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Beer & Queso
21

I’m not an Austin Energy customer (outside the city limits) so no city subsidy for me. I did get an ERCOT rebate and a federal tax credit spread over two tax years. I’m not sure if either of those are still being offered.

I used to keep a spreadsheet of kWh generated vs. kWh used. Unfortunately my inverter was installed with 3G cellular connectivity which was shut down in 2022, so I don’t have any detailed data since then. Supposedly it can be switched to ethernet, but I haven’t taken the time or effort to run a cable to it, and it’s too small a job for any installers to give me the time of day.

Net metering has had some ups and downs. Green Mountain used to be the only REP offering unlimited net metering (sell back as much as you generate, even if it’s more than you use) with symmetrical inflow/outflow pricing. They stopped offering this in 2021-2022, leaving me unable to build up a balance for extra power generated; I could only offset what I used, and still paid a minimum $9.95/month for the Oncor delivery charge. This especially hurt in the winter months when I generated less and used more (my home is all electric) and cost me hundreds of dollars extra each year. Once that happened I started contacting installers asking about battery systems, but again, apparently even that is too small a job: no one wanted to sell me batteries without also selling me panels.

Fortunately my contract with Green Mountain was up last month and I saw TXU is now offering symmetrical unlimited net metering, so I switched and jumped on a new 3-year term. While it’s too early to tell, I expect I’ll go back to paying roughly nothing over a 12-month span like I did before: build up a balance during spring/summer/fall and use it up during the winter.

I did have to replace my roof in summer 2023 from golf ball sized hail that spring. The solar uninstall/reinstall cost about $12k (per my State Farm estimate) which almost doubled the claim total. The roofing company coordinated everything with the solar company so that the panels came off 1-2 days before and were reinstalled about a week after the roof was done.

As for the panels themselves, as of 2022 (most recent data I have) their performance hadn’t degraded much if at all. Year-over-year peak days under similar conditions were well within about 0.5%, which beats the 1%/year degradation I was told to expect. I suspect they will last a very long time, and if anything the inverter will need replacing before the panels themselves.

So, seven years later, would I do solar panels again? 4-5 years ago I would’ve said “yes, but not financed”. Since the last three years my answer lands somewhere between “maybe, in a different state, and only with batteries” and “hell no”. I currently have a new roof, solar panels that we paid off early and which are still performing well, and a shiny new unlimited net metering plan, so there’s that, for now. However, I’m not thrilled about the volatility of the Texas retail electricity market’s product offerings, and losing net metering for 2-3 years very tangibly hurt and felt like a major rug pull. I wish I had batteries, but today I’d be seven years into the ten-year warranty that most battery systems had at the time, and I’d probably be biting my nails about that right now.

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22

Can you plug in a WiFi pod nearby and run Ethernet from that to the inverter?

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On the wider point of solar, I can see how Texas’ Wild West approach to energy can play havoc with a long term strategy. I’m also pretty sure that solar salesmen are folks who were too over the top for used car dealers.

After thinking on this a little, a battery bank is likely my path of least resistance. Fighting the HOA to change the rules to comply with TX law and then getting them to approve the actual installation sounds exhausting and expensive.

My electric bill is never more than $200 (it is highest in winter because heating with electricity is terribly inefficient) so my ability to claw back the system cost is limited. Also limited is my roof space; it might be a different proposition if I could add some extra panels to sell the overage.

Still, a “generator” lock out requires a permit and an electrician, and they run anywhere from $700-$1,000, on top of the battery pack. Having no car, though, means that being able to stay at home during an extended outage is a tangible benefit. My battery needs would be relatively modest too.

I don’t know if I’m doing this right, but I average 1,000kWh/month, which is 33kWh/day, so going 3 days on a single Ecoflow battery (90kWh) seems very doable (if I’m figuring it right). Adjusting the AC a few degrees, keeping the blinds closed and not doing washing would stretch that a bit further, and adding a second pack down the road could get me to a week.

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My inverter is on the same wall as my home office, so wiring it up would only take about an hour, a ladder, and ~40ft of Cat5. I haven’t taken the time and effort because it’s hot outside and tracking the stats is not as important to me as it was early on.

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25

It’s all micro-inverters these days!

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Ecoflow claims that 90kWh will power the average home for 30 days. However, each battery is only 6kWh, so in order to get to that 90kWh, you’d need a combination of 15 batteries and 3 inverters. That’s a lot of real estate, plus you’re looking at probably close to 2,000 lbs. That’s the size of a small car. Plus the $40,000-50,000 upfront cost.

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With two batteries, we can’t get our house through the night with everything running, and we only put in enough solar panels to cover about 80% of our usage by by-back. Like you our most expensive time of year is midwinter. Our best plan looks like it’s actually a nights free plan, which is what we just switched to. Even with that, there’s a minimum usage base rate and a delivery charge, so as long as we’re on the grid we never pay nada.

With the nights free plan we get no credit for by-back.

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Thanks. Yeah, I just re-checked the website on the capacity of each pack. There’s definitely something I’m getting wrong in my usage calculations if 90kWh can power a house for a month. Even puffery doesn’t account for the discrepancy.

Maybe I’m confusing kW with kWh, but my electric bill definitely says kWh for the usage stats.

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I take it Mrs. T is not like Mrs. Hawk, needing the temperature in the house nearest to 40 degrees F as she can get it.

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30

I think that number is factoring in some amount of solar generation connected to the batteries. Still a pretty outlandish estimate for a whole house, though.

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31

This changes as you get older. Our thermostats are creeping upward.

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32

I used to think that. That she was just a “woman of a certain age”. But that never changed. I think she’s just cold, cold, cold.

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I used to do 68* now I’m comfortable at 72*.

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Yeah, I’m not sure how they’re figuring that, but this is what you’re looking at for 90kWh in batteries:

image

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35

I keep my place at 76 or, as it’s known in Limeyland, “a scorcher!”

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Ours is up to 73-74 in summer, 68 in winter but with a down comforter.

I find myself wearing a sweater around the house in July with the thermostat at 74, but I like wearing sweaters.

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My guess is either, or a combination, of replenishing some capacity every day via solar and only running essentials (refrigerator, water heater, certain other circuits).

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I’m freezing my ass off at 72. Mrs Hawk is complaining about how hot it is at 60.

39

For the 1 partial day of the year when I lose power, I’m just going to stick with my noisy outside but quite inside gas generator. Now if things change and the outages happen in a greater frequency, I might be forced into reconsidering my options.

40

I suspect Waldo is right, and backup is the key word there. For our battery system, it kicks in only when the solar charging goes below usage. At that point, the excess goes to recharge the battery usage from the night before, and once that’s done the excess power goes to the grid. On a sunny day, we’re usually sending power to the grid by mid-afternoon after the batteries are recharged.

If there’s a storm warning, if the batteries are not already recharged, the Tesla batteries will actually recharge from the grid which is pretty cool. With the batteries you can watch all of it from a phone app.

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