Explained: Green Mountain Power’s Bring Your Own Device program
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Energy storage is key to a reliable clean energy future, but in practice, there’s been some major barriers to getting batteries up and running. One of the biggest obstacles is cost: batteries, both small and large-scale, require quite a bit of upfront investment.
While many utilities use this as an excuse to avoid storage altogether, Vermont’s largest utility, Green Mountain Power, is embracing it, through its innovative Bring Your Own Device program. First launched in 2018, the program provides cost incentives for homeowners to install battery storage, while giving the utility access to a whole new network of stored energy to help relieve stress on the grid.
It sounds like a win-win; homeowners get to install solar batteries at a fraction of the price and Green Mountain Power gets to keep its operating costs low. But due to its limitations, the Bring Your Own Device program might not be the right choice for all homeowners, even if it does cut down on the upfront investment needed for a solar battery.
There are two incentives for you to choose from under the Bring Your Own Device (BYOD) program: the "Back Up Only" incentive and the "Solar Self-Consumption" incentive. The incentive you choose determines the amount of your rebate. The incentive you choose also depends on how you plan on using your battery. Let us explain.
Under the Back Up Only BYOD incentive, you must install a qualified battery system on your property for the sole purpose of using it during a power outage. It cannot be used for anything else - for instance, you cannot charge the battery with solar panels during the day and then use that stored energy later that night to power your appliances.
Not only are you limited to using the battery solely as a backup power source, you also are giving GMP permission to use the energy stored within your battery during ‘Peak Events’ for 10 years. GMP describes a Peak Event as “a period of time in which customers collectively use the most energy”.
During those peak timeframes, which are said to occur an average of five to eight times per month for three to six hours a time, GMP can use the energy stored within your battery to alleviate stress on the grid.
There are two incentive rates available based on how many hours you allow GMP to discharge your batteries for:
Those who choose the Back Up BYOD option will receive compensation as a one-time, upfront payment.
You also get to choose how much of your battery you give GMP permission to use, in kilowatts (kW). That means, if you purchase a battery with a power output of 7 kW, you can choose to enroll only 5 kW for a lower incentive than if you had enrolled the full amount.
To figure out how much your incentive would be, multiply the number of kilowatts you are enrolling by the incentive rate that corresponds to the amount of time you are giving GMP access. So let’s say you enroll 5 kW and allow GMP 4 hours of access, you would get an incentive of $4,750. That’s just about half the cost of a typical solar battery installation!
The Self-Consumption incentive option is great for homeowners who want to install a battery, but don’t want to be limited to only using it as backup power.
By choosing this option, you can, as the name suggests, use your battery in Self-Consumption mode. So if you have solar panels, you can store excess solar energy produced during the day and then use the stored energy to power your appliances at night.
While this option gives you a little more freedom with how you use your battery, there is still one limitation - you must use the power stored in your battery for the entire duration of all Peak Events.
Those who choose the Self-Consumption BYOD option will receive a one-time, upfront incentive of $850.
$850 is a much lower incentive amount than what you would get if you allowed GMP to access your battery through the Back Up Only option, but you're not as limited in how you can use your battery.
Only certain batteries are eligible to receive the BYOD incentives, including:
It's a little unclear what battery models the program does and does not cover. For example, GMP states the Tesla Powerwall 2 is eligible, but it doesn't say anything about the newest version of Tesla's battery, the Powerwall+. It's also unclear if all sonnen-branded batteries are eligible, or if only one model qualifies.
We have reached out to Green Mountain Power for confirmation, but have yet to receive a response.
Beware of fees! GMP states that some equipment may come with an additional set of manufacturer and network fees. The only thing we could find on its website is that any system that uses StorEdge inverters will have an additional monthly fee of $6.67 added to its bill. We’ve reached out to GMP in hopes of receiving a full list of these fees.
So far, we’ve covered the most basic terms for the BYOD program, but there are a few others that you need to keep an eye out for, including access requirements, what happens if you sell your home, termination procedures, and privacy matters.
In order to participate in the BYOD program, you need to ensure that you have a steady internet connection so GMP can properly monitor and manage your battery system. GMP will send a notice if there is a communication issue, and it must be resolved within 30 days of receiving the notice.
If the issue is not fixed within 30 days, GMP will charge you $12.70 per kW enrolled in the BYOD program per month until it’s been resolved. For example, if you have 5 kW of your battery enrolled in the BYOD program and GMP cannot access it after 30 days notice, GMP will charge you $63.50 per month until the battery can be accessed again.
In order to participate in the BYOD program, you must own the property where the battery is installed. If you sell the property before the end of the 10-year program term, you can transfer the agreement to the new property owner.
However, if the new homeowner does not want to take over the agreement, you have to terminate your enrollment and pay the associated fees.
If you decide the BYOD program just isn’t for you, or you sell your home and the new owner doesn’t want to overtake the agreement, you will have to pay GMP back for the incentive the company provided you. What you owe will depend on how many months are left in the lease agreement and which incentive (Back Up Only or Self-Consumption) you chose.
Let’s take a look at two examples:
Scenario 1: You decide to opt out of the Back Up Only BYOD program with 30 months remaining in the term, and you enrolled 5 kW that GMP can use for 3 hours at a time.
(30 months remaining/120-month term) * $850 per kW = $212.50 per kW enrolled owed to GMP
$212.50 * 5 kW enrolled = $1,062.50 total owed to GMP
Scenario 2: If you opt out of the Self-Consumption BYOD program, you would simply divide the number of months left in the term by the total 120-month term, and multiply it by $850:
(30 months remaining/120 month term) * $850 = $212.50 total owed to GMP
Privacy is something that most homeowners probably wouldn’t think twice about when they’re applying for a battery storage incentive, but it is something to keep in mind with this particular program.
When you sign up for the BYOD program, you consent to disclose your energy usage and consumption data, as well as some personally identifiable information to help with monitoring, reporting, and programming for GMP. You also consent to this information being shared with third-party vendors.
As long as your battery system is installed alongside a new or existing solar panel system, and it will be 100% charged using the solar panels, you can claim the 30% federal tax credit when participating in the BYOD program. The battery does not have to be connected to solar panels to receive the tax credit.
Exactly how much you spend on your battery installation will depend on the battery system (brand, size, how many batteries, etc.), your installer, and which incentive you choose. With that said, let’s go over a few examples so you can get a general idea of what to expect.
We’re going to look at the Tesla Powerwall as an example. Say you decide to enroll 5 kW of a Tesla Powerwall, which costs about $11,500 for the equipment and installation, in the Back Up Only incentive.
If you choose to give GMP access to the battery for 3 hours, you would get an incentive of $4,250, which would bring your total Powerwall installation cost to $7,250. If you also qualify for the federal solar tax credit, the cost would drop even further, to about $5,705. Not bad!
If you gave GMP access to your battery for 4 hours, the cost for the battery and installation would fall to $6,750, and down to $4,725 after the tax credit.
As we said earlier, the value of the Self-Consumption incentive is much lower than the Back Up only incentive options.
For the same Powerwall battery, you would only receive an incentive of $850. That would mean the total cost would be $10,650, instead of $11,500. When you include the solar tax credit, it would cost about $7,455.
If you really want to install battery storage with your solar panels, then you should definitely consider Green Mountain Power’s BYOD program.
However, from a financial perspective, pairing a solar panel system with solar batteries doesn’t really make a whole lot of sense, since GMP offers full-retail net metering to its solar customers. All this really means is that installing a battery doesn’t offer any additional savings on your electricity bill.
You see, the average solar panel system in Vermont will pay for itself in a little less than 10 years, thanks to GMP’s net metering program. When you add a battery to that, it will take about 15 years to pay for itself, even with the BYOD incentive and federal tax credit considered. While this isn’t a horrible payback period, it’s still longer than if you just install solar panels on their own.
But if having access to backup power in the event of a grid outage and maximizing the amount of solar electricity your home uses is important to you, then the additional cost for a solar battery could be a worthwhile investment.
The best way to figure out if solar-plus-storage is worth it for your home is by using our solar savings calculator. Not only does it give you an idea of how much solar can save you, but it also shows you how much your investment is impacted by including batteries with your installation.