COLCHESTER — Green Mountain Power and Waterbury solar power company SunCommon this month announced a partnership that will allow GMP customers to store solar electricity for use during a power outage — by taking advantage of the power company’s existing partnership with Tesla Motors Inc.
Since early this summer, GMP has been offering customers the Tesla Powerwall battery to store electricity to protect their properties during power outages. According to the Colchester company, an early Powerwall customer in Lincoln kept a household running for 14 hours this summer after an outage following a storm.
Now officials from both GMP and SunCommon say that, through their new partnership, homeowners can have solar arrays installed and install a Powerwall battery as backup with no upfront costs. They say that customers would see savings in their electric bill that would cover the $37.50 monthly fee for the battery and the finance charges for the solar array.
GMP spokesperson Kristin Carlson said the two companies started talking this summer about a program that was officially unveiled on Sept. 14.
“One of the real exciting opportunities with battery storage is pairing it with solar, so that people can turn that solar into a backup power source,” Carlson said. “It just seemed like a really great fit to streamline the offerings so people can really fully leverage their solar with the latest in battery technology.”
SunCommon spokesperson Emily McManamy described the process a potential solar customer would go through with her company. A homeowners that contacts SunCommon would first speak to a “solar advisor,” then a company representative would visit the property to assess the possibilities for siting arrays and examine power bills to understand the electricity need. And eventually SunCommon would design a solar system specific to the home’s needs and site.
The home array produces power that goes back into the power grid, enough power to equal the home’s annual usage. Through net-metering and solar credits, the homeowner buys the solar array instead of paying GMP bills.
“The way that we size our systems is we look at your annual usage, and we size and design a solar system to meet those annual needs, with the goal being at the end of the year your utility bill is zeroed out,” McManamy said. “Say your monthly power bill is $100. We size a solar system to offset that bill. Instead of paying a utility company in perpetuity, you’re shifting the payments to a solar system you own.”
The new partnership allows SunCommon to design a solar array — of either ground- or roof-mounted, depending on the site — that can also cover the cost of the Tesla Powerwall, but only if they act before the end of 2016.
“If they choose to do the Tesla Powerwall this year, they can choose to cover the cost with the solar credit,” McManamy said. “They’re able to roll that cost into their solar payment.”
McManamy also noted that homeowners who act this year will benefit from more favorable kilowatt-per-hour solar credits that expire on Dec. 31, with the difference amounting to $1,500 over the course of Vermont’s current net-metering program.
The actual cost of installed solar arrays can vary widely, McManamy said, from $10,000 all the way up to $50,000, depending on the size and power usage of a home. SunCommon has an agreement with the Vermont State Employees Credit Union, or VSECU, to provide what she calls a good deal on loans.
“We offer no-upfront-cost, low-interest financing through VSECU,” McManamy said. “A popular one is a 12-year, 2.99-percent one.”
She said the cost sounds expensive, but also said homeowners are not going to be paying more than they do now — the key is a monthly cost in line with existing power bills.
“If you’re used to paying $100 a month, then we want you shifting that $100 a month toward a solar system, so it mirrors and replaces your utility bill,” McManamy said.
McManamy said homeowners have other reasons for going solar with SunCommon or other companies, a “sense of predictability” for their power bills, with a set monthly payment replacing seasonal spikes; “a sense of self-sufficiency”; and, in GMP CEO Mary Powell’s words, the desire to help Vermont and the nation “move away from the antiquated bulk grid, to a cleaner and more reliable energy system.”
Some, including McManamy, choose to add a heat pump — which can both heat and cool a home — to the mix, as well as a solar array and a Powerwall, to further reduce their home energy costs and consumption of fossil fuels.
“Last summer I added a heat pump,” she said. “I no longer need to run my oil-burning furnace to heat my home. So my solar array is covering my power needs and my heating and my air conditioning needs.”
One thing McManamy said homeowners shouldn’t worry about is selling a home after a solar array is added, even if a loan is not paid off. She cited a national study indicating that arrays add value, and that homeowners typically just pay off solar loans when they close a sale of their properties.
“Basically what homeowners are doing is factoring in the value of the solar system into their sales price and paying off their loan at the time of sale. It is an asset you have purchased and installed in your home,” she said. “The beauty of this is when people market their homes they can say ‘Free power.’ With a heat pump, when I market my home I can say free power, heat and air conditioning.”