Some truth to people who think we can be 100% renewable

[Lakewood90712]

Panel orientation

So on the tech 057 residence, 84 panels are in the photo. Unknown if all are the same watt. Salt Box style of roofs are a long way from ideal, especially this one with east / west .

Move 10% of the panels to the east, on the front of the house ( ugly ) , move half of the existing panels on the west facing roof to the ground, facing south.
substantial solar capture without more infrastructure. Some diversity in panel orientation can actually increase capture depending on the time of year.

Or just rotate the house 90 degrees . The HOA ,if he has one, would be just thrilled with collectors facing the street. This tech 057 guy is not an idiot so I am sure he has looked at several options.

 

[NW-Bound]

Come to think of it, his west-facing panels on the roof are really suboptimal for the winter. In the summer, they are not bad as they look. As mentioned in an earlier post, NREL data shows that he should be getting more than 220kWh/day in the peak month of May, and he was getting close to that many days. In fact, I saw that on August 24th, 2018, he got 232kWh. Very impressive!

Thinking some more about this, even in the winter, he might be close to being able to be completely off-grid, except for winter storms. One must be willing to curtail consumption during bad production days, and because he has the grid to fall back on, he does not seem to care that much about conservation.

I think that if one wants 100% self-sufficiency, one must be able to cut back usage on bad days, and also has a lot of reserve capacity.

Kind of like the 4% WR in retirement. You must be prepared to go broke in 30 years, and get used to see your stash going down and down if you run into a bad sequence of returns. Else, use 2% WR, and be willing to die leaving a lot of money behind.

 

[NW-Bound]

So on the tech 057 residence, 84 panels are in the photo. Unknown if all are the same watt...

His specs say 102 SunPower panels, of 435W each.

These are among the best commercially available PV panels that you can buy, and with efficiency of 20%.

 

[Lakewood90712]

If he does have the rest of the panels on the front (east facing) , then he would seem to have the best config. possible for the existing site.

What he needs to do is buy 2 more Tesla's and use the battery in each connected to backfeed to his system on extended cloudy/ cold weather. Using the battery on a parked electric cars has been discussed as a legitimate strategy to cope with grid outages and peak demand. In this case the 'Grid" is his residence and garage wiring.

 

[NW-Bound]

If he does have the rest of the panels on the front (east facing) , then he would seem to have the best config. possible for the existing site.

What he needs to do is buy 2 more Tesla's and use the battery in each connected to backfeed to his system on extended cloudy/ cold weather. Using the battery on a parked electric cars has been discussed as a legitimate strategy to cope with grid outages and peak demand. In this case the 'Grid" is his residence and garage wiring.

Why? Facing south is best, but it's a tie between facing east or west. One has peak production before noon, while the other does in the afternoon. The total power production is the same.

Perhaps you were suggesting that the east-facing panels would provide more power earlier in the morning to help out sooner after a night of battery depletion.

About drawing power back out of a Tesla, I don't know if there is a way to do that without breaking into the battery pack, and compromising its integrity. One then needs custom-made inverters to convert the high DC voltage of 375V to household AC voltage.

I wonder if any EV manufacturer has talked about allowing this, and making provision for it.

 

[Lakewood90712]

Why? Facing south is best, but it's a tie between facing east or west. One has peak production before noon, while the other does in the afternoon. The total power production is the same.

Perhaps you were suggesting that the east-facing panels would provide more power earlier in the morning to help out sooner after a night of battery depletion.

About drawing power back out of a Tesla, I don't know if there is a way to do that without breaking into the battery pack, and compromising its integrity. One then needs custom-made inverters to convert the high DC voltage of 375V to household AC voltage.

I wonder if any EV manufacturer has talked about allowing this, and making provision for it.

With that east/west saltbox style roof, splitting part between west ( second best ) and east ( 3rd best) is wasteful, but no other choice.

The EV and utility engineers have dreamed about using the EV car battery as a utility controlled grid buffer for a long time. I would bet Tesla has done some test vehicle experiments with this.

Would require major hacks of the vehicle hardware and software. This owner seems to embrace technical challenges.

 

[TwoByFour]

The EV and utility engineers have dreamed about using the EV car battery as a utility controlled grid buffer for a long time. I would bet Tesla has done some test vehicle experiments with this.

EV batteries are not optimal for PV storage. When Musk first proposed the PowerWall, he was shooting from the hip and assumed the batteries used for Tesla would work fine in a PowerWall. Turns out they don't work all that well and because of that his giga-factory had to be retooled to produce two different kinds of batteries. The main problem is the charge/discharge cycle is very different between the two uses and the EV battery burns out quicker.

Of course the other problem is that while the sun is out, the car is not at home anyway, so is not plugged into the PV system.

 

[eroscott]

How does the above compare to people living in other states? Just looked it up, and found that the average Midwest household uses 766.4 gal of heating oil each year. That's equivalent to 31,200 kWh. That's double my electricity usage. And that is just for heating oil, as they also use electricity, and perhaps gas too. Yikes! And the average Midwest home is probably smaller than 2,800 sq.ft.

31,200 kWh average! --- I thought I was bad with an average of the past couple years 21,763 kWh --- but then again we have 3 electric cars charging after midnight when my rates (hourly plan) are cheaper. Those numbers are from a TED power monitor and don't include our gas heat nor cooktop tho. House is 3500 sq.ft. (downsize in 5-7 yrs).

...
Thinking some more about this, even in the winter, he might be close to being able to be completely off-grid, except for winter storms. One must be willing to curtail consumption during bad production days, and because he has the grid to fall back on, he does not seem to care that much about conservation.

I think that if one wants 100% self-sufficiency, one must be able to cut back usage on bad days, and also has a lot of reserve capacity....

wk057 · Dec 8, 2018

Sucked up a bit of coal power to top off my home batteries in prep for the coming winter storm. First time I've ever used the inverters for charging outside of just testing.

Another view of his system and BMS management in this youtube. Description is interesting too.

Published on Nov 1, 2018

So, I've been working on getting my custom BMS project completed. I've been collecting data from it for a while and finally took the time to visualize some of it. It's super cool to see the thing in action. Some of its balancing decisions are immediately obvious, others not so much, but the algorithm is working perfectly and keeping the entire array of *216 cell groups* in virtually perfect balance.

This is in spite of the fact that first, the modules are not all matched and are from at least four different Tesla vehicles with varying mileage/use. Also, I had to swap out module 3B with my cold spare (sitting on a shelf since 2015) due to a failed BMS experiment destroying a cell group over the summer. You'll see in the video that this module isn't well matched with the one next to it (3A), but the custom BMS does a great job holding them in line with a max ΔmV of around 22mV in worst case situations.

This is all completely custom software running on both custom hardware and modified Tesla hardware (BMBs). The algorithms track usage and monitor how much a cell group is going to need as far as balancing goes and can actively maintain the entire pack through the full voltage range of the modules. So, not just top or bottom balancing. Takes into account module temperature to estimate internal resistance changes as well, for example. It's super complex, but works extremely well even with highly unmatched modules.

I found it fun to watch. You can also match up the timestamps with the graph of the day on wk057.solar in this image: https://wk057.solar/netusagegraphs/20... ... I plan on exposing live BMS data on wk057.solar soon.

Same system will be in use in the 3000EV.

Some details:
* The system has 216 cell groups (15,984 cells total).
* Nominal system voltage is 44V.
* The balancing circuits are bleeders at ~39 ohms.
* Video is roughly sunrise to sunset packed into 90 seconds
* The system uses the original Tesla BMBs (battery module boards) that are on every Tesla Model S/X battery normally. The stock firmware was quite limited in functionality, so I wrote my own overhaul that adds redundancy and a lot of other tweaks.
* This has been the main test bed for my upcoming production version.
* The representation is the same as if you were looking at the front of my physical battery rack (can easily see things like warmer modules near the ceiling, coolest near the floor). I have no liquid cooling to equalize temps, currently.

Things in the video: <snip>

 

[eroscott]

Link: Tesla’s new Megapack to debut at giant energy storage project in California -- Dec 15, 2018

Electrek has learned some exclusive information about Tesla’s Megapack, the company’s upcoming new stationary energy storage product.

The big new battery system is going to debut at Tesla’s giant 1.2 GWh energy storage project with PG&E in California.

Tesla Megapack
...
Electrek can now confirm that it’s a large container-size energy storage system that Tesla plans to debut in its upcoming project commissioned by PG&E at the Moss Landing substation.

We obtained Tesla’s proposal for the project and it shows that the company plans to use ‘Megapack’ instead of its usual Powerpack for large utility-scale projects.

According to the document, a Tesla Megapack consists of long 23′-5″ (7.14m) x 5′-3″ (1.60m) battery system, which the company mostly installs back to back with another unit.
...
The California Public Utilities Commission approved the project last month and along with 3 other energy storage system,
the new energy storage capacity is so important that it will replace three gas power plants.

According to Tesla’s plan, they will deploy 449 Megapacks at the site:
...
Tesla is listing the project as having a total capacity of 1,200 MWh, which would mean that each Megapack has a capacity of 2,673 kWh.

That’s more than 12 times the capacity of Powerpack 2 in a package that could potentially fit about 8 Powerpacks.

The total capacity of those 449 Megapacks represents more energy capacity than Tesla Energy deployed throughout its first 3 years of operation – all Powerpacks and Powerwalls combined. ...

 

[ERD50]

Link: Tesla’s new Megapack to debut at giant energy storage project in California -- Dec 15, 2018

That's certainly interesting, and shows that battery tech is making inroads, but...

"the new energy storage capacity is so important that it will replace three gas power plants."

Hmmm, while that is literally true, it could be stated a different way. That could read:

"Existing gas power plants will need to burn about 10% more fossil fuel than the peaker gas plants they replace, due to round trip losses in battery storage".

Now, I understand that this may be laying a path for storage of RE excesses in the future, but we really should be calling a spade a spade.

-ERD50

 

[Lakewood90712]

That's certainly interesting, and shows that battery tech is making inroads, but...

"the new energy storage capacity is so important that it will replace three gas power plants."

Hmmm, while that is literally true, it could be stated a different way. That could read:

"Existing gas power plants will need to burn about 10% more fossil fuel than the peaker gas plants they replace, due to round trip losses in battery storage".

Now, I understand that this may be laying a path for storage of RE excesses in the future, but we really should be calling a spade a spade.

-ERD50

If my sources at CALISO are correct , the plan is excess solar and wind during the winter days would be routed to battery storage rather than PAYING ARIZONA TO TAKE EXCESS POWER , YES, I SAID PAYING TO TAKE EXCESS POWER FROM THE CA GRID as the ca state grid operator is still doing. We have a terrible problem with imbalances during sunny , windy cool weather in CA. The grid must keep base load plants connected and cannot shut off solar from small producers.

CALISO , the CA Energy Commission and the CA PUC all share fault for the situation IMO.

If heavy industry had not been driven out of CA , the market for every KW of solar energy would have immediate use.

Ratepayer money being squandered as per usual.

Today's rant from a 3rd generation Californian over, for today.

 

[NW-Bound]

Good thing AZ voters just rejected a proposition to amend the AZ Constitution to require 50% RE by 2030. The state already planned to have 15% RE by 2025.

So, we still have room to take some solar power off CA's hand when you need us to.

PS. CA could have used excess solar power when available to run a water reverse-osmosis plant to alleviate the drought.

 

[explanade]

You mean desalination?

 

[NW-Bound]

Yes. Desalination is reverse-osmosis on a large scale, and under high water pressure up to 1000 psi for seawater.

 

[eroscott]

Originally Posted by ERD50 View Post
That's certainly interesting, and shows that battery tech is making inroads, but...
"the new energy storage capacity is so important that it will replace three gas power plants."
Hmmm, while that is literally true, it could be stated a different way. That could read:
"Existing gas power plants will need to burn about 10% more fossil fuel than the peaker gas plants they replace, due to round trip losses in battery storage".
Now, I understand that this may be laying a path for storage of RE excesses in the future, but we really should be calling a spade a spade. -ERD50

Assuming ~10% comment is accurate ... ~270% [ (3*~100%)-(3*~10%)] less fossil fuel is bad? (couldn't quote ERD50 directly since he's on my ignore list but saw his comment when others quoted him.)

Reddit discussion: https://www.reddit.com/r/teslamotors/comments/a6etx9/tesla_to_build_1200_mwh_battery_station_out_of/

 

[Lakewood90712]

EV batteries are not optimal for PV storage. When Musk first proposed the PowerWall, he was shooting from the hip and assumed the batteries used for Tesla would work fine in a PowerWall. Turns out they don't work all that well and because of that his giga-factory had to be retooled to produce two different kinds of batteries. The main problem is the charge/discharge cycle is very different between the two uses and the EV battery burns out quicker.

Of course the other problem is that while the sun is out, the car is not at home anyway, so is not plugged into the PV system.

I was being facetious about buying extra Tesla's as storage.

I know Lithium EV batteries are far from optimal for stationary elec. storage.

Both Tesla and Nissan were touting re cycling used ev cells that are too degraded for ev use in stationary power storage. Nissan is doing it via solar collector and used leaf battery cell ( one cell) on remote street lamp poles. No idea of what Tesla does with individual degraded cells modules.

Tesla EV batteries are in the used market via salvage car auctions. Tesla's are auctioned off by insurance companies with very minor damage due to the astronomical body repair costs. I assume that is where tech 057 obtained his.

Newly mfg. lithium cells are not the first choice for stationary storage. Tesla powerwall has the best packaging/integration IMO, but is quite $ for the energy stored. The 10% quoted round trip energy loss for storage is optimistic.

 

[ERD50]

Assuming ~10% comment is accurate ... ~270% [ (3*~100%)-(3*~10%)] less fossil fuel is bad? (couldn't quote ERD50 directly since he's on my ignore list but saw his comment when others quoted him.)

Reddit discussion: https://www.reddit.com/r/teslamotors/comments/a6etx9/tesla_to_build_1200_mwh_battery_station_out_of/

Not sure what the point is if I'm on your ignore list, but for others -

These batteries are for storage, they need to be filled. Unless they are being filled from RE excess (I didn't see any reference to that in the article), then they are being filled from other gas plants (or maybe even coal).

So they are replacing the 3 peaker gas plants, but not the gas/fossil fuel to fill them. Might make good sense economically, but it does not change the fossil fuel equation, other than add to it because of the storage losses.

You would need to point out what is relevant in that reddit link.

What does "(3*~100%)-(3*~10%)" represent? 3 what? 100% of what? 10% of what?

-ERD50

 

[ncbill]

Not sure what the point is if I'm on your ignore list, but for others -

These batteries are for storage, they need to be filled. Unless they are being filled from RE excess (I didn't see any reference to that in the article), then they are being filled from other gas plants (or maybe even coal).

So they are replacing the 3 peaker gas plants, but not the gas/fossil fuel to fill them. Might make good sense economically, but it does not change the fossil fuel equation, other than add to it because of the storage losses.

You would need to point out what is relevant in that reddit link.

What does "(3*~100%)-(3*~10%)" represent? 3 what? 100% of what? 10% of what?

-ERD50

Losses don't matter given the economics...batteries like this would be charged off-peak, their power used on-peak.

Cheaper to build the batteries than the power plants needed to meet increasing peak demand.

 

[ERD50]

Quote:
Originally Posted by ERD50 Hmmm, while that is literally true, it could be stated a different way. That could read:

"Existing gas power plants will need to burn about 10% more fossil fuel than the peaker gas plants they replace, due to round trip losses in battery storage".

Now, I understand that this may be laying a path for storage of RE excesses in the future, but we really should be calling a spade a spade.

-ERD50

If my sources at CALISO are correct , the plan is excess solar and wind during the winter days would be routed to battery storage rather than PAYING ARIZONA TO TAKE EXCESS POWER , YES, I SAID PAYING TO TAKE EXCESS POWER FROM THE CA GRID as the ca state grid operator is still doing. We have a terrible problem with imbalances during sunny , windy cool weather in CA. The grid must keep base load plants connected and cannot shut off solar from small producers.

CALISO , the CA Energy Commission and the CA PUC all share fault for the situation IMO.

If heavy industry had not been driven out of CA , the market for every KW of solar energy would have immediate use.

Ratepayer money being squandered as per usual.

Today's rant from a 3rd generation Californian over, for today.

I'd like to see some numbers on that excess solar and wind from someone. It seems rare enough that it makes the news when it happens, so I think my view is mostly true - it's going to be mostly fossil fuel filling those batteries.

And I think there are plans for better distribution to Arizona. I think it's the subsidies that drive paying to get rid of it. Like, if they get $.01/kWh in subsidies, and have an excess, they can pay $.005/kWh to have it taken off their hands, and they make something, versus nothing.

But, as far as I've been able to figure, the excesses are far and few between, and will be for some time. When that is the case, then sure, we can talk about how this storage is saving fossil fuel and pollution, etc - but not until then.

-ERD50

 

[ERD50]

Losses don't matter given the economics...batteries like this would be charged off-peak, their power used on-peak.

Cheaper to build the batteries than the power plants needed to meet increasing peak demand.

Well, losses still matter. Of course, if the economics are greater than the losses, it works (financially).

And that's what I understand, the batteries are now cheaper than new peaker plants. But, the peaker plants produce energy, the batteries store it. So unless we have an excess of RE, we are still using fossil fuel to fill those batteries, plus enough to cover the losses.

-ERD50

 

[NW-Bound]

If you read the academic studies that were proposed earlier, you can see some of the significant first steps that are part of their 'solution'. Reduce energy consumption by 30%. We can do this by having people walk or bicycle rather than use personal vehicles. Or mass transit, for rare purposes. Eliminate meat and go to a vegetarian diet.

There are several next logical steps. Relocate people away from areas with a climate that requires cooling during the summer, or heating during the winter...

It's nice to live in areas that need no cooling in the summer, nor heating in the winter. The problem is that rich people stake their claim on these lots long ago.

Even less-than-perfect areas are also so crowded, I would rather stay where I am and put up more solar panels if I have to.

 

[NW-Bound]

PS. CA could have used excess solar power when available to run a water reverse-osmosis plant to alleviate the drought.

You mean desalination?

Yes. Desalination is reverse-osmosis on a large scale, and under high water pressure up to 1000 psi for seawater.

I meant to look up this subject to understand it a bit more, but kept forgetting. Just did it, and want to share what I learned.

It is said that desalination is costly in energy, because of the high pressure that is required. Producing 100 gal of fresh water from seawater will take about 1.4 kWh.

The Carlsbad Desalination Plant north of San Diego provides 50 million gallons a day, while drawing 38MW of continuous power. This plant costs $1 Billion to build however. So, you would want the plant to run 24/7 to produce water, not just when you have excess solar power. It is too expensive to use as a 38MW dump load.

 

[explanade]

Maybe they could have dedicated PV installed for that plant.

 

[NW-Bound]

But what does the desalination plant run on at night? Again, you do not want such an expensive asset sitting idle.

So, you feed it with coal-powered electricity when solar power is not available. Now, you are back to the problem with not having RE constantly 24/7.

 

[explanade]

Wind?

Build some windmill farms off that beautiful coast.

Or build battery banks.