Solar panels - are they worth it?

pinnks

I agree with those taking a reasonable and neutral approach here.

It is true to say that the maths doesn't pan out so easily since the FiT was withdrawn but you will save perhaps £150 to £200 per year on leccy bills (possibly a little more if your base load is quite high with things like a ASHP) and you will also become more energy aware (aka geeky) once you have panels and will look at more ways to save energy generally.

In terms of repairs etc i guess it depends on your appetite for risk. As others have said the system is prettu maintenance-free - the panels just sit there with no moving parts and the inverter will run until it breaks just like any other electronic device. The panels self-clean, though I have given mine a wash once when I was up the ladder doing upstairs windows. Whether it was worth the effort is moot.

So, can you afford it, do you want to do your bit for the environment and are you content with a plus/minus nil return on your investment over the next decade or so? A personal decision but a few quotes from local installers and further discussion of those and other issues/concerns you may have on this forum may help you decide.:beer:

JKenH

I have just done some sums covering a full year of solar for my 7.8 kwp East/West system with Solar IBoost which was installed last summer. Initially the system was installed with a 3kw battery but as this was pretty ineffective this was removed about a year ago and the figures exclude any saving from the battery. I also initially had a meter which ran backwards but this was replaced just over a year ago and so the benefit from that is also excluded.

My inverters had to be replaced in October as they kept tripping out and this cost us some PV generation when we were away on holiday so I am pretty sure on a full year uninterrupted generation we would meet the PVGIS v5 estimate of 6000kwh pa for the system against the actual recorded for the past 12 months of 5940 kwh.

A couple of other changes occurred with 2 ASHPs being added in the spring which will have increased consumption slightly. I also in late spring had the wiring altered to the IBoost so it now heats two separate hot water tanks. (Previously one had been heated by oil after the immersion heater controller failed). The effect of that will be to increase my consumption this coming winter.

I have not taken into account the saving on oil as a result of the switch to ASHPs and the second immersion heater as it is not metered but apart from 3 days CH in May and 1 hour service running the boiler in August I have not had to use any oil over the summer. Last summer the boiler was on everyday for hot water. I am hoping the saving will be in the region of 20% of my £1000pa oil bill but as I said I haven’t included this in the figures as in part this comes from running the ASHPs for heating not pure PV saving.

On that point, I should point out that over the last year I have changed my habits to optimise the use of solar PV when it is available and minimise electricity use when it isn’t. We do cook by electricity as we don’t have gas and this accounts for our usage being so high.

We do have E7 for hot water and the E7 consumption both pre and post solar works out at one third of the total usage from the grid.

The figures

Previous 2 years average grid consumption 6900 kwh per year average
Post PV grid consumption 3419 kwh pa

Solar PV installation and IBoost cost £7162.
Average electricity purchase for preceding 2 years based on current tariff £974.59 pa.
Electricity purchased 18 Sept 2018 to 18 Sept 2019 £520.59
Saving on electricity purchased from the grid £454
FIT and export payments £404.50 (current tariff rates for Apr-Jun 2018 installation)
Total benefit £858.50
Payback period 8.34 years
Payback without FiT/export would be 15.77 years.
With no FiT but assumed 50% export under SEG type scheme revenue would be £159.78 which combined with electricity savings would produce a total benefit £613.78 pa and payback in 11.67 years.

thomas_nichol

Should I go Fixed or Agile for unit price back from octopus energy for PV panels on my roof?. Outgoing Fixed guarantees 5.5p per kWh for every unit you export. Outgoing Agile matches your half-hourly prices with day-ahead wholesale rates- pretty Inexperienced in all this

NigeWick

thomas_nichol said:

Should I go Fixed or Agile for unit price back from octopus energy for PV panels on my roof?. Outgoing Fixed guarantees 5.5p per kWh for every unit you export. Outgoing Agile matches your half-hourly prices with day-ahead wholesale rates- pretty Inexperienced in all this

Agile is V expensive between 16:00 and 19:00. Unless you can guarantee not using the grid during those times, I would not have it.  How much will your system be producing between autumn and spring? I've got a Tesla PW2 battery so I can avoid using any grid for those three hours. It's 19.74 to 23.29p per kWh between those times today.