she has. I try to keep the lights off, but most are LED, in case somebody leaves them on. She has an electric water heater and mine is wood fired. Hers eats kilowatts and mine eats pine cones and junk mail during the summer. I think it is the air conditioning that is where her problem is, and she is not the only one I know with power bills above $400.
Connie is one hot babe. I mean HOT, as in Fahrenheit. She says she keeps the a/c at around 72 during the day and sets it cooler at night! My downstairs thermostat stays at 78 and the upstairs goes full on cold during the sunny hours because mine are both solar powered. To get my house to 72, I’d need a bigger inverter, maybe a pair of 8048s, to run both units at the same time and I’d need a much bigger battery to keep that going all night. The point is it would cost me more to run my house as cold as Connie’s, but from buying hardware, not from paying the power company. Of course, at some point, the hardware is paid for and the savings add up like dividend checks.
Some time when we both have time, I want to take a closer look at her insulation situation and her appliances to see where the power is really going, even though I suspect it is mainly the a/c. There’s a fix for that, if you’ve read the last half of the last solar a/c blog, the part about micro inverters. With a rig like that she could probably knock a couple of hundred bucks off the bill.
Here’s a bit of irony for you. As more regions in the world are getting their first taste of electricity, with solar, they are going crazy for a/c, which they’ve never had before. Projections for the solar build-out are being reassessed to cover the worldwide demand for air conditioning!
Ok, so let’s look at what’s going on at my house to save electricity and to replace the power company’s power with solar. First, let me say, I am not going off grid because it is nice to have the grid as my backup generator! Just flip the transfer switch and everything is back to normal $497 power bills.
Lights: Mostly LED, a few Compact Fluorescent because they haven’t died. I have one chandelier in the front hall with scads of wee incandescent candle bulbs. They’ve been there 25 years or so, I rarely use them and you could die trying to get that high to change them out. They are a problem I will leave to the next generation. Some lights get left on all the time. Some I’ve given up trying to turn them off, so all of the lighting in the house is on the solar circuits. Incidental to this, the internet satellite dish and the wifi are on this circuit, a legacy of when I had to keep my business running even when the power company was down. Old power bills are not available for research at this time, but I think I recall that when my old 24v solar power system came on it took about 200 kilowatt-hours (KWH) off the bill, or about $25 a month.
The old 24v system, including the Not-Really-8KW Melt-o-Matic inverter. The antique analog meter kind of gives balance to this digital stuff.
Of course, there was no electric water heater, but the grid powers a small fan in the outdoor wood furnace. That’s a fair trade-off there. This phase of the system was very limited, but also provided power for loads the house never saw. A Yamaha golf car replaced an F250 as my on-farm truck. At that time, the Yamaha was a just a load and not a battery resource, like it is in the present system. There were also lights and power tools run by the system and no attempt was ever made to meter this.
Firing up the amps with solar can save on the power bill, too.
Here is what the power consumption was looking like over a period of time. This is from my July 2019 power bill. The last “J” is the July bill, but for the June electricity. Look back 13 months to July 2018. That’s actually June, when it is pretty mild. August (July) ran on up to 837kwh. That’s without paying for the lights, of course. Note the plateau for November-February. That’s running the house without heating or cooling, aside from the air handler fan. Then in March we see another step down and then it just doesn’t go back up. There was another change.
What happened was the bigger 48v solar power system got switched over. It had been running for months, but there were some wiring changes and other things to consider, including minimizing downtime during the changeover. I knew the new system was stable, having run it alongside the 24v system. When I changed over, I put the extra power to work, cutting over the two fridges, freezer, home entertainment, some outlets, dishwasher, microwave and both coffee makers. We are serious about our coffee. That got us down to the 200kwh neighborhood, at least until cooling season begins.
The new 48v system under construction, before lightning blew up the 12kw inverter.
Getting through spring with most loads off the grid was easy. The challenge for summer was to get the a/c running on solar. The homemade inverter just couldn’t handle the surges. Read the a/c blogs to see what happened there. Short version is, it worked.
The new inverter under construction, using case and transformer of the old inverter. Note the MidNite Solar lightning catcher down near the bottom left. I love the cool blue glow and the thing actually works!
The homebrew inverter comes to life on the barely running 48v system. There are still 378 small solar panels to move over! Yeesh! Those stupid magnetic “light switches” are actually quite handy to stick to your system, just in case…
So here is the result of running the big cooling load, the lights and basic appliances on solar. The August bills from last year to this year dropped 600kwh, even while keeping the house cooler and powering 2 utility vehicles. So the next question is when do I upgrade my inverter to 10kw (I have the parts) and pile up some more battery capacity? The inverter upgrade is just a matter of finding time. Come January, the Solar Shed will be getting its last expansion, stretching from 80’ to over 100’, depending largely on how many working solar shingles I can come up with. Maybe an additional 3500 watts! The cost of building materials has gotten crazy, so we’ll get that part out of the way before we talk new batteries. The current set is in good shape, so no sense in spending 5 grand on a new monster battery, just yet.
The September 2019 power consumption of 210kwh is pretty remarkable when you consider how many days we had over 100 degrees F.
If you’ve not read some of my other posts, you may be wondering why I am not just running grid-tie. That’s not an option with our power co-op, so the only time we even talk about it is to gripe that we don’t have it. So, hybrid systems are the way we go. Proof is in the power bill that it is working.
Now as for Connie’s problem, I’m going to sit down with her and see if there is something we can do with solar to help her bill. Yeah, I could tell her to turn up the thermostat 5 degrees, but I don’t have a good track record getting women to do as I tell them, so I won’t bother. If we can cut $200 a month during the summer months with a microinverter conversion to her compressor, that could pay for itself in a reasonable time, especially with the cheap prices on the pv modules from Sun Electronics. I’m sure she has a heat pump (which I hate), but she might not see great savings in the winter if she really ices down the place, then. I’ll let you know if we come up with a successful plan.
–Neal
