Solar Panels - practicality and time to return on investment?

Cluelessabouttax

My partner and I are deep into the conveyancing process of buying a house which is an older property but not listed. We got a level 3 survey which showed that the roofing tiles on the oldest part of the house were on their last legs and that the boiler although functional was 20 years old, inefficient and should be replaced. Depending on a few factors (chiefly if the vendors will agree to our reducing our offer to match the cost of the major works required within a year) we will still proceed with buying the house. 

The above combined with the surveyors remarks that the government is keen to phase out gas boilers and the rising price of gas has got me thinking that if we proceed with the purchase and get the roof repaired we should seriously consider having solar panels installed and the hot water and electrical systems converted to solar power. A large section of the roofing on the house is south facing and there should be more than sufficient square meterage available. While we both work outside of the home our ours and days can be highly variable so I think we would be at home enough to make solar energy worthwhile 

What are others experiences of using solar power and selling energy back to the grid etc? How is the installation, maintenance and how long did it take for the panels to pay off their initial outlay? Also thinking further towards the future do solar panels generate sufficient electricity for electrical vehicle charging? 

Magnitio

When a roof is in need of work, it is an ideal time to instal solar panels. The answers to many of your other questions will depend on:

- how large is the available roof for panel installation?

- how well insulated is the house?

- if you have an EV, what mileage are you likely to cover and will all your charging be at home?

Hexane

Early adopters of solar power achieved extremely good returns, and some paid off their initial outlay in as little as five years. But that was under the incentive schemes in force at the time, and the situation has undergone revolutionary changes from several different perspectives in the ten years since then. You are correct that the huge price increases for mains gas, and significantly also mains electricity, means that if you own your property and you're able to install solar panels on it, then it would be insane not to do it.

My solar system was installed by a team of three in approximately a day and a half. This covered everything right from installation of the necessary scaffolding up to generation beginning and me receiving the MCS certificate on day 2. I paid a deposit in advance, and then the balance after I had the MCS certificate.

My solar panels have been in use for approximately 3 years and I have performed no maintenance of any sort.

There is no real concept of "converting to solar power", unless you are on a remote island and planning to go off-grid. Instead, you simply install solar generation capacity and you then use the power generated either to meet your ordinary electricity consumption needs, or potentially for some of your hot water heating or space heating needs. (I do all three.) You then also sell the surplus back to the grid in one way or another. There will still be times when your electricity demand or your heating requirements can't be 100% met by the solar power you generate (even if you have batteries), and at those times you will still import from the electricity grid as normal, or you will use fossil fuel heating sources like a gas boiler for as long as you still have one.

This makes it easier because you don't have to plan your solar panel install around your heating system replacement, instead you plan your solar panel install around whatever you are doing about your roof. So in our case for example I knew that the gas boiler was in poor condition when we purchased the property, we had an electric car in mind for the future, but I went ahead with the largest solar panel install I could manage, and a few years later the gas boiler replacement still hasn't happened and the electric car hasn't yet either. But the solar panels are ready to contribute when they do.

Yes solar panels can generate sufficient electricity for electric vehicle charging. But there will still be times, when generation is low for example, when part or all of your vehicle charging comes in from the grid, with solar generation merely supplementing it. This is seamless, you don't need to worry about it at the time - unless you want to fine tune things with something like a Zappi charger.

EricMears

Hexane said:  Yes solar panels can generate sufficient electricity for electric vehicle charging. But there will still be times, when generation is low for example, when part or all of your vehicle charging comes in from the grid, with solar generation merely supplementing it. This is seamless, you don't need to worry about it at the time - unless you want to fine tune things with something like a Zappi charger.

Although I have solar panels and an EV,  I very rarely charge the car from surplus PV gen.  Mainly because we prefer to use our 'free' energy for cooking lunch or running household appliances but also because it's quite difficult to find steady conditions with enough spare power for the car and that my Octopus Go-faster tariff provides plenty of low cost power overnight to keep battery at a comfortable SOC.

Reed_Richards

If you live in the UK you will not have enough solar power in winter to run a heating system.  Days are too short, more frequently cloudy and the sun is not powerful enough.   

NoobSolar

I would suggest a high efficiency log burner and a friendly tree surgeon to drop off wood you can then chop up with an electric chainsaw and store in a shelter. With solar panels on top. Use the chainsaw during early summer so the electricity for it is free.

While you absolutely cannot heat the house on solar energy in November to March, you should still include an iboost water heater for a large cylinder with two immersions on it as even during those months it will take the edge off your gas costs for heating the hot water. And April to October it will heat pretty much all of your hot water tank.

Golden rule with solar is get as much as you can. So if your house could house a large amount of power, for example 10kw and above, you will find even in the pit of winter there will be some benefit and during the summer you will export lots to offset higher costs in the winter.

Insulate the living bejeezus out of the property. Get a solaredge system with optimisers.

Screwdriva

Now that you know your roof shingles need replacement and you would like Solar PV, GB Sol make excellent solar shingles which may prove more aesthetically pleasing + cost effective. A south facing roof has a <7 year payback period with traditional panels but you'll need to factor in the cost of traditional re-roofing compared to the incremental cost of the solar shingles as well. 

Next, consider if you have the land surface area for a ground source heat pump (higher SCOP than air source heat pumps that most install). 

And finally, if you can, triple glaze and insulate as much as economically feasible. We're at the dawn of a new age where investment in energy savings can have a foreseeable payback period. 

Exiled_Tyke

Hexane said:

Yes solar panels can generate sufficient electricity for electric vehicle charging. But there will still be times, when generation is low for example, when part or all of your vehicle charging comes in from the grid, with solar generation merely supplementing it. This is seamless, you don't need to worry about it at the time - unless you want to fine tune things with something like a Zappi charger.

I reckon it's easy for people to understand that summer is sunnier than winter but those who've no experience of PV systems often don't realise how big that difference is.  Where I am the sun gets to 60 degrees above the horizon in summer but peaks at 13 degrees mid-winter.  The arc of sun mid June is about 270 degrees but mid winter around 90 degrees.  For me this translates to about 20kWh of PV generation during the best days of the year and an average of 1 kWh per day during December and January. And there are plenty of days with no generation at all.      

zeupater

Screwdriva said:

Now that you know your roof shingles need replacement and you would like Solar PV, GB Sol make excellent solar shingles ...

Hi

Alternatively, have a look at reducing material & effort duplication ... it may work out considerably cheaper to install an 'in-roof' solution so that you're not paying for new tiles and then covering them with panels, where normal 'in-roof' solutions (roof=good tiles) result in tiles being discarded ....

You may find a roofing company that will work with a PV installer to reduce material (tiles etc) & access (scaffold) costs, or maybe a PV installer has a stock of good tiles from their previous 'in-roof' installations which can be used to cover the rest of the roof .... definitely worth looking into  ...

HTH - Z ...

Exiled_Tyke

zeupater said:

Screwdriva said:

Now that you know your roof shingles need replacement and you would like Solar PV, GB Sol make excellent solar shingles ...

Hi

Alternatively, have a look at reducing material & effort duplication ... it may work out considerably cheaper to install an 'in-roof' solution so that you're not paying for new tiles and then covering them with panels, where normal 'in-roof' solutions (roof=good tiles) result in tiles being discarded ....

You may find a roofing company that will work with a PV installer to reduce material (tiles etc) & access (scaffold) costs, or maybe a PV installer has a stock of good tiles from their previous 'in-roof' installations which can be used to cover the rest of the roof .... definitely worth looking into  ...

HTH - Z ...

Which got me thinking.  It's a known fact that in-built panels are a little less efficient than the built-on types that most of us have, because the latter get better airflow and hence keep cooler.  However with a new roof and smaller panels/shingles I'm guessing more of the roof can be covered which may more than compensate for the lower efficiency?? 

jimjames

Exiled_Tyke said:

Hexane said:

Yes solar panels can generate sufficient electricity for electric vehicle charging. But there will still be times, when generation is low for example, when part or all of your vehicle charging comes in from the grid, with solar generation merely supplementing it. This is seamless, you don't need to worry about it at the time - unless you want to fine tune things with something like a Zappi charger.

I reckon it's easy for people to understand that summer is sunnier than winter but those who've no experience of PV systems often don't realise how big that difference is.  Where I am the sun gets to 60 degrees above the horizon in summer but peaks at 13 degrees mid-winter.  The arc of sun mid June is about 270 degrees but mid winter around 90 degrees.  For me this translates to about 20kWh of PV generation during the best days of the year and an average of 1 kWh per day during December and January. And there are plenty of days with no generation at all.      

These are the raw numbers for our solar. Very similar to you with 20kWh on best and slightly more in December than you with average of just around 3kWh. When you consider difference in consumption between the times of the year it's even more significant.

http://solar-panels-review.321web.co.uk/index.php/yearly-comparison-of-solar-pv