Carol McGarrySolar can be a significant investment, but is it a good investment for your home and lifestyle, and how can you make it pay off the most?
Sense recently analyzed data from 1,800 Sense Solar homes to try to answer those questions. In this article, we’ll highlight our findings, share advice and take a deep dive into a Sense Solar home — with insights that will inform your decisions — whether you are getting solar for the first time or living in a solar home already.
Key insights from Sense's data:
- Most homeowners use less than half of their solar power directly and need to feed the rest back to the grid or invest in battery storage.
- Sense's research found surprising variations in solar payoff from state to state.
- Since many states allow utilities to buy back solar power at a lower rate than they charge for electricity, where you live can make a big difference in the payoff from your solar investment.
- How people use energy in their home matters, too; homes that use most of their energy during peak solar hours can maximize their solar investment.
- 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.
How You Live Matters
Most solar homeowners produce more solar energy in the middle of the day but need to use energy throughout the day and evening. As a result, Sense data showed that more than half (55%) of the electricity generated by solar panels goes back to the utility grid, on average, with less than half (45%) directly used to power the home's day-to-day needs.
This mismatch changes depending on the season. In the typical home, the highest energy usage does not coincide with peak solar production. In the summer, solar production peaks between noon and 1 PM, while energy usage peaks hours later at about 6 PM. In the winter months, solar production is lower and there are two, smaller peaks in energy usage in the morning and evening. Here are the “duck curves” for 400 Sense Solar homes, showing their solar production and energy usage in the summer and winter.
Pay Attention to Your Utility’s Payback
Since there’s a good chance that you’ll sell back your solar power to the utility, it's important for homeowners to find out how much their utility will pay them for the power they don't use that goes back into the grid. In states with net metering, where utilities pay for solar energy at the same rate as they bill for electricity residents don't need to worry about timing their usage. In states that don't require net metering, residents are typically receiving lower payback rates on their solar power from their utilities and should look for ways to shift their electricity use to peak solar production times.
Tip: Do your homework before installing a new system. Assume that you won't use all your solar production and research your utility's payback rate on unused solar power (see map of state policies here), as well as both federal and state incentives. The Solar Energy Industry Association's website is a good place to start.
Adjust Your Energy Use to Match Solar Peaks
Understand your home's energy usage patterns and adjust them to match your solar production. Solar homeowners whose utilities don't offer net metering can reduce their electrical bills by scheduling energy intensive activities during peak solar hours.
Tip: Some appliances can be scheduled more frequently during peak solar hours, including your washing machine, dryer, oven, dishwasher, and stove. Charging electric vehicles (EVs) consumes a lot of power, so solar homeowners should make it a priority to charge their EVs during the day using their solar power.
Where You Live Matters
Where do solar panels pay off the most for homeowners? Among states with the most solar homes, residents in sunny Utah and California gained the most from their solar investment. Utah residents offset 84% of their utility bill, while Californians offset nearly 75% of their bill. Arizona residents have a lot to gain, too. They generate solar power equivalent to 66% of their average utility bill.
Surprisingly, residents in Northeastern states are among the bigger gainers with solar: New Hampshire (76%); Vermont (70%); Massachusetts, New York and Pennsylvania (67%); and Connecticut (66%). While these states receive less sunlight, solar panels are more efficient at lower temperatures, giving cooler states an edge in solar production. By contrast, residents in cloudy Washington only offset 52% of their utility bills with solar.
Making Your Solar Home Pay Off to the Maximum
With some planning and changes in your habits, it’s possible to move your usage to coincide with solar production. For inspiration, we turned to Sense customer Mark Hovis, who shared his solar home profile with us.
Notice how the peaks and valleys coincide? That’s no accident. Mark has cracked the code on load shifting, a technical term with practical implications for every solar homeowner. We talked with Mark recently to find out how he did it.
Mark has two EVs and they provide the secret weapon in his mission to use up every watt of his solar power. They are powered by an eco-smart EV charger. He uses the Zappi from My Energy, which adjusts EV charging to match PV production, boosting charging when the sun is at full power and reducing it when clouds move in or night falls, for instance. The JuiceBox from Enel X operates on a similar principle.
Of course, Mark needs energy to run the rest of the electrical appliances in his home, too. His heating sources are a combination of a pellet stove that turns on at 5 AM then turns itself off at 10 AM when the solar arrays kick in to power his geothermal heating. At about 5 PM, the geothermal turns back off and the pellet stove takes over until bedtime. Mark lives in North Carolina, where pellets are a byproduct from the local furniture industry, making it an abundant and local energy source when solar power wanes.
Mark and his family optimize their use of the washer, dryer, and cooking around solar production. If the washer or dryer are on, the eco smart charger pauses before resuming its EV charging. And when there is extra sun, the charger delivers up to 32A to speed up charging.
Says Mark, “One of my biggest goals is to load shift and Sense is my number #1 tool to do that.”
Mark is playing the long game, when it comes to thinking about renewable home energy. He is betting on battery innovation that will bridge the gap for most solar homeowners. Said Mark, “Right now, battery chemistry limits the number of charging cycles they’ll handle, but when Tesla introduces a million mile battery for their robo taxi fleet it will have huge impacts on home energy as well.”
Mark sees three categories of “batteries” in solar homes: EVs have the largest storage potential, followed by mini-battery storage and the hot water heater as a still smaller energy source.
He looks forward to vehicle-to-grid (V2G) and vehicle-to-home (V2H) energy flows. Mark said, “If the EV can act as a battery in a solar home, the average future EV will be 60 kWh. With two EVs, you have 120kWh. In a typical home that uses about 35kWh per day, two EVs would give you four days of energy to run your home, depending, of course, on how much you drive. In a worst case scenario, you drive your mobile energy source to store it up and bring it back.”
Mark comments that “Tank water heaters are a great battery, storing 4-5kWh daily. With just a little IFTTT, you could program your solar water heater to heat only when the sun shines and release that energy back to the home in the evening.” He figures that you really only need enough extra storage to address the four-hour gap without solar power in the evening to beat the duck curve and eliminate peak load strains on the grid — a gap that a combination of power from EVs, battery backups and hot water heaters, in combination, can bridge.
Mark points to trials by Mitsubishi and Nissan of residential solar-plus-storage EV charging in the US, Japan and Europe that are pushing innovation forward.
A word of advice from Mark: “You need to understand the duck curve!” We couldn’t agree more. Knowing your own home’s energy patterns will inform your efforts to shrink your home’s energy footprint. Mark has a professional background in precision engineering, and his proactive approach reflects his precise understanding of home energy. But we were even more inspired by his passion about our shared future on the planet.
Said Mark, “In my vision, I want to solve global warming. It will take all hands on deck, that means left and right, everyone has to work to beat this thing, because it’s huge.” Mark added, “Solar is actually a conservative idea, and there was a time that Teddy Roosevelt and Margaret Thatcher supported it.”
We’ll leave the last word to you, Mark, and thank you for helping to point the way to a renewable future for every home.
Ready to take the plunge on solar? Click this link to learn more about Sense Solar.
