Egg and their system? Any good?

[TheMitchells]

I have just had an estimate from Egg for a solar array and, they suggest 12 No. 390W Trina Solar all-black panel with Tesla Powerwall.  this whole area is completely bamboozling to me so advice would be great. 

 
Their estimate for the supply and installation of the solar PV system is £8,900 and £9,250  for the supply and installation of the Tesla Powerwall. Should we wish to install a battery at an alternate time then VAT rate is 20%. 

Basically, it is a small bungalow with a south facing (no shade) roof in which my elderly parents live.  They have an old large 'box' in a cupboard which heats up at night and then blows warm air around during the day.  there are also 2 electic night storage heaters, one in the lounge and one in the lobby. Plus an electric fire for extra heat - mainly in winter when the storage usits have ran out.  They do like to keep the place warm and average electricity costs are currently £120 a month as they are on a fixed deal till Dec 23 - phew.  they use 2400kW on the day rate (24.1p per kW) and 9000kW at night (9.19p).  it is 35.6p per day standing charge.  So based on last years use, their bills this year should be about £1,425.16.   daytime costs are the usual white goods and little else.  They have an electric shower but that is only once a week. 

 

it is a strange system in that the storage heaters are all on a separate ring and only come on at night.  Everything else is on the day ring and even if put on at night, add to the daytime bill. 

 

I am worried that their bills will shoot up when they finish their fixed rate and also it seems an ideal roof for photovoltaics as there is no shade and it faces almost directly south. 

 

When my parents no longer need the place, we shall re-vamp the whole place, extending the kitchen and probaby install a new heating system, as this one is so old (probably the origional from the 70's). 

 

so - does the proposed system sound good?  And would a Powerwall be a good investment?  or should we wait and do it all when the re-vamp is done.  But that could be severals years away and electricity prices are not likely to come down.  There is no gas to the property although it is in the road outside.

 

Hoping for some help/advice/thoughts as I don't know what to do for the best. 🤪

thanks.

 

 

 

From their email -

We have been installing solar panels for over 10 years, we are an award-winning company our latest aware was for Solar and Battery installer of the Year 2021, so you know you are getting reputable company when you choose us.
 
The panels we install are Trina Solar they are a Tier-1 panel manufacturer; the 390W panels which we most commonly use.  They are all black, high efficiency, low profile panels and come with a 15-year product warranty and a 25-year performance warranty. The way we size a solar PV system is to look at available roof space to start with but more importantly, we look at the existing and potential future energy consumption. 
 
SolarEdge is the only inverter solution we recommend and install because every roof will benefit from an improved annual performance compared to a standard ‘string’ inverter. This system also gives you per-panel visibility of generation, enabling you (or us) to see how the system is performing and highlight any potential issues if any arise in the future.  Although there may be potential no shading on the roof, you will still benefit from a SolarEdge optimised inverter solution. At different times of the day, there will be different light levels (irradiation) on each part of your roof, depending on the position of the sun in the sky (even if the sun is not visible). 
 
The Powerwall represents the best value for money per kWh when you consider the storage capacity of 13.5kWh and a built-in inverter which can do a continuous 5kW charge/discharge, along with grid backup and off-peak charging capabilities. The off-peak grid charging is particularly useful for the winter months when it’s likely that your solar generation would not meet your daily household consumption. With the addition of a Tesla Powerwall to the system, we would expect solar self-consumption to increase from 50% to around 80%/90%, thus increasing your overall energy savings.

[Conor]

Insualtion?

[Thorfun]

solar pv price seems a bit high. we paid around £10k for a 10.5kWp array (28 x 375W LG  NeonH Black modules) with GSE trays, Solaredge optimisers on each panel and a 10kW Solaredge inverter! including installation.

[JohnMo]

Two things worth looking into.

 

Separate ring is normal for storage heating as they are supplied via the E7 part of the electrical system.  The rest of the may not be.

 

1. PV produces the best part of nothing during the heating season, so would not offset the heating costs, even slightly.  What is produced in winter will just be self consumed. 

2. In winter they will be charging up the storage heaters and charging the battery via E7.

 

Quick calc they are spending over £800 on heating.  I would be tempted to give the storage heaters a bit of an overhaul and good clean out.  Review, improve the insulation situation and fix the drafts.

 

[TheMitchells]

40 minutes ago, Thorfun said:

solar pv price seems a bit high. we paid around £10k for a 10.5kWp array (28 x 375W LG  NeonH Black modules) with GSE trays, Solaredge optimisers on each panel and a 10kW Solaredge inverter! including installation.

who was that with, please?

[TheMitchells]

54 minutes ago, Conor said:

Insualtion?

usual cavity wall insulation and lots in the attic.  windows are fairly recent but before us so no idea of how well they are sealed.

[Thorfun]

8 minutes ago, TheMitchells said:

who was that with, please?

I chose Enhabit to do my Solar PV, ASHP and MVHR. they got taken over by/merged with Green Building Store who no longer (at the time of writing) offer Solar PV and ASHP down in the south east and so Enhabit refunded me for work not undertaken and sent me on my merry way to find someone else to finish off that work. 

 

our MVHR was taken over by GBS and they're currently installing that.

 

due to the above I can no longer recommend Enhabit but it might be worth giving GBS a call to see if they cover your area.

[Caddy]

Bit late on this but I had the 9 of the same panels (390W Trina) fitted with Growatt Inverter for £5200. The panels are around £100 each so £8900 seems expensive to me.