martin clark
pinko bodger
not bloody likely, if you are picturing the typical constrained-install at around 1.2-2kw from 6-8 panelsYour maths is BAD
Are solar panels worth installing?
- Thread starter Rodrat
- Start date
not bloody likely, if you are picturing the typical constrained-install at around 1.2-2kw from 6-8 panels
Example -
Ten new panels giving "100%"
X years later you have 80% output from the existing installation.
You replace one panel - you have 9 x 80% plus 1 at 100% = 82% for the lot
You replace two panels - you have 8 x 80% plus 2 at 100% = 84% for the lot
You ADD one panel - you have 10 x 80% plus 1 x 100% = 90% for the lot
You ADD two panels - you have 10 x 80% plus 2 x 100% = 100% for the lot
martin clark
pinko bodger
id est, like what I rote:
Your maths is BAD. As I understand that comment.
Work your example of any number of panels that you like - replacing panels just adds back in what has been lost, which is something like 20% FOR THAT PANEL
Adding panels is NOT an option on the very great majority of roofs that I have seen.
TBH - if it was, why did they not originally fit the maximum as it would have cost relative peanuts extra, compared to the cost of installing less?
martin clark
pinko bodger
Oh, you really don't get it; and I've no interest in pursuing such an argument with a man who clearly shouts at clouds.
And yes, such is part of the mix of what I do for a living. Currently the team are trying to find 2MW of free/'renewable' input on a rather-constrained, urban site.
Bye for now.
And yes, such is part of the mix of what I do for a living. Currently the team are trying to find 2MW of free/'renewable' input on a rather-constrained, urban site.
Bye for now.
Richard Lines
pfm Member
@Rodrat - PV panels deteriorate at a rate of about 1% a year is the accepted figure so as indicated above they are still going to be giving out power for a very long time although there will be failures of some but if you buy premium panels at the outset........
Batteries deteriorate at about 3% a year (worst case and may prove to be better as automotive ones seem to do quite well).
Inverters are "consumables" - I believe the industry standard is some 7 - 8yrs between failures - don't quote me on this.
As to whether you can "run a house" well that depends on how much power you use.
PV panels will obviously produce least when you will likely need them most i.e winter
Batteries can be charged by the panels and/ or "cheap" rate electricity such as Octopus Go
Lots of people seem to be looking to invest at this time but you do need to do the maths.
Go with a well established installer.
As you can imagine Solar PV prices are currently on the up, supply and demand don't you know. There appear to be increasingly long lead times on batteries.
I would recommend most people going this route to some degree or other but first focus on insulation.
Regards
Richard
Batteries deteriorate at about 3% a year (worst case and may prove to be better as automotive ones seem to do quite well).
Inverters are "consumables" - I believe the industry standard is some 7 - 8yrs between failures - don't quote me on this.
As to whether you can "run a house" well that depends on how much power you use.
PV panels will obviously produce least when you will likely need them most i.e winter
Batteries can be charged by the panels and/ or "cheap" rate electricity such as Octopus Go
Lots of people seem to be looking to invest at this time but you do need to do the maths.
Go with a well established installer.
As you can imagine Solar PV prices are currently on the up, supply and demand don't you know. There appear to be increasingly long lead times on batteries.
I would recommend most people going this route to some degree or other but first focus on insulation.
Regards
Richard
martin clark
pinko bodger
Historical view: PV is still, roughly, around $1-1.50/watt output, installed.
That's <1/10th where it was 1-12 yrs ago, and 1/50th where it was, 5yrs before that.
That's <1/10th where it was 1-12 yrs ago, and 1/50th where it was, 5yrs before that.
richardg
Admonishtrator
How does that work? I thought it had to go to the battery first?
martin clark
pinko bodger
@davidsrsb, I've posted on that within the last week or two: the result will actually be a hybrid solar-thermal/ solar-PV; using thermal collectors can drive an absorption-refrigeration cycle very, very efficiently; the PV content will drive the pumps, control, and add to total CoP. I've been working with a group looking at this over the last decade, even in the UK climate.
(nb - it works, it works well, the issue is the always-slow change in attitudes towards 'novel systems', skepticism until seen/proven to work elsewhere [on someone else's dime] - though everyone says they want to be first, professional indemnity insurances etc... oh, all the normal human failings...)
(nb - it works, it works well, the issue is the always-slow change in attitudes towards 'novel systems', skepticism until seen/proven to work elsewhere [on someone else's dime] - though everyone says they want to be first, professional indemnity insurances etc... oh, all the normal human failings...)
klfrs
chill out
davidsrsb
pfm Member
Someone actually managed to get a patent on using the air conditioning compressor to pre heat incoming water for domestic hot water supply
Bungalows, due to surface area to volume will always be less efficient than houses and once you have put in thick loft insulation etc ti seems like there is little more that can be done, so I understand where you are coming from.
However, I would add a few points as this is an area I am looking to do some research into (and have already investigated and experimented in quite a lot).
The UK housing stock contains many houses of the type that you are living in.
To reduce fuel usage and heating costs (many people ide of the cold in older houses each winter), houses of this type need to be insulated further (government or private funded).
Just adding insulation is not the answer as comparatively more and more heat is lost through air leakage. And incidentally is why mathematical models of houses are so difficult and predictions of the cost effectiveness of just insulation are generally very wrong.
Adding more insulation and sealing air gaps is a better approach but is still not the full answer as you would then encourage poor air quality and damp in the building.
Adding more insulation, sealing air gaps and adding a mechanical heat recovery ventilation system (MHVR to provide fresh air whilst taking thermal energy out of the outgoing dirty air and putting it into the incoming cooler air) is a potential solution.
Each house varies in terms of what would be best due to orientation, local climate, build type and quality and previous work, so expert help is going to be required for more and more houses.
In your case it sounds like external insulation (if applicable (appropriate space, render etc)), with sealing of air gaps and a MHVR system could provide you with a much cheaper to heat house (would also remain cooler in heat waves), be more comfortable to live in and whenever you need to to change your heating system, it would need a lower capacity system and hence be cheaper to purchase.
Total cost for the above would be similar to your solar panel solution.
But I fully understand why people want to go for solar panels (local energy generation is great) or ground source heat pumps, or air source heat pumps etc as that is what is being marketed and is far simpler than getting expert help to better understand what may be the cheapest (short and or long term) solution for any given house.
@martin clark anything that I have missed?
gingermrkettle
Deep vein trombonist
Our solar panels (SunPower Maxeon) and inverter (SolarEdge) have a 25 year warranty, our Tesla Powerwall has a useful stated life well in excess of 10 years with normal charge/discharge use. Battery life in EVs is more a function of the amount of rapid DC charging, trickle charging of batteries from stuff like V2G actually extends lifespan from current studies.
And while we have put in MVHR here, the cost of a retrofit was not that much less than the solar installation and with thoughtful usage the solar will have more impact on total energy usage.
Bodiddly
pfm Member
I'm currently waiting for solar panels and battery to be installed. A big factor in my decision is that I have an electric car, and the tariff I pay to charge it up overnight is very cheap (Octopus Go), like the old Economy 7. Obviously charging it up using solar power will cost even less; and I'll no doubt feel really content driving round powered by sunlight.
I'm hoping that having a battery will mean that even when the solar power is insufficient to charge it fully, I can top it up overnight using the low tariff, so that the electricity I use during the day will cost much less than the normal tariff.
When I placed the order in June I estimated that the pay period would be between 15 and 20 years. With the recently announced increase in the cost of electricity this will no doubt come down. Having said that, the financial case was not the main reason for going down this route. I was 70 this year, so there's a good chance that I will have shuffled off this mortal coil before the investment has paid for itself. The main reason was to do something tangible to reduce my carbon footprint. Also I realised that I can't take my money with me, or spend it all on hi-fi, so I may as well do something useful with it.
I'm hoping that having a battery will mean that even when the solar power is insufficient to charge it fully, I can top it up overnight using the low tariff, so that the electricity I use during the day will cost much less than the normal tariff.
When I placed the order in June I estimated that the pay period would be between 15 and 20 years. With the recently announced increase in the cost of electricity this will no doubt come down. Having said that, the financial case was not the main reason for going down this route. I was 70 this year, so there's a good chance that I will have shuffled off this mortal coil before the investment has paid for itself. The main reason was to do something tangible to reduce my carbon footprint. Also I realised that I can't take my money with me, or spend it all on hi-fi, so I may as well do something useful with it.
PsB
Citizen of Nowhere™
Interesting. Did you find that using thermal panels + absorption worked better than using PV panels + heat pump for the sanitary hot water, and if so which refrigerants did you consider? I am going to renovate a house soon, PV panels will be part of the overall energy system, think we're sorted out the heating/AC side, but I'm not sure how to handle the hot water side.
tpetsch
...The rhythm has Control
On top of everything mentioned here I'd also be concerned about the quality of installation of the panels on my roof, all the holes drilled on an otherwise sealed from the elements shingled roof. The solar panels may last 20 years but will my roof not leak from all the mounting holes? ...and what about roof maintenance? All those panels will need to be removed and reinstalled.