Green Mountain Power To Offer Tesla Powerwall Starting At $37.50 Per Month

DEC 9 2015 BY MARK KANE 34

Tesla Energy Powerwall

Tesla Energy Powerwalls

Green Mountain Power announced a Tesla Powerwall offer for its customers in Vermont, while also stating that it’s the first such offer in the country.

First shipment are expected in January, as the company intends to pilot the installations with 10 customers in Rutland, the “Energy City of the Future“, prior to going statewide. In total, GMP hopes to get 500 Powerwalls sold/installed over the few months thereafter.

The 7 kWh Tesla Powerwall with 2 kW power output (3.3 kW peak) should provide backup power for homes for 4-6 hours, according to GMP.

“Green Mountain Power is pleased to announce it is the first utility in the country to offer home battery offerings for customers. Under this innovative filing, Vermonters have the option to purchase the Tesla Powerwall battery outright or lease with no upfront cost. The cutting edge battery technology will empower customers to become more energy independent while also allowing the company to reduce peak demand on the system, providing cost savings to all customers. GMP is the first utility in the country to partner with Tesla to offer the Powerwall.”

“The Tesla home battery can be paired with small-scale solar such as rooftop panels to store locally generated energy, or it can be used without solar as a battery to store power from the grid. During a storm or emergency, the battery is able to power essential parts of the home like lights, a refrigerator, and furnace. GMP will partner with customers to utilize the batteries during peak energy times to directly lower costs for customers by reducing transmission and capacity costs.”

GMP President and CEO Mary Powell said:

“This is a game changer that will help fully leverage solar to the benefit of all with cost savings, while empowering Vermonters to generate, store and use energy closer to the home. As Vermont’s energy company of the future, GMP is partnering with customers on an energy transformation that moves away from the 100-year-old grid system, to a new one that is more reliable, sustainable and cost-effective.”

How much it will cost? It depends on the options – there are three and two include battery sharing to store power from the grid:

  1. Customers who share access of the battery will pay about $37.50 a month with no upfront cost, which equals $1.25 a day.
  2. Customers can also choose to purchase the Powerwall for about $6,500, share access with GMP, and get a monthly bill credit of $31.76, which represents the value of leveraging the battery to help lower peak energy costs.
  3. And Vermonters can buy the Powerwall outright from GMP with no shared access for about $6,500.

Tesla said that they will sell the 7 kWh Powerwalls optimized for daily use for $3,000 (10 kWh version optimized for backup applications for $3,500). Tesla’s price includes only the battery unit.  Full details/specs/pricing on Tesla’s full range of “Energy” products can be found here.

GMP is willing to reveal details of what is included in the $6,500 if you contact them, so if there are any Vermonters out there interested, then give them a call…and of course, let us know the details.

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34 Comments on "Green Mountain Power To Offer Tesla Powerwall Starting At $37.50 Per Month"

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Someone out there

I belive Tesla updated that power output number to around 5kW after some criticism


I think they were just trying to make the battery last longer by not using it at once that should be needed over 14-18 hours.
But even the price at $3500/10kwhr is still too high for most of the US.
You’d need time of day or above $.22/kwhr or so to make it pay it’s own way.
To be viable in most of the US they need batteries under $200/kwhr retail.

Interesting. Option 1: $0.178/kWh price difference between peak/off peak would pay for that. However, what is the “shared access” mean? If I can’t full cycle it to gain peak/off peak advantage, then it is just a “backup” device. Then that is too much. If I am allowed to gain the TOU benefit, then it is way to go. Option 2. Sounds like okay plan. However, with a 10 year warranty, it would mean that half of the cost is still paid by the owner for about $3000 over 10 years. Still curious on what “shared access” means. Option 3. This only makes sense if 7kWh per day in TOU difference can pay for the $1.83 per day cost (not counting interest). That is a $0.26/kWh differential. At California PG&E rate, the EV rate at night is about $0.10/kWh and $0.42kWh for on peak which is a difference of $0.32. That would pay for the cost. However, 7kWh is NOT enough to pay for the rest of the household usage. The E-6 plan is not sufficient to pay for the difference. So, unless there is a huge favorable TOU difference AND you can benefit ALREADY with low peak TOU usage, then… Read more »

If PGE&E offered this, I’d definitely look into it very carefully. We’ve got solar and the EV electric rate so it probably wouldn’t make sense from the perspective of lowering the electric bill. But if it can shave peak demand and provide backup power in case the grid goes down, I’d be interested. We only have 100 amp service, the power lines are underground, and I was given a rough estimate of $17,000 to upgrade to 200 amp service. I also have two gasoline generators we used for our burning man camp, but they are so loud and our neighborhood is normally so quiet that I’d be reluctant to use the gas generators unless the situation was pretty dire.


The quietness of the system is a benefit for sure.

I doubt PG&E would offer it, especially at this kind of rate.

The generators you have are louder because they are cheap portable kind. The standby/fixed installed version a bit quieter. But portable version has a benefit since they are portable.

Now, assume you still live in PG&E zone, how often do you lose power to make the 7kWh system worth the cost is another question. But since you own a Tesla, I guess “cool factors” alone is enough for you to justify the cost.


A prolonged power outage would be a low frequency / high impact sort of event. I’d love some sort of battery storage system and associated equipment that would allow us to use the solar system to go off grid for an extended period of time if we needed to and gave us the benefits of higher amperage service for less than $17,000. Whether or not the equipment has a Tesla logo on it is less important.


Yes, backing up the solar system is definitely a plus. But you can’t depend on that for your power backup. Often the weather related outages also mean your solar aren’t generating much power either.

$17K is a big budget, you can install a fixed generator system for about 1/3 of that cost which would be about 2x to 3x more powerful. But it won’t be nearly as elegant as battery system.

If you only care about backup, then the 10kWh system would be better. $17K should be able to buy 3x the system for almost 20kWh. But you would never pay back in terms of investment.


Your analysis is based entirely on saving money on your electric bill. Many people in the northeast – especially upstate NY and northern New England (VT, NH, ME) – buy backup generators for their homes. You really should compare the utility / expense of a power wall versus a standby generator. Many of which constantly consume electricity / gas even while standing by. Many more simply don’t work when they are needed from 9 months of neglect. I’m guessing the powerwall will be pretty reliable over its 10 year lifespan.


“– buy backup generators for their homes. You really should compare the utility / expense of a power wall versus a standby generator. ”

They don’t compare since the 7kWh system is only capable of 3kW peak or 2kW sustained rate. That is a pretty cheap generator…

Those larger ones you are talking about would be equivalent to several 7kWh system…


Granted 7kWh / 3kW peak is equivalent to a rather small generator. You can buy one that size which is small enough to carry around by hand. But I personally know a few people who have bought them for backup. This doesn’t back up your whole house, but it allows you to keep food in your fridge from spoiling. (They say that more than 4 hours without power will cause food to spoil in your fridge).

Here is a fairly comparable generator (at least in terms of power output):–carb-/hndn658140,default,pd.html?ref=pla&zmam=31282435&zmas=47&zmac=722&zmap=hndn658140&gclid=CJXsqJuw0ckCFUgXHwod96wEQQ

It’s listed for almost $2k. Sure, you can get cheaper ones, but they won’t be as reliable. Even this one though requires some maintenance. It’s not guaranteed to fire up if you haven’t touched it in 2 years. Moreover, this generator is not integrated into your house like the PowerWall. If you lose power, you have to 1) be around to notice, 2) drag out the generator and hook it up, 3) Hope it fires up… the PowerWall does all that for you.


“This doesn’t back up your whole house, but it allows you to keep food in your fridge from spoiling. ”

that is about what a 7kWh/2kW (3kW peak) powerwall can do as well.

If you want a better system, then you can installed a fixed 7kW generator that connects to gas line, propane or diesel for less than $2K each. Those system are far powerful and more reliable. You only need to occasionally start them to keep the “lube” going.

“Moreover, this generator is not integrated into your house like the PowerWall. If you lose power, you have to 1) be around to notice, 2) drag out the generator and hook it up, 3) Hope it fires up… the PowerWall does all that for you.”

Features comes with cost. As I stated above, you can install a fixed generator system with bypass switch and breakers for about $3K that is almost 2x to 3x the power.

Not to mention that that Powerwall only has 7kWh for $6500 where your generator is potentially much higher than that for CNG/Propane type and only a few gallons of fuel for the diesel or gasoline version.



“…the 7kWh system is only capable of 3kW peak or 2kW sustained rate. That is a pretty cheap generator…”

From the very first announcement of the Tesla PowerWall, it has appeared to me that Tesla never intended for a single unit to supply sufficient power for a typical American household. They say that European households use only about half the power of American houses. Here’s the rule of thumb I suggest:

Small cabin or efficiency apartment: 1 PowerWall

Typical European single-family dwelling: 2 PowerWalls

Typical American single-family dwelling: 3 PowerWalls

The PowerWalls are engineered to be fit together side-by-side, as shown in the picture above. So it seems that Tesla intended from the start that there be multiple units used in a typical installation.


GMP is offering this in the US with $6500 for a single unit.

That is a bit steep in price for the capability.


For new lead batteries are still the choice at $700 for 7kwhrs well shopped.
By the time they need replacing in 5-7 yrs lithium will have dropped to $150/kwhr retail making them worth buying.
I love Tesla but the price is too high and GMP’s price is way too high.


Specs on say 3.3 kW ‘power’, 7 kWh storage, daily cycles, 10 year warranty, with a voltage of 350-450 V, and 9.5 A.

Not sure how that integrates with a homes 240/120V panel though, and how that changes the outcome in terms of peak and sustained.

My daily usage is between 8 and 30 kWh (charging 24kW electric vw golf battery) in december, with some days not charging the car being below 3kW per hour at all times (2.94 peak), with charging, peak is closer to 8kW per hour. Washer+Dryer+Dishwasher+TV may push this above 3kW at times, but apparently that does not happen too frequently.


A typical electric clothes dryer alone consumes around 3-3.5 kW of power. I don’t think it’s realistic to assume that one single PowerWall is sufficient to power a typical American household. In fact, I doubt just one is sufficient for even the typical smaller European ones.

With just one PowerWall supplying power, you’re gonna have to keep a close eye on your home’s total power consumption at all times, and schedule for example use of an electric dryer only at night, after nearly everything else has been powered down… that is, if just one PowerWall is sufficient to power that electric dryer at all. Hopefully you have a gas dryer instead?

As I said elsewhere in this comment section, I don’t think Tesla ever intended a single PowerWall to power the typical American household. The photo above shows a twin unit installation, which is probably sufficient for a typical European household. For American households, which on average have about twice the square footage, three PowerWalls seems more practical.


Wow, great news. And very flexible options available to subscribers.


$6500 is a lot more than Tesla’s price, so would need to know the details of what’s included. If it includes inverter and installation then that is more reasonable.


I think $6500 is implied that you get the inverter and installation.

A 3kW inverter should only cost about $1500ish..

So, another $2000 for labor to install + all the bypass switch and misc parts…


I’m not a Vermonter, but I have family there. I should bring this up next time I see them. I assume GMP will also offer this in Burlington as well as the pilot program in Rutland.

This is a good step for Vermont. The state is shutting down / has shut down all of their nukes. They have been a net importer of foreign electricity for decades now – buy much of their power from Quebec. There is a big push for solar and wind, and having a distributed network of storage would be a good supplement to that. Plus Vermonters like to think of themselves as the “leading edge of green” (West coast be darned!).

Mister G

I wish Florida utilities would follow this model.

George Bower

All these big agreements with the power company I don’t like. With my solar system it is one to one. I put in 1 kwh and I can take it out again even Steven. That’s the way I want to keep it.

It is none of their business if I want my own storage.


So you want the grid to provide you a perfect lossless battery for no charge, forever? I think that is unreasonable. Net Metering is a huge benefit to those with solar panels / wind turbines / other local micro-generation. But it is unsustainable to think we can apply it to everyone everywhere in the country.

I love the idea of sharing the cost with the grid. The utility can then implement more renewables with a lot of distributed storage capacity. And you get a backup in case of power outages. The PowerWall is under warranty, so neither of you have to worry about wear-and-tear on the battery. It’s a win-win.

Now if you really want to keep the PowerWall on your side of the meter, you can. You just have to pay full price for the unit, and then it is invisible to the utility that you even have storage. Just the way you want it.

George Bower

“So you want the grid to provide you a perfect lossless battery for no charge?”

That’s what’s in my contract. So yes.

I signed the contract 7 years or so ago before the utilities figured out solar could be a threat to their business model.


Yup, we got a great deal with net metering. I just don’t expect it to last as more and more people install PV. If you signed a long-term contract, then you should be grandfathered in for its duration, with nothing to worry about.

George Bower

“Now if you really want to keep the PowerWall on your side of the meter, you can. You just have to pay full price for the unit, and then it is invisible to the utility that you even have storage. Just the way you want it.”

At first it looks expensive but on second though it might not be so bad if it includes the new inverter I would need to make it work.

Seems like last time I looked at it it was $2000+ for a new SMA central inverter.

George Bower

I think some used Leaf cells would be much more economical. Who needs liquid cooling in this pack?


This is one of the many possible end-of-life uses for my Leaf’s pack. When it degrades too much for me, I probably won’t replace the battery. I’ll probably just buy a new Leaf/Bolt/Model III. And the Leaf won’t be worth enough to be worth reselling. I suspect that the Leaf will be worth more to me in parts than I could get by selling it.

Somebody else will probably beat me to the punch and figure out how to do this. If they don’t, maybe I can put my Electrical Engineering degree to use and figure it out myself. But I suspect that a large percentage of the early adopter crowd is the engineering type, so there will be lots of tinkerers.

George Bower

Hmmmm. I wonder what it would take to put in a newer battery that isn’t supported by Nissan. I’m thinking just off the top of my head but maybe it could be done with just some software changes.


Someone will probably try their hand at doing just that. I suppose whether they share / sell that idea depends on how cost-effectively they can do it.

Personally I don’t think I would ever go this route. The first-gen Leaf has served me well so far, but there are too many things it is missing to be a long-term keeper. Plus, it’s ugly.

I suspect that I will salvage what I can from car: batteries, charger, maybe even the motor if I want to try my hand at a conversion (I’m considering either an old pickup, or possibly a small runabout boat). The rest I’ll just scrap.


I thought you were mistaken about the liquid cooling but you’re right. It must be a VERY simple implementation.


Yup. With such a slow charge/discharge rate, compared to “fast charging” an EV, or an EV battery pack powering an EV running at highway speed, there’s probably no need for for a liquid cooling system for the battery pack. I’d guess that at most it might need a small fan for forced ventilation, like a desktop computer has*. And assuming the PowerPack is installed in a heated part of the house, no need for a battery heater either.

*Of course a PowerWall is capable of putting out a lot more power than a small computer consumes, but it also has a much larger surface area than a small computer’s power pack, and therefore has a larger heat radiating surface. It may benefit from radiator fins for greater passive cooling.


I have only one thing to declare “stay away from green mountain”, they used to be a decent company, after NRG bought they are just a green washed devil. Your rates will hike with no explanation and you will pay a LOT for electric bill even if you half your consumption.


My mistake, Green Mountain Power may be good company. My previous comments were about Green Mountain Energy, which was bought by NRG.