For a homeowner who recently installed a solar PV (photo-voltaic) system, a critical question they should ask is, “Is it working?”. One way to know that your solar panels are producing electricity is to review your monthly bill and compare it to the same month last year.
Most electric bills include information on how much energy was used up to 13 months ago, so with a relatively quick glance at the first few bills after installation, you should be able to determine approximately what you have saved compared to the same month last year.
But if you have changed your habits and upgraded to newer, energy efficiency appliances, your total usage may have gone down, which could look the same on your electric bill as a good working solar system, but there might actually be something wrong with the solar.
Or, perhaps you installed a cold climate heat pump to help heat your house, or you bought a plug-in car and you are using a lot more electricity than you did a year ago. The solar might be doing a good job of offsetting the new heat pump, but the electric bill hasn’t changed much.
Almost every inverter manufacturer today provides some way of telling you how much energy was produced by your solar system today, last week, last month, and since you first turned it on. The inverter is the device that converts the DC (direct current) from the solar panels into AC (alternating current) that we use in our homes.
Often you can get this information directly from the front panel on the inverter, assuming it is readily accessible. If you are using micro-inverters (a small inverter for each solar panel), they are mounted on the roof or with the solar panels themselves and are not very accessible.
Without a display, micro-inverter manufacturers had to come up with another way to show production data, both to prove that it was working, and to help debug problems when they arose.
Since Internet access is available at a large percentage of homes with solar, these manufacturers drove the trend to make data monitoring available online. With just a web browser, a homeowner can get information about their solar production from their laptop or computer whether they were at home, at work, or traveling. They don’t need to be in front of their inverter and they don’t need to rely (or trust) their utility company bills.
Most manufacturers of solar inverters today have an online data monitoring option available. This type of data monitoring will often allow you to compare your systems production today with the same day last year, or two years ago, or the production of one month compared to another. Some systems even allow monitoring of the production of each solar panel individually.
If you are looking into a solar electric system for your home or business be sure to ask the installer about the monitoring options so you will be able to answer the question, “is it working”? Or even better, “how well is it working”?