Solar panels

GibbsRule_No3.

I have been lucky and my HA have installed a new roof with Solar panels. It has an inverter but no batteries but I don’t actually understand how they work, we have had no instructions and the person who liaises with is not up to speed.  I can see the meter is registering the KWs so the sunny days this week are doing their job but how do I use it?  Will the meter go down when I use the power instead of the normal metered usage or does it just show the total generated?  As there are no batteries when does the solar power stop being of use?  I don’t have a smart meter yet and mention was that to sell unused back to the grid one would be needed.

[Deleted User]

The output of your panels will vary depending on the time of the year; the amount of sun/light; outside temperature etc. 

If your panels are outputting 1kW of power and you put the kettle on, then the remaining 2kW will come from the Grid. Conversely, if your panels are outputting 3kW and your house load is 1kW, then 2kW will be exported to the Grid.

Put simply, if you want to get the most out of your panels then use the energy when the sun shines.

When solar is being exported, your import meter reading does not go down. If it does, then this needs to be reported to your energy supplier. You can get payments for the solar that you export via the Special Export Guarantee Scheme. You will need to agree to a smart meter. Your energy supplier will then apply for an export MPAN (one meter: two MPANs) and once set up you can claim SEG payments. These vary depending on the supplier and export tariff. For example, Octopus offers 7.5p/kWh for each export unit.

QrizB

GibbsRule_No3. said:

I have been lucky and my HA have installed a new roof with Solar panels.

Congratulations to you and your HA.

I don’t actually understand how they work, we have had no instructions and the person who liaises with is not up to speed.  I can see the meter is registering the KWs so the sunny days this week are doing their job but how do I use it?

The panels on your roof generate electricity when the sun shines. This is converted into mains voltage AC by the inverter and travels from there, via the generation meter, to your consumer unit.

Once it gets to your consumer unit, it will replace the electricity that your home is using from the grid. If you are using more grid electricity than the panels are generating then the extra demand will still come from the grid. If, however, you are using less then the panels generate, the evtra will go out through your meter to the grid and be used by the reat of the country (most likely, your close neighbours).

Examples:

Imagine your solar panels are generating 2kW and your house is using 1kW. The 1kW that your house uses will come entirely from youre solar panels and you won't be buying any electricity from the grid. The extra 1kW will go out to the grid and join all the other electricity available for use on your street.

Now imagine you turn on the kettle, an extra 3kW. Your household demand is now 4kW. You will use 2kW from the solar panels but will have to draw the extra 2kW from the grid. Once your kettle boils and switches off, yuor house will go back to using 1kW and this will all be met by your solar panels.

Will the meter go down when I use the power instead of the normal metered usage or does it just show the total generated? 

The generation meter records all the electricity that the system generates. It will only ever count "up". Your normal electricity meter will measure less when the solar panels are generating, and may even stop completely for most of the day, but should never run backwards (if it does you'll have to tell your energy company and they will replace it with a new one).

As there are no batteries when does the solar power stop being of use?

You will only get power ind daylight. You'll get most when it's a bright sunny day but you will still get some generation through clouds (there may be the occasional very dull winter day when you don't get any power from the panels at all, but those are rare). You might get a little bit of power a few minutes before sunrise and after sunset, depending on the weather.

I don’t have a smart meter yet and mention was that to sell unused back to the grid one would be needed.

A smart meter includes an export meter - a separate register that measures the amount of electricity flowing from your house back out to the grid. If you have one of these you can register with your supplier for "Smart Export Guarantee" - SEG - payments. Some suppliers pay quite well, others pay poorly. Who s your current supplier?

Edit: Dolor has said much the same, but has been more concise about it

GibbsRule_No3.

Thank you for the replies.  So do I assume I cannot actually tell how much the solar panels are giving me?  I have been taking pictures of the SP meter and the ordinary meter so can see how much both the E7 and day meter is using and that the SP meter has 29kW generated since Tuesday.  I suppose battery installation would have been too expensive but would have been cheaper for me the user?

QrizB

GibbsRule_No3. said:

Thank you for the replies.  So do I assume I cannot actually tell how much the solar panels are giving me?  I have been taking pictures of the SP meter and the ordinary meter so can see how much both the E7 and day meter is using and that the SP meter has 29kW generated since Tuesday.  I suppose battery installation would have been too expensive but would have been cheaper for me the user?

If the SP meter says they have generated 29kWh, that's a good sign.

Do you know what your typical daily (daytime rate) electricity consumption was before installation? How does that compare with your daily use since? Hopefully your use since installation will be somewhat less than your use before!

QrizB

One more thing, sorry.

Are you still with EDF? Their SEG rate is dismal, 1.5p/kWh. Your 29kWh would only be worth 43p.

Currently the best SEG is with Octopus, 7.5p/kWh fixed, where your 29kWh would be worth £2.17 (there's also a variable option which is currently paying more). However Octopus's E7 rates are different to EDF's (Octopus has cheaper day rate than EDF, EDF cheaper night rate than Octopus) so it will take a bit of calculation to work out whether switching is worthwhile.

markin

This site will give a general idea of best production times. https://www.solar.sheffield.ac.uk/pvlive/

But see if the is a way to connect to the inverter with an app?

And early morning or on poor days for sun an 800 watt or less travel kettle will take longer to boil but is less likely to pull power from the Grid.

gefnew

Stick an owl Electricity monitor or similar on the pv side then you will have visual display of how much is being generated.
Then you could time shift the heavy loads when you have enough spare power.
Something like this.
 Owl Wireless Energy Electricity Monitor - Energy Usage Meter - For home or work | eBay

Reed_Richards

The way to make best use of your solar panels is to run any appliance that heats (or uses enough power that it gets hot) when the sun is shining from roughly the direction your solar panels face.  Washing machine, dishwasher, electric oven or hob, microwave, vacuum cleaner (if it's a plug-type), electric lawnmower are all examples I can think of.  If you have a hot water cylinder with an immersion heater it might make sense to run that, even if you don't normally use it.       

markin

Reed_Richards said:

The way to make best use of your solar panels is to run any appliance that heats (or uses enough power that it gets hot) when the sun is shining from roughly the direction your solar panels face.  Washing machine, dishwasher, electric oven or hob, microwave, vacuum cleaner (if it's a plug-type), electric lawnmower are all examples I can think of.  If you have a hot water cylinder with an immersion heater it might make sense to run that, even if you don't normally use it.       

Not all at once though, in sequence so not to pull from the Grid, Or 2 at a time if you know the peak wattage is under the solar production.

Benny2020

I have had my panels almost 7 years now and although i have a Geo display that shows current output i can just look at the sky now and think, that's a 1.2 kw sky right there and be pretty close.