Tesla Powerwall 2

[jflorey2]

Anyway, stranger things have happened. Some places require solar on new homes; if home batteries go mass market, some places might start mandating them, too.

And we will have a repeat of the 1970's solar-thermal debacle.

Much better to just do real time pricing for power and let people decide if they want batteries.

[Sunking]

West-facing (or tracking) systems would help reduce total energy storage needed a bit, but they make the system ramp-up at sunset even steeper.

Anyway, stranger things have happened. Some places require solar on new homes; if home batteries go mass market, some places might start mandating them, too.

Dan when are you going to learn no one here likes you and you are not welcomed here. You will be attacked every time you show up here. Go ahead and complain, it will not be heard because even the Moderators attack you.

[J.P.M.]

West-facing (or tracking) systems would help reduce total energy storage needed a bit, but they make the system ramp-up at sunset even steeper.

Anyway, stranger things have happened. Some places require solar on new homes; if home batteries go mass market, some places might start mandating them, too.

Dan: Reality is, the goal for most homeowners is a lower electric bill. Until residential level energy storage becomes much more cost effective ( == lower price) and is provided by outfits besides those run by a con man, it ain't there yet.

As for west facing systems, since they will provide more energy later in the day (but still less energy overall than will a more southerly orientation), the ramp up in demand on the grid at sunset may be steeper, but that will be due to the shorter time of ramp up, or sharper drop off of west facing panel output as f(time), not the increase in demand on the system. Let the POCO and free market/demand figure that one out. You can't do it.

A generally available, safe, viable, cost effective and small scale (e.g. residential level) storage scheme - when and if it becomes viable - and it ain't here yet - will actually deflate the argument for more westerly facing arrays being more cost effective under T.O.U. billing tariffs. (which, at least for most of CA, they are not anyway, at least not beyond about a 200 - 210 deg. azimuth +/- some).

In the limit, and theoretically, the larger a residential storage unit is, the more it will tend to take on some of the characteristics of a net metering tariff, that is and primarily, it will tend to approach an infinite storage size.

On a grid scale, depending on individual loads, any residential storage can smooth out the day to night transition from local (residential) generation to meeting demand with POCO supplied grid power. It will be one way/tool/method to move to the future. The challenge will be, as always, to watch out for the con men and their ignorant minions who, in their wishful, shortsighted, myopic and mostly self-centered non thinking, unknowingly support the con artists. Caveat Emptor.

[SunEagle]

West-facing (or tracking) systems would help reduce total energy storage needed a bit, but they make the system ramp-up at sunset even steeper.

Anyway, stranger things have happened. Some places require solar on new homes; if home batteries go mass market, some places might start mandating them, too.

Heaven forbid that politics will require people into purchasing an energy storage system even if the price comes down. Talk about a reason to push back and vote out some politicians.

[DanKegel]

Or just face arrays west. Lots cheaper.

West-facing (or tracking) systems would help reduce total energy storage needed a bit, but they make the system ramp-up at sunset even steeper.

Anyway, stranger things have happened. Some places require solar on new homes; if home batteries go mass market, some places might start mandating them, too.

[J.P.M.]

Yep. I went to a talk at this year's Solar Expo in San Diego. It was from the SEIA and it was mainly focused on the new TOU rates for SDG+E. One of the most immediate conclusions was that "south at latitude" wasn't going to be the best choice for new installations under the new rate plan, since peak times are now 4 to 9pm - so 4pm power becomes roughly twice as valuable as noon power. Batteries are the "hard" way to shift generation that late; orientation is a lot easier (at least, before installation begins.)

Well, FWIW, I've got what may be a useful tool.

Last year, after T.O.U. rates were somewhat finalized, I realized that if I separated solar production and treated a residential solar array as a revenue producer as well as an electrical generator, I could get solar revenue as f(array orientation, T.O.U. tariff rates and times). As long as the user or array user is under NEM and the array output is less than the annual usage, an array's output at any given orientation just like its electrical generation, can be considered fixed for modeling purposes as long as or until/unless rates change. And when rates (and T.O.U. times) do change, as they will, adjustment of the rates and times is a relatively easy matter. It then becomes possible to investigate the revenue generated under any orientation and then, if desired, to optimize array orientation. This works with any reasonable solar modeling program that has hourly of more frequent time steps.

Using this logic, that is, separating array revenue from household usage, it then becomes possible, or at least the user has another tool, to examine and compare the revenue production of various orientations. It's also possible using a 1 STC kW array to then estimate how big an array they may need to offset a chosen portion of any particular usage and usage pattern and/or bill. There are other uses as well.

Using Miramar TMY3 data and SDG & E's DR-SES tariff, it turns out that there is a rather broad optimum of azimuth and tilt that's around a 30 degree tilt and more broadly around a 215 to 235 degree orientation. The last time I used the spreadsheet, a 1 kW array produced (or offset) about $425 to ~ #445/yr. of a DR - SES bill.

I'll update that for the most recent rate schedule and post an edit to this post after dinner.

Later:

Using DR-SES latest rates (01/01/2018) and PVWatts with 10 % system losses for Miramar MCAS, TMY3 data, all array tilts at 20 deg. and in 25 deg. increments for azimuth:

Azimuth/Bill Offset Revenue/yr. per STC kW of array.

180 deg. = $453/yr.
202.5 deg. = $457/yr
225 deg. = $451/yr.
247.5 deg. = $439/yr.
270 deg. = $418/yr.

So, a 5 kW array at a 180 deg. az. and 20 deg. tilt in inland San Diego will produce about 5* $453 = $2,265 in annual bill offset.

How the owner of such an array chooses to use that electricity both in terms of quantity and time pattern is a separate matter and independent of array revenue - again, provided the array produces less than annual usage - Examples: With no peak summer use (and therefore @ ~~ $0.25/kWh or so rate), that array may offset ~~ 9,000 to 9,200 kWh/yr. of use. If all usage is at peak rate times in the summer (and therefore at $0.53781/kWh), that $2,265 will offset ~ 4,200 kWh. Neither scenario is likely. Point is, the (lifestyle) choices are with the user, both for as to how much is used and when to use it.

30 deg. tilts are about $5/yr. higher revenue producers than the 20 deg. tilts for the same azimuths until the azimuth gets to ~ 247 deg., were 20 and 30 deg. tilts are almost equal in annual revenue production. After that az. at 30 deg. tilts, $ revenue is higher by ~ $5/yr.

I haven't done lower or higher tilts yet, but the results at lower tilts will be less variable and lower $ production as f(azimuth), and more variable with also lower $ production as f(azimuth).

The revenue offsets for the same orientations before the T.O.U. peak and other times were adjusted were generally about 22 -25 % higher than the above figures. That's the basis of my claim that after T.O.U. peak times were shifted to later in the day and other adjustments made, residential PV in San Diego, and as it would seem similarly in the other CA investor owned utilities territories, got either 20+% less cost effective or PV ROI decreased by 20+% , or, PV payback times got 20+ % longer.

[jflorey2]

I'd bet somewhere between S and W might be better for both users and POCOs than a 270 deg. or close to it azimuth. A good part of the time after noon and before late afternoon, and depending on location, tilt and a couple other things an az. closer to 225 deg. might be closer to a good combination of bill offset and lowering the duck curve, but there are too many variables related to site and time of year to make better estimates other than maybe my educated SWAG that given choices, south is better than west and somewhere the two is where the optimum bill offset will be found for most CA applications and locations. It's not usually an either/or choice or solution.

Yep. I went to a talk at this year's Solar Expo in San Diego. It was from the SEIA and it was mainly focused on the new TOU rates for SDG+E. One of the most immediate conclusions was that "south at latitude" wasn't going to be the best choice for new installations under the new rate plan, since peak times are now 4 to 9pm - so 4pm power becomes roughly twice as valuable as noon power. Batteries are the "hard" way to shift generation that late; orientation is a lot easier (at least, before installation begins.)

[Mike90250]

And then something like this pesky storm comes along, cloudy for 3-4 days, Batteries aren't going to like that.

CloudsRain_4-2018.gif

[J.P.M.]

Or just face arrays west. Lots cheaper.

I'd bet somewhere between S and W might be better for both users and POCOs than a 270 deg. or close to it azimuth. A good part of the time after noon and before late afternoon, and depending on location, tilt and a couple other things an az. closer to 225 deg. might be closer to a good combination of bill offset and lowering the duck curve, but there are too many variables related to site and time of year to make better estimates other than maybe my educated SWAG that given choices, south is better than west and somewhere the two is where the optimum bill offset will be found for most CA applications and locations. It's not usually an either/or choice or solution.

[jflorey2]

In California, that steep ramp-up lasts for three hours ( see caiso.com/documents/flexibleresourceshelprenewables_fastfacts.pdf ) and raises demand by 10GW.
That's in a state with 12 million housing unilts (half of them single family).
If each housing unit in the area served by a utility had 4kWh of storage, that would handle the surge.

Or just face arrays west. Lots cheaper.

[J.P.M.]

In areas with lots of solar, there's a huge ramp-up of demand on the nonsolar power generators towards sundown, and in the past, that's the kind of demand that was met by peaker plants.

In California, that steep ramp-up lasts for three hours ( see caiso.com/documents/flexibleresourceshelprenewables_fastfacts.pdf ) and raises demand by 10GW.
That's in a state with 12 million housing unilts (half of them single family).
If each housing unit in the area served by a utility had 4kWh of storage, that would handle the surge.
So 4kWh of storage can be significant, and it's not unreasonable to suspect utilities and/or communities will start eyeing storage as a way to solve certain problems as prices come down.

And if every U.S. driver used an average of 1 gal of fuel less per day, Elon Musk would be able to use the crude oil offset savings to land more rockets in the desert for less money and more often.

So friggin' what ?!?! If my aunt had balls she'd have been my uncle. How does your "what if" nonsense matter to anything constructive or productive. ? Why don't you go write fairy tales ?

Dan: You're still wasting your and everyone else's time who doesn't know your M.O.

Your latest is yet another example of your nonsense that does nothing constructive, is relevant to nothing, and the type of tripe that can and probably often does send people as ignorant as you are about R.E. and other energy matters off on wild goose chases.

You are not helping things with your antics. Your actions, whether you know it, or believe, or not are hurting the cause of renewable energy by spreading this junk around and in so doing trivializing what some of us have spent a lot of time trying to build up. Your actions only give the R.E. naysayers examples of the type that are near impossible to defend. Seen your type of actions for 40+ years.

More of your self ego stuffing, rose colored glasses useless junk. You've produced another useless, irrelevant piece of trash and another example of your stuff that I find mostly useless usually an irrelevant and simply stupid insult to my intelligence.

[SunEagle]

In areas with lots of solar, there's a huge ramp-up of demand on the nonsolar power generators towards sundown, and in the past, that's the kind of demand that was met by peaker plants.

In California, that steep ramp-up lasts for three hours ( see caiso.com/documents/flexibleresourceshelprenewables_fastfacts.pdf ) and raises demand by 10GW.
That's in a state with 12 million housing unilts (half of them single family).
If each housing unit in the area served by a utility had 4kWh of storage, that would handle the surge.
So 4kWh of storage can be significant, and it's not unreasonable to suspect utilities and/or communities will start eyeing storage as a way to solve certain problems as prices come down.

Dan stop using the big numbers to defend the use of home storage. I would say less than 5% of those 12 million houses could afford a 4kWh storage system let along a way of charging it from solar.

Prices have to come down to a "commodity level" for most people to even think about spending it on energy storage.

[Sunking]

? I pointed to Maui as one of the few places it might make economic sense. I agree with J.P.M. and others that even 11 cents / kWh for storage is not economical in most areas. I guess given the tensions here I should have made that explicit.

Do you agree that, if the Powerwall could make sense anywhere, it'd make sense first in areas where power's really expensive, and there's no net metering? If so, we're on the same page.

Good grief, have you not been banned yet? Give up.

[DanKegel]

In areas with lots of solar, there's a huge ramp-up of demand on the nonsolar power generators towards sundown, and in the past, that's the kind of demand that was met by peaker plants.

In California, that steep ramp-up lasts for three hours ( see caiso.com/documents/flexibleresourceshelprenewables_fastfacts.pdf ) and raises demand by 10GW.
That's in a state with 12 million housing unilts (half of them single family).
If each housing unit in the area served by a utility had 4kWh of storage, that would handle the surge.
So 4kWh of storage can be significant, and it's not unreasonable to suspect utilities and/or communities will start eyeing storage as a way to solve certain problems as prices come down.

[Charlie W]

Along those lines, it's interesting that electric meter maker Itron and storage vendor Sonnen announced a partnership recently. Some towns already require solar on new houses; requiring 4kwh of storage as well, and using it to reduce peak system load to avoid adding peakers, may well be in the cards someday.

I'd have to think it over at some point, but my initial reaction to 4 kWh of storage is a big "so what." In winter, my house uses 4 kW per hour. If storage were to matter here, I'm thinking I'd need a hell of a lot more capacity than that. And where I live, peak smoothing is irrelevant anyway. My county is thinly populated and gets 89% of its power from hydro and wind; another 8% from nukes; and 3% from coal. Even on the hottest summer days, there just isn't enough of a peak around here to move the needle.