Solar Power

How it works

The power produced by the solar panels is fed to an invertor - converts from DC to AC that (in our case) firstly feeds the house. Secondly it charges the battery system and finally, it feeds excess energy to the national grid. - Simples!

The process - stage 1

It all started over 3 years ago when I thought I would take a look at whether it would be worth our while going down the solar route. I knew the 'green' benefits but would it work out financially?

Having done my research on the do's and don'ts it was time to find a reliable company. I added two of the largest suppliers/installers in the UK onto the list and, due to my desire to try and keep work local, looked for one in our area. I gave them all the same brief and, considering we were still in the grip of COVID I was surprised that the two large firms wanted to send an employee round to discuss the options. This they did and it was amazing how their sales pitches were almost identical! However, due to their obvious lack of knowledge about the subject and their desire to hit their quarterly targets I gave them a good ignoring. I also spent a dismal hour looking for real life reviews of both and was by this time not surprised that there were huge numbers of disatisfied customers.

Before contacting the local (Cheltenham) company I did research into them and was amazed that all reviews spoke of their knowledge and professionalism. So, phone them I did.

What a difference! Up front acknowledgement that if possible they would do their initial assessment remotely due to prevailing rules, of which I was a little dubious. However. by use of satellite technology they were able to see our house, check its orientation, and calculate its roof size. I just had to confirm the roof angle and then supply them with our annual electricity usage. I have to admit here that, probably due to having 2 servers, 2 freezers, 1 fridge and 1 wine cooler permanentely running plus the usual plethora of TVs, chargers, cooking etc. our consumption is in the high domestic range.

It took 24 hours for them to make the calculations, which took into account equipment degredation over time, and supply me with a full quote that included estimates of annual savings. This information was supplied in spreadsheed form and showed that it would take approximately 17 years to cover the cost of purchase and installation, based on which we decided not to proceed.

The process - stage 2

For those of you who remember 2021, late spring of that year saw electricity prices start to rise, so much so that in October I revisited the spreadsheet supplied, applied the then current average cost per kWh, and discovered that payback had dropped to under 12 years. When, in December, electricity costs were still rising and payback had dropped to circa 10 years we contacted the company and asked them to re-quote.

A quick check of their original quote elicited the reply that the prices were unchanged! The only things that had changed were a) that the solar panels had been upgraded and now produced an additional 40 watts - more power for the same money!!, and, b) there would be a delay in installation due to the amount of work they were now undertaking. We immediately placed our order.

Our installation date was set for April which was a little disappointing but as it turned out was to our advantage. This was due to the then chancellor's decision to cut VAT on solar panels, which put us in the position of more power for less money!! 3 days prior to installation the scaffolding was erected (a company from Bishops Cleeve) and on the expected day 2 vans appeared containing 16 solar panels, 1 invertor, 2 installers, and only 1 battery. It was explained that due to issues in China their supplier had not received the ordered number of slave batteries. However, as soon as they were received the additional battery would be installed.

At the time of ordering the system our electricity was being billed by Bulb but (before they went into special measures) we had already decided that we would move to Octopus energy. Bearing in mind that by this time all power companies were effectively charging the same this choice was based on two reasons. The first was that Octopus were the Which recommended company and the second was their method of repayment for electricity passed to the grid.

The 'feed in tariff' was scrapped a few years ago but all major electricity companies were told they had to provide re-imbursment of domestic supplied energy to the national grid. Of the main suppliers, current rates range from 3p/kWh (EDF.Eon) to 12p/kWh (Scottish Power). However, Octopus have their Agile scheme where rates are between 0p and 35p per kWh. The rate is published for 30 minute periods during a day and gives a significantly higher return than the flat rate systems of the others.

Anyone who has already looked at solar power will know that if you go down the Tesla route they offer a rate of 24-26p per kWh. However, the Octopus Outgoing tariff does not require a Powerwall 2 solar battery which currently cost around £9,000 to install. The Powerwall 2 battery also has a 10-year warranty and will need replacing midway through your solar panel’s lifespan – negating the benefits of the higher paying tariff.

If you use a reputable company all liaison and paperwork with bodies like Western Power (they have to sign-off on the system being used and the expected output to the grid) and unless this is all in order you will not be able to receive payment for your excess electricity. YOU HAVE BEEN WARNED.

Niggles - there always are!

Although extremely professional in anything to do with the actual system the company's admin is not of the highest quality. In particular they are not very good in keeping you informed of issue resolution - they do it, just don't keep you up to date on the progression.

The paperwork. Western Power (don't know about other electricity providers) can take a long time to sign-off on the design and this is needed before a reputable company will commence installation. Also, a similar issue is encountered following installation as they have to verify that all paperwork concerning installation (MCS/Flexi-Orb certified) is correct before you can approach an energy supplier.

The Figures

The data for 2024 has now been used and this comes from our Electricity supplier and our solar system. Where the same data is supplied by both then, in the case of discrepancies, I have used that supplied by Octopus (as that is where the money goes!!)

• Octopus Energy - Import/Export
  • amount supplied in Kwh
  • cost per Kwh that month
  • payment for what we supplied to them*
• Solax systems - Storage and Usage
  • amount generated (not used in these calculations)
  • amount stored/used by the house
  • amount exported to the grid
The methodology used for each month's data is:

1. Multiply the Kwh from Solax to the home by that month's cost/Kwh
2. Compare amount from Grid shown by Octopus and Solax**
3. Verify Octopus figures - multiply Kwh by cost/Kwh
4. Add amount received from Octopus for power exported/

* Octopus use a system which offers changing rates every half-hour, depending on the price of energy at the time. Which means that if you’re on the ball, you can take advantage of amazing rates and programme your battery to import energy or discharge accordingly.
** Octopus do vary slightly from those shown by Solax in which case I use those from Octopus.

The calculations

Month	System to Home	Grid to Home	Grid Payment	Grid Cost/Kwh
Jan	£40.52	£111.46	£1.84	26.78p
Feb	£54.50	£79.99	£0.83	26.78p
Mar	£86.87	£43.41	£13.87	26.78p
Apr	£100.13	£29.35	£24.77	22.70p
May	£97.41	£8.51	£27.63	22.70p
Jun	£94.32	£0.84	£37.83	22.70p
Jul	£89.10	£5.37	£28.46	20.65p
Aug	£85.31	£6.75	£23.69	20.65p
Sep	£64.24	£29.67	£49.37	20.65p
Oct	£55.34	£55.09	£6.97	22.70p
Nov	£32.12	£87.19	£0.74	22.70p
Dec	£21.86	£98.22	£0.05	22.70p
Totals	£821.72	£555.87	£216.05

Bottom line.

Anyone wanting details of the company used please contact us Here.

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