PV panels contribute to bill savings and environmental security

by Alan Yonan Jr.| July 6, 2021

I’m a bit of a data geek so one of the first things I did when I considered putting PV panels on my home in 2018 was to look at a solar resource map of Oahu to see how the intensity of sun in my area measured up.

The good news was that the neighborhood where my family and I live gets some of the best sun on the island. That meant that even with the limited roof space on our townhouse we would still be able to generate plenty of electricity from our PV system.

Although our transition to solar went smoothly we still had to adjust to reading our new electricity bill. Our old bill was pretty straight forward — it went up and down depending on how much electricity we used. With PV panels, however, you also need to account for amount of solar energy the PV panels are collecting.

The output of PV panels can fluctuate depending on the season (more sun in the summer and less in the winter), as well as micro-weather events (an unusually rainy month). With two variables in the equation — solar production and electricity usage — customers with PV panels can see their electric bills vary markedly from month to month.

In the first full year we had our PV panels our monthly electricity bills ranged from a high of $54.54 to a low of $7.74. There also were many months where we paid the minimum charge of $25. It wasn’t surprising that the high bill occurred in February, when the monthly solar production from our panels was the one of the lowest of the year, and our electricity consumption was above average. Our low bill was in July, when the solar production was very good, and our consumption was about average.

When a responsible PV company makes its sales pitch, the company will consider the solar radiation in the customer’s area, their typical electricity usage, and the technical specs of the panels so they can size a system that will approximately cover the customer’s electricity energy needs when averaged out over a year.

Because our PV system was sized based on our past electricity consumption, we knew that we should try to stick to our historical usage, which averaged about 600 kilowatt hours per month. I wanted to avoid the urge to suddenly start running our air conditioning at all hours of the day and night or leaving lights on just because we were getting “free electricity” from our solar panels. That can be an issue for some folks who go solar. They dramatically increase their electricity usage after the panels are installed and then wonder why their bill hasn’t dropped as much as they thought it would.

In our house, fans get the job done for cooling on all but the hottest days. And even though we live in a townhouse there is plenty of space on our lanai to air dry our laundry. Plus, clothes hung on the line smell fresher and last longer than ones tumbled in the dryer.

We’ve been happy with our PV system since it was installed a little more than three years ago. In the beginning I would log on to the PV panel manufacturer’s website every day and watch in real time as the clean electrons produced by the “power plant” on our roof flowed into our home. Nowadays, I check the website less frequently but it still amazes me that the simple process of sunlight hitting a silicon wafer on our roof is producing the electricity we use to cook our food, watch television or run the dishwasher. I’d recommend that customers with rooftop solar monitor the system’s output regularly — especially after outages or inclement weather — to make sure it’s producing energy as it should.

It feels good to be helping Hawaii get off fossil fuel, while saving money on our electric bill. At our current pace of bill savings, our PV system will be paid for in less than two years from now. That will be a big win for our household balance sheet as well as our contribution to Hawaii’s environmental and energy security.

Alan Yonan Jr. a senior communications specialist at Hawaiian Electric Company.