What should I know about solar panels?

OmegaA

I see that solar panel prices are now significantly cheaper than 5 years ago. I am educating myself what installation I should have, what panels etc. Therefore, I have the following questions if you might advice me on:

1. It feels like there are no bad solar panels around at the moment as long as they are new and modern – monocrystalline, 25 years warranty, low deterioration rate (less than 8% in 10-12 years) and the power is typically 315-345 W. So, the difference is mainly aesthetic. What should I pay attention when choosing one panel over other?

2. Probably the key element is inverter – I was told they break more often than anything in the set up and typically won’t last beyond 15 years. And:

     a. I was told that SolarEdge has unique patented design that no other manufacturer can copy – you can monitor what any panel is doing and partial shading of any panel won’t affect others. There is also Enphase microinverter, but I feel this is less reliable because I will have more inverters, thus significantly increasing chances a panel will go wrong. And replacing each broken inverter on the roof is more difficult than on the ground (I assume sensors of SolarEdge attached to panels are too simple and reliable to break). Are my assumptions correct?

    b. It is important to know what each panel is doing – if I have a traditional inverter, then I won’t know how each panel is performing and the overall performance will be affected by the worst panel. Is this true? This is how I understood SolarEdge’s advert, I would prefer validating this statement

3. Battery storage is still ineffective. Yes, Tesla and one another company make good batteries, but they are too expensive and not worth the money. I made quick estimations and feels like it will take me more than 15 years to pay off the battery, so not cost effective. What is your experience?

4. Heating up water with Solar iBoost+ using solar electricity. Is it not cheaper to use gas, and sell surplus electricity to the grid? Or feeding to the grid is too complex and expensive that this is not cost effective? Or feeding in tariff is too low that it is cheaper to use it for heating water?

Thank you

matelodave

The feed in tariff has stopped so the only real benefit of solar panels is that you can use the energy yourself. There is a new system for selling it back to the supplier but they can set what ever price they like - for instance Octopus will pay you 5p/kwh if you are a customer but only 3p if you aren't.
they have to be installed to an approved standard (usually an MCS installer) and the energy company can define what that standard should be and you need an export meter.

You could look at the Green & Ethical threads to see what the general consensus is but IMO if you've got to borrow the money to buy the panels then they are a waste of time coz you'll probably never get your money back so you need to do your own sums to see whether the payback period is worthwhile especially if you cant use all the leccy that you generate - for instance if you are at work all day when the sun shines you wont get a lot of benefit because you cant use your appliances. Conversely in the winter when you use more energy because its colder and the sun doesn't shine then you wont get much benefit either/.

Ectophile

If all modern panels are perfect, why do you need to monitor what each panel is doing?

OmegaA

Ectophile said:

If all modern panels are perfect, why do you need to monitor what each panel is doing?

To be confident all still working properly

matelodave

You might find this a bit more informative - https://www.which.co.uk/news/2020/01/solar-panels-and-renewable-energy-what-are-the-costs-and-rewards-in-2020/ and the Ofgem in on the Smart Export Guarantee which can into force on 1st Jan 2020

OmegaA

Thank you for the feedback
It does sound like I know enough about solar panels, but not much about batteries and my consumption. Would you know some links on internet where I could estimate my consumption around the day? Because I typically leave home in the morning, come back late, so there is little point of having solar panels without a battery. However, the batteries are going through a quick evolution right now that I feel it is too early installing them
Thanks

tim_p

Why not start by taking some meter readings, daily at the same time, to get a handle on your actual consumption. I’ve had panels since 2014 and take regular readings and have a good idea of usage over that period. 

Fly100

I can tell how we did ours ( New Build) however, with a little added investment you could do the same.

We installed a good quality inverter. Some for example some will say they are 4kw but only do 3.6kw. Not a huge drop but over 365 days its a decent amount. Solar Edge was the equipment we used. In 12 months we produced 7.5 MW of electricity.While we are on the last feed in tariff we earn approx £45 a month( averaged over 12 months) However, we bought a add on box that controls the immersion heater. Im unsure if you know but they deem you will use 50% of your produced electricity, so while you get paid 100% for production, you will get paid 50% for the export. ( example produce 500kw generation payment will be for 500kw but export payment will be on 250kw).The box sends all surplus electricity to the immersion heater, we installed a 300L tank. Its well insulated so today's Sun will heat the water and provide us enough water for showers before work and general house stuff. While this may sound amazing, our boiler will not fire from March until October ( we fire it if we have no Sun but count these as a once a month maintenance run).

You need to find ways of using as much of your Solar production as possible. Happy to answer any questions you have.

FLY

Mister_G

Fly100 said:

I can tell how we did ours ( New Build) however, with a little added investment you could do the same.

We installed a good quality inverter. Some for example some will say they are 4kw but only do 3.6kw. Not a huge drop but over 365 days its a decent amount. Solar Edge was the equipment we used. In 12 months we produced 7.5 MW of electricity.While we are on the last feed in tariff we earn approx £45 a month( averaged over 12 months) However, we bought a add on box that controls the immersion heater. Im unsure if you know but they deem you will use 50% of your produced electricity, so while you get paid 100% for production, you will get paid 50% for the export. ( example produce 500kw generation payment will be for 500kw but export payment will be on 250kw).The box sends all surplus electricity to the immersion heater, we installed a 300L tank. Its well insulated so today's Sun will heat the water and provide us enough water for showers before work and general house stuff. While this may sound amazing, our boiler will not fire from March until October ( we fire it if we have no Sun but count these as a once a month maintenance run).

You need to find ways of using as much of your Solar production as possible. Happy to answer any questions you have.

FLY

Gosh, you must live somewhere very sunny!  Our 3kWp installation, South facing on 45 degree roof, only produces 3MW per annum.

Fly100

Mister_G said:

Fly100 said:

I can tell how we did ours ( New Build) however, with a little added investment you could do the same.

We installed a good quality inverter. Some for example some will say they are 4kw but only do 3.6kw. Not a huge drop but over 365 days its a decent amount. Solar Edge was the equipment we used. In 12 months we produced 7.5 MW of electricity.While we are on the last feed in tariff we earn approx £45 a month( averaged over 12 months) However, we bought a add on box that controls the immersion heater. Im unsure if you know but they deem you will use 50% of your produced electricity, so while you get paid 100% for production, you will get paid 50% for the export. ( example produce 500kw generation payment will be for 500kw but export payment will be on 250kw).The box sends all surplus electricity to the immersion heater, we installed a 300L tank. Its well insulated so today's Sun will heat the water and provide us enough water for showers before work and general house stuff. While this may sound amazing, our boiler will not fire from March until October ( we fire it if we have no Sun but count these as a once a month maintenance run).

You need to find ways of using as much of your Solar production as possible. Happy to answer any questions you have.

FLY

Gosh, you must live somewhere very sunny!  Our 3kWp installation, South facing on 45 degree roof, only produces 3MW per annum.

Im in the Uk, 35 degree roof @ 160 degrees. 6Kw of panels on a 5kw inverter.

Mister_G

Ah! that explains it. You'd said about 4kW inverters, so I assumed that's what you had.  Do you get FIT on the whole 5kW or just the max 4kW permitted for FIT?