EEVblog #1086 - 5 year Solar Power Payback?

[EEVblog]

Dave looks at the 5 year data on his 3kW home solar power system. What was the payback period? And will adding a Tesla Powerwall 2 lithium ion battery energy storage solution be worthwhile?

[Brumby]

Interesting results - and, yes, the feed in tariffs around Sydney haven't been particularly attractive.

I have contemplated going down this path, but getting to know what gear is out there with its pros and cons is something that I baulk at.  Knowing what to believe in online reviews is one challenge.

Any recommendations?  (For reliable information sources)

[EEVblog]

Interesting results - and, yes, the feed in tariffs around Sydney haven't been particularly attractive.
I have contemplated going down this path, but getting to know what gear is out there with its pros and cons is something that I baulk at.  Knowing what to believe in online reviews is one challenge.
Any recommendations?  (For reliable information sources)

In terms of what? brands or panels and inverters? installation companies?
I would stress over either.

[orion242]

I think you also need to look at how many people keep their homes =>10yrs.  If most move under that, there is little sense in installing it.

Have an off the grid out building myself, but doubt the costs will make sense in a decade if ever factoring maintenance.

[caswal]

Dave, have you seen the Australian Z-Cell home battery storage: https://www.zcell.com/

Completely different chemistry/design to Li-Ion cells. They have started trails in Aus, maybe see if you can get one to play with?

[Brumby]

In terms of what? brands or panels

Yes.

and inverters?

Yes.

installation companies?

Yes.

I would stress over either.

[aqarwaen]

dave why you dont build your own battery,to store  all that electricity generated by solar panels?
you could use old smartphones  batteries sent by your viewers,laptop batteries
or  cheap lithium batteries made in china.

it would be any  intresting video,if you decided to make it your own instead..

[SeanB]

Went to Makro today, and they have done the whole parking lot in solar panels, providing shade and power at the same time. There is a corner with a 11kv transformer and control gear to handle this load, and there is a wall of inverters ( one per parking bay panel set) to do the actual work.  Note how they are keeping the inverters cool, using a pair of massive industrial floor standing fans bolted to the concrete to move air over the inverters.  The day today is quite cool, only 27C ambient as I drove around, so those fans are definitely going to be needed in summer when it goes over 30c and humidity goes to the 100% mark. I think the payback they have is pretty good, seeing as the parking lot is pretty big, and they also have done the roof of the complex in solar panels as well, plus the lighting has been changed to LED throughout the store as well, and they have installed all new energy efficient fridges and freezers as well, grouping them into a single cool zone, and another frozen zone, with insulated doors all round on the customer side display shelves.

[nixfu]

This makes the whole building your own Homebrew PowerWall battery bank using free/recycled 18650's look more and more reasonable. See: Youtuber: HBPowerwall.




ALSO, I would suggest you do an analysis of using a traditional large lead-acid or AGM battery storage system cost and see if that has a better payoff than the fancy new lithium based ones.  I bet that would be a much better way to get payoff of your excess daytime energy production.

[KrudyZ]

I think you also need to look at how many people keep their homes =>10yrs.  If most move under that, there is little sense in installing it.

That logic seems a bit flawed. Presumably, having a lower expected electricity bill would be a value add for the new owner as well, so it should increase the resell value of the home.

[coppice]

I think you also need to look at how many people keep their homes =>10yrs.  If most move under that, there is little sense in installing it.

That logic seems a bit flawed. Presumably, having a lower expected electricity bill would be a value add for the new owner as well, so it should increase the resell value of the home.

Property agents say few buyers see value in solar panels, so why would they see value in battery packs?

[orion242]

You rarely get the full value out of a home improvement when you sell in my experience.  Put a new roof on my current house.  Is the next buyer going to give me an extra 10K?  Doubtful, they will expect the roof doesn't leak...

Even then, why would I shell out the coin for something that may not break even before I sell from a financial point of view?  Save the earth, solar nerd, good feed in rates, ect sure.  Massive tax credits, maybe.  Till I get to the house I plan on dying in, cannot see shelling out the coin myself unless the payback math is ~5yrs or less.

[ChunkyPastaSauce]

Lot of people are going to have large kwh batteries packs parked in garages or connected lots for large portions of the day.... likely to go a long way if standardized.

[maelli]

4000kwh per year, not bad for a 3.0kW system.
My 8.7kW system will give me (first 12 months are soon over) around 10000kwh per year.


Difference Switzerland to Australia apparently 16%.

I also said no to battery, my reasons are different: in winter we need a lot juice, PV production is low.
In summer the opposite.  summer/winter batteries do not exist.

Did you consider installing an electric (heat pump) water heater?
I have one and have it connected to a relay in the solar inverter. Over 800W PV, then heater starts.
Nice side effect: these things dry the air in the basement.

[tszaboo]

Interesting results - and, yes, the feed in tariffs around Sydney haven't been particularly attractive.

I have contemplated going down this path, but getting to know what gear is out there with its pros and cons is something that I baulk at.  Knowing what to believe in online reviews is one challenge.

Any recommendations?  (For reliable information sources)

Inverters come with long warranty, which are at least 10 years, so they will pay for themselves by then, or if it breaks, you get it repaired under warranty. If you get an inverter from the big 4 (at least here), SMA, Fronius, ABB or SolarEdge, it is very unlikely to make a bad deal. I've seen statistics for 6000 solar installations (no, not panels, these are separate sites), and very few broken inverter. This is not consumer stuff. Also the same goes for the panels themselves. Even the Chinese ones are OK. It is typically not the panel which goes wrong, it is the frames rusting, leaking, and installers with two left hands. It is really hard, or you need a very bad luck to make a bad deal for solar. Or you need to try your best to  select the worst brands.
Also, just make sure it is not shaded, even partial shading is bad. The guy, who was working next to me was training an AI to find installations with shading from the data. And no micro inverters. They dont make any sense financially, but that is the part that actually going to break. Why? Because to keep them competitive, they need to keep the cost down. It is also installed behind the panel (hot), it has to be waterproof (no ventilation), so it is an OK idea turned bad.

You rarely get the full value out of a home improvement when you sell in my experience.  Put a new roof on my current house.  Is the next buyer going to give me an extra 10K?  Doubtful, they will expect the roof doesn't leak...

Even then, why would I shell out the coin for something that may not break even before I sell from a financial point of view?  Save the earth, solar nerd, good feed in rates, ect sure.  Massive tax credits, maybe.  Till I get to the house I plan on dying in, cannot see shelling out the coin myself unless the payback math is ~5yrs or less.

Yeah, so you should just let your home rot away, because it is temporary anyway. BTW everything in this word is temporary.

[coppice]

You rarely get the full value out of a home improvement when you sell in my experience.  Put a new roof on my current house.  Is the next buyer going to give me an extra 10K?  Doubtful, they will expect the roof doesn't leak...

Even then, why would I shell out the coin for something that may not break even before I sell from a financial point of view?  Save the earth, solar nerd, good feed in rates, ect sure.  Massive tax credits, maybe.  Till I get to the house I plan on dying in, cannot see shelling out the coin myself unless the payback math is ~5yrs or less.

Yeah, so you should just let your home rot away, because it is temporary anyway. BTW everything in this word is temporary.

No, you need to keep your home serviceable, both so its pleasant to live in and and so its saleable. However any expenditure beyond that has to be viewed in the light of how long you expect to live in the same home. If you are pretty sure you're going to be there a long time, a lot of expensive features make sense. If you are likely to move in a few years, perhaps you should keep the cash to splash out on a future home that might be more long term.

[thm_w]

No, you need to keep your home serviceable, both so its pleasant to live in and and so its saleable. However any expenditure beyond that has to be viewed in the light of how long you expect to live in the same home. If you are pretty sure you're going to be there a long time, a lot of expensive features make sense. If you are likely to move in a few years, perhaps you should keep the cash to splash out on a future home that might be more long term.

Sure but most people aren't expecting to move in a few years, if you were it would make sense to save the money to install solar on your new home. The average time spent per home in Canada is ~15 years.

Our payout is a bit better, 10c/kWh and cost for electricity is 13c/kWh. But payback here is more like 20 years, so its not worth it yet, especially since our energy is clean already.

[coppice]

Sure but most people aren't expecting to move in a few years.

I don't know how much this varies with countries, but in the UK the average ownership of a property seems to be only 5 or 6 years. I've always found that figure puzzlingly low, but its what the land registry people say.

[orion242]

Looks like the US most people move 11 times in their life, though its more often when they younger.  Average between is going to be 10yrs or less if that's the case.

[Rutherfordium]

Today on the east coast of Canada CBC radio was having a phone in to ask people whether we should force new homes to come with solar panels (apparently something starting in 2020 in California).  I rolled my eyes, and I hadn't even seen the numbers from this video, from a nearly ideal (at least compared to the precipitous maritimes) location.

[NiHaoMike]

Nissan Leaf battery modules are $200/kWh for a few modules, even less in bulk.

[IanMacdonald]

This makes the whole building your own Homebrew PowerWall battery bank using free/recycled 18650's look more and more reasonable. See: Youtuber: HBPowerwall.

Glad I don't live next door, or I'd be thinking in terms of one of these..

[EEVblog]

No, you need to keep your home serviceable, both so its pleasant to live in and and so its saleable. However any expenditure beyond that has to be viewed in the light of how long you expect to live in the same home. If you are pretty sure you're going to be there a long time, a lot of expensive features make sense. If you are likely to move in a few years, perhaps you should keep the cash to splash out on a future home that might be more long term.

There is something coming on this front, for people who need a non-permanent power storage solution. I'm hoping to get a prototype unit this year.
I had dinner with the designer last month and a good chat about the patented technical solution they have come up with.

[EEVblog]

ALSO, I would suggest you do an analysis of using a traditional large lead-acid or AGM battery storage system cost and see if that has a better payoff than the fancy new lithium based ones.  I bet that would be a much better way to get payoff of your excess daytime energy production.

They are not designed for deep daily discharge like is needed in my case.

[EEVblog]

dave why you dont build your own battery,to store  all that electricity generated by solar panels?
you could use old smartphones  batteries sent by your viewers,laptop batteries
or  cheap lithium batteries made in china.
it would be any  intresting video,if you decided to make it your own instead..

It would takes many months of almost full time work to design and build such a solution for a video.
The problem with people seeing what others have done in videos and say "why don't you do that", is they don't realise the massive amount of work these people have done behind the scenes in order to do that. HBpowerwall is one such example, he's been working on that system for a couple of years.