Looking into solar for the house today - PeachParts Mercedes-Benz Forum

elchivito · #1 12-21-2015, 10:31 AM

A guy from Elon Musk's outfit, Solar City is coming out in a while to pitch me numbers on solar panels for the house. I've read the pros and cons of buying vs. leasing and am thinking so far about leasing.
To buy is still a huge outlay after the tax credits
Once you buy the system is yours, something breaks it's your problem.
Leasing is long term 20-30 years
No cash outlay up front, system is guaranteed for the term
I've read they are now offering a system incorporating their Tesla battery technology for power outages. A big issue here.
Not worried about the iffyness of a leased system on a home that may be for sale. This property will never be for sale in my or my wife and kids' lifetimes.

We'll see what he says. I am hoping he isn't planning on a water softener type sales pitch. Going to tell him from the get-go that I only have an hour free and do not plan to sign anything today. If he's not good with that I'll turn the dogs loose.
Any thoughts?

t walgamuth · #2 12-21-2015, 10:32 AM

you looking at a electric generating system or a hot air or hot water system?

elchivito · #3 12-21-2015, 10:41 AM

Electric. I have a pal in town who converted and his meter spins in reverse about half the time. He gets a decent yearly check for his excess power.

barry12345 · #4 12-21-2015, 11:19 AM

Only thing is how does the loss of efficiency of the solar cells play out over time? Expected years of service until they deteriorate to unacceptable levels.

I know basically nothing about solar cells but have experienced this with our fluid panels. I think that the uv component in sunlight probably eventually gets everything.

Our panels have black chrome as the collection medium itself. Glass covered as I pretty well expected that plastic covers would deteriorate faster.

Although glass also weathers but otherwise seems to stay stable. I also felt that as the glass surface weathered with the years. The refraction of the sunlight from the surface as the suns angle to the panels increased grew substantially.

I do not know who cleans the surface in your geographical area periodically or if the need is there. Perhaps rainfall is enough. What kind of roof they are mounted on and the angle may or may not make a difference if this is a requirement.

I also want to mention that I am all for the use of solar devices of all types. But they have a lifespan that has to be considered and that is sometimes overlooked. Or not taken into consideration enough. I would like to see a graphed expected deterioration curve to base my initial system size on. Plus some other factors like the costs amortized.

.The suppliers knowing this suprises me that they have leases as well. Of course that is just paper they can sell. So lease versus outright purchase would have to be examined very carefully.

You probably have already done your homework and what I am mentioning may be totally irrelevant and just plain redundant. Even if the salesperson is totally up front and really knowledgeable an hour might not be enough time to get all the answers you may want. We live in eastern Canada and we would have really gained far more by being further south. Still our system had paid itself off in a not unreasonable time frame and we had a pile of free years until it deteriorated substantially. Purchased commercially and installed by them would have cost us perhaps five times more and it may have been a horse race to see a proper payback.

The future may be a panel of cells that collect and convert the energy to electricity and incorporate a system to take any usable excess heat away as well to use. I suspect without actually knowing they might run reasonable hot.

I have the sputtering high vacuum equipment to make them. I have never investigated this though properly. I have heard that the materials used in this case for the sputtering deposition of layers of material onto the glass or similar substrate is very expensive and there are proprietary secrets I suspect to extend their usable lifespan. So it is not something to play around with and at small volumes for self usage quality control is probably a nightmare.

I have a suspicion that the modern cell that has evolved is both far more efficient and probably has a much longer usable lifespan than the earlier ones. So much so that I could not produce them anyways without some closely held information. That research has cost at least millions to obtain. So again it in all probability is closely held.

As I sit here thinking the dual purpose panel is not practical as many materials used in the sputtering may not do well at elevated temperatures. The same as many solid state devices. In fact the inverse is true perhaps where water cooling might be a signifigant overall benifit instead. So todays solar cell may still be a compromise to some extent to keep the already high costs and complexity of installation down . Anyways what exists today is here to stay and will be improved I suspect with time.

One thing I might add. Since you can sell electricity back into the grid today more storage that is usually expensive is not a great issue. Yet if you even desire more.

At one time years ago we used to get the large lead acid cells that provided the back up systems of the telephone company. Just for the scrap prices when they were cycled out of service. These cells were about three feet high and perhaps two feet in depth and about a foot wide. They were still quite serviceable and we figured they just had a periodic cycle change out perhaps not based on condition. The beauty being they actually cost nothing as you could resell them as scrap and even make a few dollars if scrap was high at the time when you were finished with them. Each one being a very heavy single cell. Depending on your location and local company policies etc. If you have the right connections you might obtain some. Even back then some companies removed the electrolite and some did not before you got them.

Thinking back from today. The amount of connections we had and what we could pull off pretty consistently seems remarkable. I was always able to get and incorporate some materials in new construction as long as our engineer approved them. Times have changes so much I get little to anything much cheaper for the last ten years. The surplus stuff does not seem to be as readily available in our region.

i

Maki · #5 12-21-2015, 11:20 AM

Have you looked into solar pond technology? I saw one in operation in Israel 30 years ago and think the idea is pretty ingenious. It's more maintenance-intensive than PV but it produces energy around the clock.

Here's a link to literature on a UTEP project:

pond_html

t walgamuth · #6 12-21-2015, 11:33 AM

Rain does not clean my sloping glass...in fact when the farmers are in the fields it rains mud.

tbomachines · #7 12-21-2015, 11:36 AM

Quote:

Originally Posted by t walgamuth

Rain does not clean my sloping glass...in fact when the farmers are in the fields it rains mud.

Man, I never knew a **** storm was really a thing

Sent from an abacus

P.C. · #8 12-21-2015, 01:09 PM

I would want to know if the lease is transferable to future property owners, even if you don't contemplate sale of the house.

engatwork · #9 12-21-2015, 01:30 PM

If he sells you a Tesla to go with it get the S model.

elchivito · #10 12-21-2015, 01:58 PM

Quote:

Originally Posted by P.C.

I would want to know if the lease is transferable to future property owners, even if you don't contemplate sale of the house.

It is. I'm going over the details now. My situation isn't ideal. I have a lot of old trees close to the house. Without any modifications at all he estimates I'll be able to generate about a third of my annual Kwh usage.

P.C. · #11 12-21-2015, 02:03 PM

Quote:

Originally Posted by elchivito

It is. I'm going over the details now. My situation isn't ideal. I have a lot of old trees close to the house. Without any modifications at all he estimates I'll be able to generate about a third of my annual Kwh usage.

I have an idea:

CarpeDiem51392 · #12 12-21-2015, 02:28 PM

I've heard this is actually a serious issue with solar panels, the dust that settles on them reduces efficiency. This issue is intensified in areas that get little rain, even though they may be very sunny. One of the reasons solar panels may be more suited to rainy areas than say a dessert. Just some thoughts what do I know right

Quote:

Originally Posted by t walgamuth

Rain does not clean my sloping glass...in fact when the farmers are in the fields it rains mud.

t walgamuth · #13 12-21-2015, 02:44 PM

Actually it may clean them but it also muddies them so it may be a wash (heh heh!)

elchivito · #14 12-21-2015, 02:51 PM

Quote:

Originally Posted by P.C.

I have an idea:

My idea too, but it's important to realize trees are a commodity in the desert. Hard to figure if their removal for more solar generation would be a bigger benefit than the shading and cooling they provide in summer. My house is adobe, modern on one half and very old on the other but earthen on both sides. It operates on the thermal mass cycle. There is roughly a 12 hour lag between the adobe's absorption of solar energy from the outside and its pentration to the inside. Deciduous trees allow the house to receive more sunshine in the winter and less in the summer; exactly what I want. It worries me a bit to screw around with that balance by cutting back or down enough trees to allow more sun on the roof to increase the number of panels. If I can geerate more power with a less shady roof will I just need more power to run mechanical cooling which I now rarely use? A conundrum.

dynalow · #15 12-21-2015, 03:43 PM

Quote:

Originally Posted by engatwork

If he sells you a Tesla to go with it get the S model.

One passed by me yesterday. NJ (Vanity) plate: "MAXPOWR".