There are a couple of things to consider as you read this.
Eli Hartman/The Texas Tribune
Texas ranks third in the country in electricity generation from small-scale solar, including rooftop solar, trailing California and Arizona, according to the Energy Information Administration. (The federal office defines small-scale solar as systems with capacity of less than 1 megawatt.)
On a per-capita basis, however, Texas ranks 20th, which indicates that there is a lot of room to grow. How much room is difficult to say, but a good way to frame it is that the state’s generation from small-scale solar last year was equivalent to about 1% of the total from large power plants.
The state has the technical potential to cover more than 30% of its electricity consumption with rooftop solar, according to a 2018 paper from the National Renewable Energy Laboratory. I’m cautious in citing this figure because the underlying data is more than a decade old, and because technical potential is usually a lot more than markets or consumer preferences will bear. An official at the lab tells me researchers there are working on an update to this research, which may be available next year.
In recent years, Texas has increased its electricity generation from small-scale solar at a rapid pace. In 2023, the state generated 4,337 gigawatt-hours from this category, an increase of 45% from the prior year, according to EIA. Of the 10 states with the most generation from small-scale solar last year, only Florida had more percentage growth, with 47%.
Some of the main drivers of rooftop solar in Texas have been a desire to reduce exposure to rising utility costs and concerns about reliability of the grid, said Ryan Barnett, senior vice president of policy and market development for Palmetto, a North Carolina-based climate tech company whose products include solar and battery storage.
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Another key variable is that the costs of solar and storage have mostly been flat while utility costs continue to rise. A solar system may cost about $20,000, but the savings on electricity bills will cover the costs in less than seven years, according to EnergySage.
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We got rooftop solar panels installed last year, just before summertime. The $20K cost estimate given here is in line with what we spent, and we definitely saved money on our electric bill from the beginning. It saved us quite a bit, given how monstrous last summer was and how much we had to run the air conditioning. But be very careful when reading that EnergySage article, because the savings on our electric bill was more like fifty percent, not the whole thing. That’s partly because the sun doesn’t shine all the time, of course, but that wasn’t a big issue. The big issue was that with temperatures only dropping into the low 80s at night, we’re still heavily using the A/C (easily the biggest part of our electric bill) when the sun isn’t shining. Look at how much your electric bill is daytime use versus nighttime use before you start zeroing out your monthly payments. It’s not going to be what you think.
Also, in a little bit of irony, the mature oak tree we have in our front yard, which has for years provided cooling shade for our west-facing house, is now slightly reducing the maximum capacity of our solar panels, because they’re partly in the shade in the afternoon. I mean, what are you gonna do?
What we could do in order to further reduce our nighttime cost is install backup batteries. Even with the inconvenient shade we have on our rooftop, we generate more electricity than we need during the day. You’ll hear about how with rooftop solar, you can sell that excess energy back to the grid via a process called net metering, and thus save yourself even more money. That only works if your utility uses net metering. As you can see from the map farther down in that last link, that depends on what utility you have in Texas. And sure enough, CenterPoint does not offer net metering. You can’t sell your excess energy back to them, they won’t take it.
That means our next best option is battery backup, to store that excess electricity for later use. That could be used overnight, to reduce our electric bill further, and it could be used during a prolonged power outage, which was definitely something we thought about when doing this installation. The main issue there is it significantly increases the up-front cost, which led us to defer that for a year. We are unfortunately still working through the details on that, which means that we couldn’t take advantage of this setup for either the derecho or Beryl, but it’s what we’re aiming for in the future. I regret to add that by far the best battery option for us was the Tesla product, which doesn’t make us happy but is what it is. You’ll want to do some research on that before you proceed.
There are other options to consider. We have owned some Yeti Goal Zero batteries for a couple of years, and the combination of having them and being able to recharge them elsewhere (mostly, my mother-in-law’s house) while we were powerless meant that we kept the fridge in the house and the freezer in the garage sufficiently cool during each of those outages. There are portable solar panel chargers one can use in conjunction with these batteries as well, although that presents some challenges because everything gets hot, and the batteries are harder to handle and slower to charge when they’re hot. But they were definitely better than nothing. And as noted before, electric vehicles can also help provide emergency power.
That’s a different use case from just reducing your electric bill, but both are things you can do with rooftop solar and some kind of battery storage. Your utility, if you’re not a CenterPoint customer, might make this easier for you. There’s a big up front investment, but the return is clear. It’s worth looking into.
UPDATE: To clarify, while CenterPoint doesn’t do net metering, you can get buy back credits from your electric retailer. They compete on that point, so check to see what makes sense for you.