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Are solar panels worth installing?

Rodrat

pfm Member
Given the current energy crisis is there any financial benefit to spending 16-20k on panels with a battery backup? From my limited reading you can’t run a house completely anyway.
 
well make sure you dont lease them as can cause massive problems reselling house

and something i didnt know

Common sense might indicate that since solar panels rely on sunlight to function, warmer air would help solar panels run more efficiently or with more power, but that’s not the case. Although solar panels use sunlight to produce energy, they do not require heat in any way. In fact, solar panels may run about 10 to 25 percent less efficient on warm, dry days reaching 90 degrees Fahrenheit or higher.

The hotter the ambient air becomes, the less efficient your solar panels will be. When temperatures reach triple digits, most panels will start to lose about one percent of peak output for every additional degree the temperature increases. Homeowners who experience high temperatures during the summer can understand how their panels will respond by checking the temperature coefficient of their solar panel system.

https://energysavingpros.com/solar-...panels use sunlight,your solar panels will be.
 
Interested to learn more here. I've heard there are reliability issues, so once out of warranty how much does it cost to send someone up on the roof to sort it?

And how long do the batteries last?
 
I've been thinking about this too. It depends what you mean by "worth installing". There is simple return on investment, but also it may also be worthwhile to you to ensure a constant supply in case of power cuts, and to reduce your carbon consumption for ethical reasons.
 
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Interested to learn more here. I've heard there are reliability issues, so once out of warranty how much does it cost to send someone up on the roof to sort it?

And how long do the batteries last?
A good question. First you need the number of charge cycles that the battery can take. For Li-ion it has been around 1000 cycles but car battery design might have improved on that. So if you fully discharge a battery daily and then recharge it to max/full thats a 1000 days/3 years. In practice you may get longer if the battery is only partially discharged on some days so if you discharge 25% and recharge for 4 days that'll count as 1 cycle.

You'll also have to budget for a replacement converter the box that turns the DC into AC to feed into the Grid. When I asked about this I was told 'about' 5 years. Then once the panels are no longer effective whats the price of removal/repair/replacement.

I looked into this in the early days years ago when the FIT was good and decided at the time that I'd get a better return from the stock market.The panels also spoil the look of 'traditional' properties.

I should be careful of knee jerk responses. Today gas prices are 4 times what they have been hence the high cost of energy but it will come down in price. The stock market is doing well despite all the doom and gloom that the BBC and press are spreading. As the market tends to look at whats happening around the globe about 6 months ahead the confidence is high that after some rocky times things will improve.

DV
 
Thing is after 1000 charges the battery is not useless. So you could just add another one to make up for its inefficiency, then another one etc.
 
A good question. First you need the number of charge cycles that the battery can take. For Li-ion it has been around 1000 cycles but car battery design might have improved on that. So if you fully discharge a battery daily and then recharge it to max/full thats a 1000 days/3 years. In practice you may get longer if the battery is only partially discharged on some days so if you discharge 25% and recharge for 4 days that'll count as 1 cycle.
But if you discharge by 25%, then recharge to 100%, that's a charge cycle too.
 
A good question. First you need the number of charge cycles that the battery can take. For Li-ion it has been around 1000 cycles but car battery design might have improved on that. So if you fully discharge a battery daily and then recharge it to max/full thats a 1000 days/3 years. In practice you may get longer if the battery is only partially discharged on some days so if you discharge 25% and recharge for 4 days that'll count as 1 cycle.
xx 12 years & batteries are still fine

You'll also have to budget for a replacement converter the box that turns the DC into AC to feed into the Grid. When I asked about this I was told 'about' 5 years. Then once the panels are no longer effective whats the price of removal/repair/replacement.
xx life time warranty 12years ago & if they fail swap out for latest designs

I looked into this in the early days years ago when the FIT was good and decided at the time that I'd get a better return from the stock market.The panels also spoil the look of 'traditional' properties.
XX BIPV built in PV almost Invisible
DV
xx 10 years X £1500 energy use = £15,000 saved
10 years X £1500 export FIT tarrif = £ 15,000 earned
cost £9000 to install ( half of a annual bill next year ) & earned £30k with another 15years earnings

just checked today on mobile app on the Inverter sunny day in scotland and exporting 90% to the grid
Battery pack 95% charged , currently several days energy useage on tap
The sun never sends you a Bill
 
All of the kit mentioned has a life and performance gradually declines from day one. Which means that the maths involved is far from simple.

The LIKELY economic replacement period for the panels themselves is around 20 years.

Anyone want to take a punt on UK electricity prices for the next 5? 10? 20 years?

Anyone know anything about current technology domestic-sized wind turbine economics?
 
I would look into insulating (and increasing solar shading if possible and appropriate) your house more effectively if that has not been done already.

As the insulation will reduce the heating costs of the house in winter and reduce over heating in the summer (including solar shading makes the extra insulation even more effective by stopping the strong sunlight from penetrating and over heating and damaging the internals of the building).

By doing this the cost of replacing a heating system in the future will be much cheaper you will need to supply less energy and your heating bills (and cooling if you use aircon) will will also be less for the lifetime of the building.

Many years ago we did many many insulation and solar shading upgrades to our house and have found them to be very effective in summer and in winter.

For further reading this is the gold standard:

https://blog.passivehouse-international.org/the-enerphit-standard-how-does-it-phit-in/#:~:text=The EnerPHit standard is a,House buildings are known for.
 
The hotter the ambient air becomes, the less efficient your solar panels will be.

I also read about this recently and was surprised as it seems counter-intuitive. Okay, this summer may be exceptional but if this becomes more than occasional it must affect the cost/return calc's. I got a survey just before the plug was pulled on the initial feed-in tariff. Its successor was still viable but I never followed it up (partly because I could accommodate 1 panel less than the optimum and I was also concerned at the time about any effects on my hifi kit). Full south facing roof, too.

Not sure why the extra expense of a battery is a good idea in normal circumstances as what you don't use is still fed back for some paltry rebate, and I'd imagine any excess would only occur during these hot months.
 
The LIKELY economic replacement period for the panels themselves is around 20 years.

This is not true; these days PV panels - even the cheap domestic installs - are rated 25yrs life to de-rate to a minimum of 80% of rated output. It's a very, very mature technology - as is their production.

So at ~ 20years what you do, perhaps, is just tack-on another panel; maybe two.

Actual useful panel life has long proven to be well over 40yrs, average. And that's for lower-efficacy stuff made in the 70s...
 
60+ years no problem in Space 20-50years on your house
The first space application of solar panels came in 1958, when the Vanguard I satellite was launched. Sputnik 3, and Explorer III

1839 19-year-old physicist named Edmond Becquerel. While working on the coating of platinum electrodes using silver chloride, he discovered a rise in voltage on exposure to light. This effect was named as photovoltaic effect. 1883, the first proper photovoltaic cell was devised by Charles Fritts

Charles Fritts. He installed the world’s first solar rooftop system in New York, in 1884, way before solar started becoming a common word.
 
1950’s bunglehole which is never going to be that great at being energy efficient. Cavity wall, double glazing and thick loft insulation so not much more we can do. The advantage us a large roof area for panels. However the dilemma is whether it is likely to be cost neutral over the next 15 years or not. If it is neutral then the environment gains would tip it in favour. It also finding an installer who isn’t the equivalent of the rip off double glazing firms.
 


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