patrick.net

EBGuy says

You obviously didn't follow the links.
Under SGIP, the first 10 kWh receive a $400/kWh incentive, and the remaining 3.2 kWh are eligible for a $200/kWh incentive, worth a total of $4,640. That’s enough to cover almost the entire cost of purchasing the Powerwall equipment, which is priced at $5,500.
Incentives have fallen to $350/kWh, but are still quite generous when combined with the federal rebates. Plus you'll be the only guy with electricity on your block after the Big One hits.

True, I did not. I did check it out and you missed the total cost. It doesn't make financial sense.

Component
Estimated Cost
Powerwall battery $5,500
Installation cost $2,000 to $4,000
Shipping, components and fees $3,000 to $4,000
SGIP value -$4,640
ITC value -$3,150 to -$4,050
Total cost (approximate) $2,710 to $4,810

I was originally just going by what they had told me at a Tesla store.

Strategist says

Yet.
The day will come when energy storage will be dirt cheap. At that point even utilities will be doomed. Imagine one day taking your 1000 KW powerwall the size of a laptop to Walmart for a quick charge.

This is the key point. Yes, I do agree that one day soon, completely off-grid will be cost effective, even dirt cheap, but also consider that the grid could become dirt cheap as well. Consider places where already a surplus of electricity makes the price go negative. I believe grid tied will become a $10 a month charge for as much as you want.

I just don't lose sleep over the potential for a power outage. In San Diego it happens once a decade. I even own a 100 amp hr battery for a small inflatable boat I have. I even have a small inverter. Another thing to consider is how electric cars can be used as electricity buckets. My Bolt has a 60KWH battery. I'd rather invest in a nice 3KW pure sine wave inverter and that would more than take care of a power outage. If nothing else, I can connect to the Internet from my iPhone, it even has a flashlight. Power outages just don't worry me.

Malcolm says

Strategist says

Yet.
The day will come when energy storage will be dirt cheap. At that point even utilities will be doomed. Imagine one day taking your 1000 KW powerwall the size of a laptop to Walmart for a quick charge.

This is the key point. Yes, I do agree that one day soon, completely off-grid will be cost effective, even dirt cheap, but also consider that the grid could become dirt cheap as well. Consider places where already a surplus of electricity makes the price go negative. I believe grid tied will become a $10 a month charge for as much as you want.

The grid costs a lot in overheads, maintenance of the power lines, billing etc. Even if the wholesale cost of electricity was to go to zero, these costs would still remain and go even higher, because wages etc keep going higher.
We are a long way from utilities being outdated, but when it happens, it happens suddenly. Look how quickly Kodak, an American icon collapsed when digital cameras arrived. Even oil companies will be obsolete because there is no way they can compete with roof top solar power at 9 cents/kwh, which equates to 3 cents per mile to drive an electric car. Elon Musk will go down in history as the entrepreneur who single handedly destroyed the multi trillion dollar oil industry.
Those who drive electric cars like you, see the astonishing value. I'm surprised at the stiff opposition to electric cars and renewable energy by Church goers. Fucking stupid.

Strategist says

The grid costs a lot in overheads, maintenance of the power lines, billing etc. Even if the wholesale cost of electricity was to go to zero, these costs would still remain and go even higher, because wages etc keep going higher.
We are a long way from utilities being outdated, but when it happens, it happens suddenly. Look how quickly Kodak, an American icon collapsed when digital cameras arrived. Even oil companies will be obsolete because there is no way they can compete with roof top solar power at 9 cents/kwh, which equates to 3 cents per mile to drive an electric car. Elon Musk will go down in history as the entrepreneur who single handedly destroyed the multi trillion dollar oil industry.
Those who drive electric cars like you, see the astonishing value. I'm surprised at the stiff opposition to electric cars and renewable energy by Church goers. Fucking stupid.

You can see the costs on your electric bill. The cost of transmission and distribution should be a separate line item. So, in theory, without generation costs, that is what it would cost you if you were subscribing to the utility. Yes, your scenario is an absolutely valid possible outcome. Another possible outcome is a completely new technology, or an excellent incremental improvement (like electric cars going from 30-60KWhrs with no increase in price). In five more years Powerwalls might be twice as valuable making it a real competitor to utilities, who in turn will reduce waste in their cost structure and get down to that $10 a month price point because they would be freely competing to get you to use them instead of trying to be self sufficient. I think most people will feel tethered to utilities for some time.

Malcolm says

Total cost (approximate) $2,710 to $4,810

Malcolm, thanks for the maths!
So $3k might not be too bad for battery backup piece of mind, plus you can your program your Powerwall to supply electricity during peak rates.
Using PG&E EV rate schedule A, peak rate is $.21 /kWhr higher during summer (6 months) and $.12/kWhr higher the rest of the year
Discharge battery during Peak rates (~5 kWhrs to maintain SOC) .
$.22 x 5kWhr x 182 days = $200.20
$.12 x 5kWhr x 183 days = $109.8
--------------------------------------------
Savings per year = $310
Payback in 10 years (battery warranty is for 10 years as well).

EBGuy says

Malcolm, thanks for the maths!
So $3k might not be too bad for battery backup piece of mind, plus you can your program your Powerwall to supply electricity during peak rates.
Using PG&E EV rate schedule A, peak rate is $.21 /kWhr higher during summer (6 months) and $.12/kWhr higher the rest of the year
Discharge battery during Peak rates (~5 kWhrs to maintain SOC) .
$.22 x 5kWhr x 182 days = $200.20
$.12 x 5kWhr x 183 days = $109.8
--------------------------------------------
Savings per year = $310
Payback in 10 years (battery warranty is for 10 years as well).

When I was reflecting on it, I was thinking there might be a value proposition for peak shaving. I'm still wondering if you would still use a PV system and how that plays in since it is producing at a lower tier rate. 10 years is still a little long for me, but if they get it to 5 years, I would say that it makes sense by itself without a PV solar system. If daytime rates fall low enough, a PowerWall will make more sense than a PV system. Interesting dilemma.