Houston Solar Panels 2022 version

Having bought solar panels myself a couple of years ago, and realizing that the city permit database could be used to find most installations, I decided that it would be interesting to look at the recent history and a few other facets of residential solar panel installations.

The first step is to download the structural permit data as a CSV file from the city open data website.. This file is no longer available, so I now download the data from the new site and clean it up. Details may be found on my github site. The code for cleaning up the older data is in the file Clean_old_City_permits.Rmd on that same github site.

Grabbing the correct records

As far as I can tell, Solar Panels are designated as such in the Description field, and nothing else. So a simple filter on “Solar” should suffice to capture all the installation permits. In more recent records, batteries are also flagged with tags like BATTERY, BATTERIES, LITHIUM, LI-ION, or POWERWALL. Additionally, since about 2017 but more consistently in recent years, the number of panels has been noted, so I can use that as a way to estimate added capacity.

And there are 2 installations of solar roof tiles.

Time series

So let’s look at the growth in panels over time. We’ll consolidate to monthly numbers to make the plot look descent.

The doubling time looks like about 2 years.

Let’s take a look at batteries

Hmmm…. looks like a big jump not long after Valentines Day of 2021. Why would that be?

Interestingly, we see no jump in generator installs, which I really expected to see. Which makes me a little suspicious that there is something wrong with the data, but I don’t know what that would be.

Look at amount of power capacity

We will use the number of panels (where noted) to get an idea of how much kW capacity is being added.

At the rate capacity is being added, assuming an exponential increase in installs with a 2 year doubling time, in about 8 years the installed capacity in the city would be the equivalent of an average Natural Gas power plant.

Let’s look at the distribution by Zip code

Surprisingly the Houston Arrow does not appear on this map. That is a bit of a surprise. Note that 77048 is dominated by a property of apartment homes that were built with a large solar array.

Solar Panel Installations by Zip Code
2014 - present
Zip Code	Number of Installations
77072	136
77048	119
77045	113
77099	108
77008	106
77009	104
77085	104
77088	103
77034	97
77025	90
77075	89
77047	83
77035	81
77007	79
77096	79
77339	75
77021	74
77016	73
77077	70
77080	66

Let’s combine solar panels with assessments

Interestingly, it is clear that solar panels are not just for the wealthy. The median value of homes with panels is pretty close to the median value of homes in general. I used the 2021 HCAD total market value for the value for each home.

There are some differences however. It appears that it roughly twice as likely that a house worth over $1,000,000 will have solar panels than a house worth less than that.