One of the biggest misconceptions about solar is that you’ll be able to go off the grid entirely once solar panels are installed. In reality, because of the way solar power is generated and how it’s typically used, most solar homes continue to use energy from the grid, and the savings can vary widely depending on factors like state regulations and your own patterns of electricity usage.
Only a fifth of all solar residents produce more solar energy than they consume, reaching the goal of matching household energy consumption to solar production.
To learn more about solar savings, Sense analyzed data from 1,800 homes across the country to track their solar production and energy usage with the Sense Solar energy monitor. The data showed that the homeowners offset 67 percent of their homes’ electrical bill, on average, and saved $1,075 annually, but the savings were higher or lower depending on where and how people live.
Sense data showed that more than half (55 percent) of the electricity generated by solar panels goes back to the utility grid, on average, with less than half (45 percent) directly used to power the home’s day-to-day needs.
Most homes don’t use all their solar energy during the day, so the excess is sold back to the utility, but then they need electricity from the utility in the hours when solar production drops in the morning, afternoon and evening.
This pattern is referred to as the solar duck curve. Solar production typically peaks at around noon when the sun is high in the sky (with higher peaks in summer than winter).
But energy usage increases at different times in the day: in the morning, when we get up, make our coffee and take showers, and a second peak starting in the late afternoon and evening as we cook dinner, turn on lights, and stream videos. The way we live our day-to-day lives creates a mismatch between solar production and energy consumption.
You can get more from your solar production by understanding your family’s energy patterns and shifting energy-intensive activities to peak solar times or using a battery to store energy from peak times for use later.
Dishwasher or washing machine loads can be scheduled in the middle of the day when solar production is highest. Instead of cooking in the evening, take a lunch break that includes using your oven and stove. In the summer, you can set your air conditioner’s thermostat to cooler temperatures at mid-day, then adjust upward toward evening.
If your family drives an EV, you can also make adjustments that will impact your utility bill. Charging an electric vehicle uses a lot of electricity. For instance, it takes 50-100 kw to charge a Tesla. Scheduling EV charging during the day when solar production is highest, rather than waiting till evening, will substantially reduce your utility bill.
Smart EV chargers like Zappi from My Energy and JuiceBox from Enel X can adjust charging to match solar panel production. They charge when the sun is at full power and throttle back when night falls or clouds hide the sun. They’ll also pause EV charging when other appliances are in use inside the home.
Another factor to consider is how much your utility pays for unused solar electricity that’s flowing from your solar panels back into the grid. State regulations determine the solar homeowner’s pay-off.
Most states mandate that utilities pay residents for their solar power at the same rate they charge for electricity. This approach, called net metering, means that the solar duck curve doesn’t affect your savings. In essence, you’re able to bank your solar power during peak times by selling it back to the utility, then draw on the utility to power your usage when solar production drops at the same cost.
The remaining states use a variety of pricing methods that can reduce payback on solar by allowing utilities to buy back solar power at a lower rate than they charge for electricity. If your utility uses time-of-use (TOU) rates, shifting more energy-intensive activities to times when your solar power is abundant will save you money since rates tend to rise later in the day.
To get the most from your investment, do your homework. Check your utility’s website to find out how much it pays for unused solar power (and you can find a U.S. map of net metering policies here).
Battery storage is still a premium option, but the prices are dropping significantly every year. In areas with rolling brownouts or downed power lines from storms, solar storage can get you through without an interruption.
Storage can be useful, also, if you tend to use a lot of electricity when solar generation is low and can’t move those activities into peak solar times. Batteries can store your solar energy until you need it in hours when the sun doesn’t shine.
With this option, do your homework to analyze the potential payoff of an investment in battery storage. Also, a handful of states offer incentives for battery storage so check your state’s website to find out if yours is one of them.
You may find that battery backup is the answer or that simply shifting your activities will help you get more from your solar investment. With careful analysis and smart decisions, every solar homeowner has the potential to reduce his or her reliance on nonrenewable energy sources.