Life expectancy of a domestic PV system

[sophiecentaur]

We are buying a house which has a Ten Panel PV installation that has ben running since 2011. The installation is effectively for free. I have seen several figures about the expected reduction in output power but I'm wondering about other processes, apart from the cells getting old, that could affect how many more years of use I can expect. This site is on the Thames Estuary in UK (52°N ish) and the roof slopes to the South. The ten panel installation seems to be a standard package and there is room for a lot more - if the existing system performance is encouraging. Unfortunately there's no one to ask about it as it's a Probate sale.

There's another issue with the tile roof which will need attention in the not too distant future. Accepted wisdom seems to indicate that the cost of removing and replacing the panels during the roofing operation would be significant. Now, those tiles have been protected to some extent for 13 years by the panels; would that affect their probable life expectancy?. HAs anyone any experience of this and is there any useful advice I need. I am well aware that I should 'do things properly' but the house needs a fair bit of money spent and . . .

Feel free to discuss and tell me I'm just an old skinflint.

 

[Baluncore]

The tile roof will have been protected by the panels.

How many kW of grid-tie inverter?
How many strings can it support?
How many strings are now installed?
Does the wind and rain keep it clean?

Panels are cheap, the supporting racks, and the electricians to do the installation are expensive.

Keep using it while it works. If it fails, replace it with an economic investment bundle, new everything. If you need more power and have a spare string, add one string to the existing system.

If you buy the house, make sure you insure the panels with the house. A hailstorm, hurricane, or an SS Richard Montgomery, could see one or two panels being damaged by ice or debris.
The repair procedure should be to replace all with a matched set of new panels. Mixed and unmatched strings are a real problem when the currents and MPP are different. Replacing one panel can physically cause earth leakage in others, so avoid unnecessary disturbance.

 

[.Scott]

Beware of that "for free" installation.
A few years ago I asked my neighbor about his roof solar panels. They had gotten dirty enough to clearly impact their power output and it would have been a simple thing to visit the roof with a power washer and get them back to normal.

His answer surprised me. Although the panels had been there for years, they were still not hooked up. Basically, the company that installed them had "claimed" their roof in exchange for "free installation", but they were not going to start service until electric prices were high enough for them to make a profit.

 

[Averagesupernova]

Beware of that "for free" installation.
A few years ago I asked my neighbor about his roof solar panels. They had gotten dirty enough to clearly impact their power output and it would have been a simple thing to visit the roof with a power washer and get them back to normal.

His answer surprised me. Although the panels had been there for years, they were still not hooked up. Basically, the company that installed them had "claimed" their roof in exchange for "free installation", but they were not going to start service until electric prices were high enough for them to make a profit.

So who's liability is it if roof work is needed?

 

[.Scott]

So who's liability is it if roof work is needed?

The "claim" they have is probably just the right to maintain their solar panels. It's still my neighbor's roof - so he would still be responsible for it's upkeep.

 

[Averagesupernova]

The "claim" they have is probably just the right to maintain their solar panels. It's still my neighbor's roof - so he would still be responsible for it's upkeep.

Yes, I would assume that their presence keeps anyone else's solar off the roof. So if they're not hooked up what benefit is it to the neighbor to have them there? There is a significant cost involved to have to deal with them if roof work is needed.
-
We have similar situations where a wind tower company signs you up for leasing land to them for wind towers. They get around to putting them up whenever they feel like it. You collect no rent until the tower is there and cannot lease to anyone else. These would be large scale wind turbines. Small scale wind power is 100% owned by the property owner as is solar. The small scale turbines are still tall towers. Just not as tall, and smaller turbines.

 

[sophiecentaur]

It's still my neighbor's roof - so he would still be responsible for it's upkeep.

He should get some posh, headed notepaper and inform them that a new maintenance charge will be levied and make them a competitive offer for the installation as-is.

 

[.Scott]

He should get some posh, headed notepaper and inform them that a new maintenance charge will be levied and make them a competitive offer for the installation as-is.

You mean a competitive offer to purchase the installation? What he really needs is to purchase the solar collection rights back for his own roof.

 

[sophiecentaur]

Beware of that "for free" installation.

It was not a 'for free' installation. It was part of the house but had not changed the 'going rate' purchase price of the house.

The "claim" they have is probably just the right to maintain their solar panels. It's still my neighbor's roof - so he would still be responsible for it's upkeep.

The details of the contract would be needed but, in UK at least, the push for sustainable power could make the situation of interest to the MP. The terms are certainly not what HMG wanted, I'm sure. Can you imagine the government being more interested in appearances than fact?

 

[.Scott]

It was not a 'for free' installation. It was part of the house but had not changed the 'going rate' purchase price of the house.

If the situation is as it was described to me, the value of the property has decreased. It sounds to me as though he exchanged a portion of his property rights for something that will be of little use to him or any prospective buyer until the PV company decides to use it. My expectation is that this is likely to appear as some kind of lien on his property.

 

[.Scott]

The details of the contract would be needed but, in UK at least, the push for sustainable power could make the situation of interest to the MP. The terms are certainly not what HMG wanted, I'm sure. Can you imagine the government being more interested in appearances than fact?

From this description of life in the UK, the MP would have an additional motive to act. The homeowner has likely been lost his option of putting up his own system on his roof.

In fact, I (and my neighbor) live in New Hampshire, the "Live Free or Die" state - where there is low tolerance for government interference.

 

[Ken Fabian]

Panels themselves are reliable with long life (greater than 30 years). The more common "string" inverter life appears to be a lot shorter than that of panels, perhaps half that. Micro-inverters (one for each panel) appear to last longer, potentially as long as the panels. Inverter technology is still in flux and can be expected to continue to improve and hopefully durability will improve; what we have now may not be what future home solar uses.

As an aside, as an Australian I can also expect that the electricity the grid provides will be dominated by solar and wind within a few more years and will have lower emissions whether people care about emissions or not, and will do it more cost effectively than domestic rooftops.

Ours (with batteries) works very effectively and whilst it had steep up front costs it has still worked out being cost effective; most of our electricity charge is 'connection/service availability' and draws very little electricity. (Financing things that are more expensive up front but cheaper overall is a major impediment). "Feed-in" has largely ceased being subsidised - the excess doesn't earn much now for home owners - and the benefits are in reduced purchase of electricity and providing power during outages, which can at times save expensive fridges full of food.

 

[sophiecentaur]

Ours (with batteries) works very effectively

Our smart meter spends a lot of time showing a sniff of 'exporting' so I guess the battery charges usefully at the time. The reported Import power is low all the time. But it IS near midsummer so you'd expect that; Very little gas has been used either. (No AirCon to take useful energy.)

Your mention of the Fridge contents was useful. The battery should last to give a day's backup for the frozen meat and fish, at least. Also it should keep the CH alive, too.

There's a small practical problem in that I can't find my clamp meter since we moved in. That would help a lot but I don't want to buy another one; I'll have to wait for my new workshop to be finished and installed, giving a chance to unpack a lot of my toys.