GMP and Tesla Batteries

Lease one for $15 per month.

The Tesla Power 2 home battery system can fit inside or outside. Its dimensions are a height of 1.3m, width of 0.86m, and a thickness of 0.18m. Photo credit mcelectrical.com.au

By George Harvey

Green Mountain Power (GMP) is making an extraordinary offer to its customers. They can lease a Tesla Powerwall 2 battery at the unheard of price of $15 per month. An alternative to the monthly fee is a single payment of $1,500. Since the usual price to buy the battery is $5,000 plus installation, renting is an amazing deal. The lease is good for ten years, so the total payment will be $1,800, only a fraction of the purchase price.

The Tesla Powerwall 2 is advertised as providing 13.5 killowatt hours (kWh) of useable battery storage. According to GMP, this provides eight to twelve hours of battery backup for an ordinary household, operating at usual use levels. It can produce five kWh continuously but will produce as much as seven for a short time. The Tesla Powerwall 2 is rated for indoor or outdoor installation, though its operating range is -4° F to 122° F, so in Vermont it may be best to install it indoors.

There are two advantages for the customer who leases the battery. One is an ability to buy power at a low price during times when demand is low, and then use it later at a time when demand is higher. Since demand alternates between high and low cost periods daily, this may be sufficient to reduce electric bills significantly, a pretty good deal for $15 per month.

The other advantage for the customer is that the battery will provide power during grid outages. These tend to be short in Vermont, averaging only two hours, but the battery will provide much more than that. We would advise anyone with a battery to try to find out how long any outage they may experience is expected to last, so they can ration their load appropriately, if that would be necessary.

The Tesla Powerwall 2 batteries can be set up to use on-site solar panels, in which case they offer the customer the additional advantage of having a certain amount of power even during very long grid outages. Solar power is not a necessary part of the system, but one way or the other, a grid connection is needed. This is so GMP can also use the batteries; without that ability, they have no economic reason to make such an offer.

Under the terms of the lease, GMP is allowed to draw from the battery during high demand times. This does not change the rate-payers bill directly, but indirectly it helps all of us. Having 2,000 Powerwall 2 batteries available will be the equivalent of taking 7,000 households off the grid during high demand times, and this can change the wholesale price of power significantly. Prices for wholesale power can spike to 60¢/kWh or higher in Vermont, but GMP has to sell it at the standard rate regardless of what they are paying, at times losing substantial amounts of money. Being able to reduce the peak demand prices for power creates a much more stable market, in which GMP can take fewer risks and spend less money on power while customers pay lower prices.

The Powerwall 2 batteries are expected to last for ten years, during which time they are under warranty. At the end of their lifetime, Tesla will take them back to recycle the materials in them. Green Mountain Power spokeswoman Kristin Carlson told us, however, that if they are still functioning well, there is no requirement that they be recycled at the end of the lease. In that case, the customer can still use them without paying the $15 per month rent until they are no longer useful. There is no option to buy at the end of the lease, because there is no advantage to the customer to do so.

Customer interest in the program is very high, and it is altogether possible that the batteries will all be spoken for when Green Energy Times goes to press. Customers are advised to sign up for the batteries anyway, because there will almost certainly be some who decide to opt out, and the batteries will go to whoever is next in line, on a first-come first-served basis.

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