This is the second in a series of articles following one participant’s experience with the U Community Solar program and its effects on her life.
Andrea Brunelle, University of Utah faculty member
You want to know what I love about being a professor? I’m constantly learning new things. I have incredible access to smart people with different backgrounds, training, and perspectives.
The process of getting solar panels has been a fantastic opportunity to continue learning. And, it’s been amazing—as a climate scientist and self-proclaimed environmentalist—to actually learn about solar panels and solar energy and then do something about my carbon footprint.
My previous knowledge of how solar panels work was pretty hazy. In my mind, it was sort of like photosynthesis, just one of many miracles associated with the energy from the sun!
Kate Bowman from Utah Clean Energy outlined how solar energy is installed and what happens at each stage. I found it super helpful, so I wanted to share it with you. It’s clearer to me now. But it’s similar to when you are in class and the teacher asks if you understand, and at that moment in time, you do. But if asked to explain it later, you might not be able to do it.
Once you get this all straight, brace yourself to hear about my experience getting hooked up to the grid! I’ll tell you all about my net meter, my Enphase monitoring system, and the similarities of watching solar panels make energy to watching plants grow in your garden (only with digital evidence!). Stay tuned.
Solar Installation Steps
1) Pick your solar photovoltaic panels.
There are three different panels offered through U Community Solar. You can choose the ones you like best based on price, the wattage of the panel (how much energy it produces), or aesthetic appeal. Some of the panels are blue with silver frames and others are black with black frames.
In order to generate enough electricity to power a home, multiple panels are installed together, which is called an array. You can install multiple arrays to take advantage of smaller or segmented roofs. For example, if you only have limited, south-facing roof space, you can install a second array on the west-facing roof.
Panels create electricity through the photovoltaic effect in which sunlight causes electrons in the panels to absorb energy and generate an electric current. Solar panels produce direct-current electricity, which flows unidirectionally, but most homes are wired for alternating-current electricity, which means the direction of the current reverses back and forth. To make the panels compatible with the home, Enphase microinverters are needed.
2) Install Enphase microinverters.
Inverters are needed to convert the direct-current electricity from the panels to alternating-current electricity.
Before microinverters became common, string, or central, inverters were used, but they had several downsides. String inverters provide less flexibility when it comes to the size of a solar-panel system because they must be connected to a minimum number of panels based on the size of the inverter and can’t be connected to too many panels. For example, if you had a string inverter that could serve 6-10 panels and your roof can only fit five panels, it wouldn’t work. Another downside of string inverters is that shading on one panel would impact the whole string. For example, if a tree casts a shadow on a corner of one panel during the day, it would significantly impact the production of all the panels.
Microinverters are now more commonly used for homes because they are more modular and flexible. One microinverter is attached to each panel, allowing you to install a huge array or just a single panel. They’re rated for temperatures from -40 to 149 degrees Fahrenheit, so they can withstand cold and snow or summer heat. Microinverters also minimize problems with shading. If one panel is shaded, the rest of the panels keep operating at 100-percent capacity.
3) Wire the panels to your breaker box.
The panels need to be connected to the breaker box so that they can deliver electricity to your house. The wires are usually run into the attic near the panels, through the attic and back outside to the breaker box. The panels and all the associated metal hardware on the roof is grounded for safety.
Electricity from the panels feeds into the breaker box, and the solar energy will be used to feed any breakers that are currently using energy. If no electricity is needed or the panels are producing more power than is currently needed, the excess electricity is sent to the grid through your electrical service, where it is fed to the nearest source of electricity use (probably a neighbor).
4) Connect to the grid.
U Community Solar only offers grid-tied systems, meaning you can use the electricity from your solar panels as well as grid electricity so you’re not relying on the panels for 100 percent of your usage.
It is possible to install an off-grid system, but it is usually significantly more expensive. Batteries are needed to store energy for use at nighttime, and the batteries are expensive and take up a lot of space.
With a grid-tied system, you have the option to install more or less solar depending on your available roof space and your budget.
5) Start saving money: Electrical and net metering.
Net metering is a billing mechanism that credits solar energy system owners for the electricity they add to the grid. A regular electrical meter measures the amount of electricity that is flowing into the home from the grid, while a net meter counts electricity coming from the grid and the electricity that is sent back to the grid. Solar users are charged for the net difference between these two at the end of the month.
All customers, including solar customers, pay a monthly customer charge and minimum bill. This portion of the bill is for fixed costs that the utility company incurs no matter how much electricity you use, including the cost of maintaining the grid. For example, if a person without solar panels went on vacation for a month and their house used no energy, they would still pay this minimum amount (currently about $7 a month), and if you cover 100 percent of your electrical use with solar panels, you will still pay about $7 a month.
You receive net metering credits for each kilowatt-hour of electricity you produce. If you use less electricity than you produce, you can roll the extra kilowatt-hours of credit over to the next month until March 31 each year, when all of your unused net metering credits expire.
6) Watch your panels make energy.
The Enphase Envoy monitors the output from your microinverters, and you can see how much electricity the panels are producing through a password protected website (like this one).
Real-time data lets you know if the panels are working correctly. If a branch falls on a panel and is blocking sunlight, you’ll get instant feedback that something is wrong. Your solar installer has access to this information, too, so if they notice something wrong, they will coordinate with you to come check on it.