I just realised I forgot the most important detail before starting. Electricity costs for the year will be roughly £130. To which must be added the onerous £232 standing charge. With energy bills expected to fall later this year, it is possible that the standing charge will be double our electricity costs!!!
Before we launch into the nitty gritty, some random thoughts.
Firstly, I've edited this to clear up one misconception I've heard many a time, that is solar PV panels do not generate electricity in cloudy weather.
Solar PV panels DO generate electricity in cloudy weather, just not as much. To give an example. Tuesday 21st and Wednesday 22nd were extremely cloudy days (10/10 cloud) with torrential rain - witness Rishi Sunak getting soaked announcing the general election date. Our panels generated 4.3 and 6.2 kWh respectively. The 22nd May (cloudy with sunny intervals) our panels generated 19.8 kWh. By Sunday 26th May (sunny with cloudy intervals) it was 27.8 kWh.
We live in Finchampstead north, which is about 2 miles south of Wokingham or about 30 miles west of London. Our house is on the edge of a large housing estate, built in the 1990s. Finchampstead north is basically a whole series of housing estates. The area is a mixture of rich, reasonably affluent and not so affluent.
We had our first set of panels fitted in August 2011. Ours was the only Solar panel installation in our whole estate (including civic buildings) until the energy crisis. This really annoys me. Most of the people on our estate work in the white collar sector e.g. IT, local council officials, surgeons, doctors, civil service, etc. Some also trade (like our neighbours), but they work really, really hard. Most are two income families. Therefore reasonably affluent, with cash to spare. Yet they don't invest in solar panels. They spend their cash on expensive cars, toys, etc.
Until now, that is.
There's a whole rash of them appearing all over the estate. Still in the minority, but increasing in number. The worse offenders, we've found, are the rich. One street we walk along every morning, is stuffed with houses costing in excess of £1 million to £2 million, with driveways crowded with luxury cars. Not one has solar panels.
Sadly, there is a huge amount of ignorance about solar panels and batteries, which even some technical people I've talked to have.
90% luck, 5% field craft, 5% camera skills.
I'll have to provide further background information before launching into our installation.
First and foremost, I would suggest insulating your house before fitting solar panels or, more importantly, a heat pump.
Our house is a modest, four bedroom jobbie, with integral garage i.e. part of the house as opposed to offset to one side. It was built in the 1990s to the usual low standards of British mass house builders.
The roof is east-west facing and, unfortunately, has gables to the front.
The 'double glazing' was a laugh. Wooden frame (warped badly) with 6mm gap between panes. Solid wooden back and front doors (again badly warped) with single pane glazing.
As for the garage. The door had huge gaps in it, allowing wind to whistle through it; sometimes so strongly it would blow the door to utility room open. Freezing in winter, boiling in summer.
Loft insulation was a decent 150mm but over the years had become compacted, with areas of the attic floor exposed by builders who hadn't put the insulation back properly when installing stuff for the previous owners. There was no, repeat no insulation over the gable.
In short, our house was freezing in winter and boiling in summer. Wind whistled in via the warped window frames and the large gaps in the garage door; despite weather stripping.
Fortunately, our house has 75mm cavity wall insulation. Much to my surprise. Our house was built in a transition period where cavity wall and loft insulation requirements were increased.
After saving up for a long time, we/I set about improving the insulation of our house.
These changes made a massive difference to both the quality of our home and our fuel bills. Our house no longer felt freezing in winter. There was this cold zone underneath the gables, due to lack of insulation; it was noticeable when you walked under them. This disappeared after I insulated their bit in the roof. Also, one of the bedrooms was always cold. It was very marked when we walked from landing into this room. This disappeared with the extra 200mm insulation.
One really surprising result of the insulation: it made upstairs cooler in summer! This really surprised me. Previously, on hot days, we would walk into a furnace when we got halfway up the stairs. Now the temperature gradient is much, much gentler, with upstairs being comfortably hot, rather than extreme tropical hot. Downstairs remains cool, which was a relief when temperatures reached 40C last summer. Upstairs was very hot, but not uncomfortably hot.
With all these improvements, we felt it time to look into extra solar panels and battery. Especially as both had fallen in price so much since our original panels were fitted 12 years prior.
I need to have a word about how you can make money from Solar PV panels or wind/water turbines. This is money you earn from any excess electricity you have after either consuming it yourself or filling a battery.
Any house with Solar PV panels and/or wind/water turbine is a microgeneration unit. Yep, you are a mini power station, and are treated as such. You'll need either a G98 (less that 3.68 kWp) or G99 ( more than 3.68 kWp) certificate.
The three tariff where you can/could earn money are
Export Tariff
This has been going for as long as I can remember. It is pretty measly - currently 4.8p per kWh exported to the grid. It does, however, keep ticking over nicely. Every installation qualifies for this tariff - provided they do not have the SEG.
Secure Export Guarantee (SEG)
This tariff was brought in when the Feed in Tariff was abolished. They amount paid is at the discretion of the energy suppliers. It can be zero. Luckily it is a lot more. Standard SEG tends to be between 15p and 16p per kWh exported to the grid. EON Next will pay 40p per kWh, but with conditions e.g. you have to be with EON Next and bought/installed panels via them.
Feed in Tariff.
This was abolished a couple of years ago. It was designed for pioneers/early adopters of micro generation facilities. Solar panels in our case. It is index linked and lasts for 25 years. But we took the risk of installing solar panels.
As we got the FiT, we do not qualify for the SEG; it's the rules. We also had to keep our two sets of panels separate (i.e. each has their own generation meter), but they are joined together prior to feeding into our battery.
EVs present a little bit of a challenge when deciding how to charge them. Energy suppliers (e.g. Octopus, EON Next) do offer rather cheap charging rates, typically 7p or 8p per kWh, when you charge your cars in the wee hours of the morning. Therefore, between May and October, when your solar panels are generating and exporting huge amounts of energy, does it make sense to charge your car with electricity that is earning you 16p per kWh or does it make sense to export the electricity and charge your car overnight paying 8p per kWh?
Oh, one final point about EVs. If your EV charger is two way V2G (vehicle to Grid) then you can make your car a stand by battery for the grid and charge your car battery for free!!! There are conditions, of course. One being that your car has to be available to discharge to the grid at peak hours - I think 16:00 to 19:00. Check out Octopus energy.
OK. Now on to our system or systems.
We had a 2.4 kWh solar power system fitted in August 2011. Ten panels, inverter, scaffolding and installation cost £8,800 including (I believe) VAT. No battery as they cost an absolute fortune back then.
The panels are on our east (rear) facing roof. Unfortunately, we have a large hill, crowned with large trees about 400 yards from the panels, plus our large oak tree at bottom of short garden. This prevents generation for about 45 minutes in the morning.
The system has worked well, and paid itself off in less than six years via a combination of reduced electricity costs and earnings from both the Feed in Tariff and Export Tariff.
An equivalent system today, will require six panels and can cost less than £5,000 fully installed. Pay back time, if your are obsessed with this, should be about six years via reduced electricity bills (prices are much higher than previous years) and earnings from the SEG.
I have spent 13 years quite frustrated at the amount of electricity we exported, as we didn't have a battery. This frustration only increased during the cost of energy crisis. I also noticed that our west facing (front) roof received sun until quite late at night, despite the houses and trees opposite.
Solar panel, inverter and battery prices (in particular) have dropped dramatically to a point where we decided to bite the bullet and get panels on the front of the house, with a battery. We also went for an EV charger, even though we don't have an EV. Future proofing. Plus visiting sprogs and friends can use it if they have EVs.
Our spanking new system consists of nine 340 watt panels, with a 5 kWh Alpha ESS Smile-B3-plus battery/controller/wi-fi dongle, and Zappi EV car charger. Total cost, including scaffolding, inverter, AC coupler, installation, admin around G99 and MCS documentation came to £10,300. We didn't pick the cheapest of installers, as we didn't quite trust the others - bad reviews, they had.
Some of you might wonder why our installer didn't specify a bigger battery or why we didn't ask for a bigger battery?
Simple. When you need power from the battery (i.e. during winter) there isn't enough sun to fully charge it. When there is enough sun to charge the battery fully, you tend to use less electricity and therefore do not need extra battery capacity.
That has been the case with us. During December and most of January, our battery did not get charged fully. I was, however, very surprised how much charge we did manage to get and how much we spent off gird (i.e. running on battery) during the horrible months of December, January and February. By end of Jan and February we manage 24, 48 even 60 hours off grid.
We have been 'OFF GRID' since 14th March 2024. I hope to stay 'OFF GRID' until early October 2024.
Note; It is not possible to be totally off grid with solar panels and battery. The battery controller has to work out where to supply electricity from. Thus does it supply electricity from
The battery controller doesn't get the calculation 100% correct - particularly where electric motors are concerned. It manages between 5 and 10% of electricity demand. Thus, currently we are drawing about 200-400 watts from the grid per day. This is mostly taken up by the hard to estimate loads of engines in fridge/freezers (compressor), condensing boiler (motor in boiler and pump in Central Heating system), and my old lady when she uses her hair dryer.
Also, I've read that Smart Meters poll your electricity demand every 6 seconds. Our Alpha ESS controller polls electricity demand every 10 seconds. Already there is a discrepancy.
Panels are panels, so I wont include photos of what they look like. But this is what the complete system in the garage, old and new, looks like, and surrounded by normal garage junk. Images of this are rarely seen.
Our neighbour has their battery on the outside wall. At first I thought it was because it was for safety. Then I remembered - they don't have a garage!
Now the interesting stuff - statistics!
This first chart shows running totals since 21st December 2023 when our new system went live.
The red line shows how much our electricity would have cost us without any panels or battery. This does NOT include the onerous and controversial standing charge.
That is reserved for the yellow line. Note how the line steepens at the end of March. That's because the swines increased the standing charge by over 25%
The blue line is how much we actually paid for electricity. Notice how it's practically flat since March 14th. In fact we would have been off grid since the start of March were it not for that rather nasty storm that came through.
The green line is how much we've earned exporting electricity to the grid. Note, this is at the measly Export Tariff rate of 4.8p per kWh. It would be much higher had we qualified for the SEG.
The chart below shows daily costs and earnings. Unfortunately, I've had to use an old chart as something strange has happened on google charts. It's lost a data series for some reason.
Once again, the red line is daily electricity costs had we not got solar panels or battery.
The blue line is daily electricity costs with solar panels and battery. Unsurprisingly it can be similar to the red line during the winter months. Christmas day and December 27th were two memorable days when 400 W and 100 W were generated respectively.
However, as you get into mid to late January and then February, you'll begin to notice that we are spending more and more time off gird. This is where the blue line gets close to the x-axis. By the beginning of March we are pretty much off grid, were it not for a couple of named storms hitting the UK.
The yellow line is the onerous standing charge, relentlessly costing us every day regardless of our electricity consumption or generation. It actually encourages people to use more electricity not less.
The green line is how much we earn per day exporting electricity to the grid. Remember, this is the Export Tariff rate of 4.8p per kWh, rather than the more natty 15p - 40p per kWh of the SEG, which new installations will qualify for.
I can't show our FiT earnings as our old systems doesn't supply data I need.
I'll replace this graph with one more up to date, once I figure what google charts is playing at. Graph replaced. Google charts is still rather buggy.
This final chart shows how much electricity we generated per day since 21st December 2023. The variability in sunshine is astonishing. You can easily see the storm that passed over the UK last week. Also the nasty storm on 13th March that stopped us being off grid since 1st March.
One final note for now. Having solar panels and battery can modify your energy usage. Using the dashboard below, and looking out of window to see the weather conditions means we can decide whether to rush around using appliances. Thus, we'll do mega roasts or bakes, sweep round with vacuum cleaner, etc to use the free electricity being generated by our panels.
With the central heating switched off, we can use an electric fire to boost the temperature of individual rooms using the free electricity from our panels.
This not only reduces our gas bills, it also reduces our carbon footprint, and hopefully does a tiny bit to save the planet.
The battery controller (as do they all) comes with a rather nice dashboard. Data is loaded onto Alpha's cloud system, and I can log on and see it any where: I have the dashboard on my laptop, an Android tablet and my mobile. I monitor it often. Again, this is an old image. Our CO2 footprint is now reduced by 1.3 tonnes.
Hope you found this useful. I may add more.
One final note. To make best use of any solar panel and battery system, it is best to have a Smart meter installed. I believe you need one to take advantage of some of the energy saving tariffs offered by energy companies.
I forgot to add.
In retrospect, I think it would have been a good idea to replace our old boiler with a heat pump rather than a condensing boiler. Running costs of the heat pump would have been reduced with the extra electricity we generated. Also, the newer heat pumps can heat water to a higher temperature, more like the 60-65C of our condensing boiler.
As usual with the British weather, when you need the sun most to generate electricity, we get hardly any - sigh.
Interestingly, our neighbours have just installed an air-to-air heat pump; basically an air conditioning unit that uses heat pump technology (compressor) to heat air, which is fed into the house. It has the added advantage that it can cool air during summer - effectively for free.
Although I was very interested in it, I elected not to get one installed as it doesn't qualify for the government £7,500 grant.
Another add on you can get is a unit that will instruct an immersion heater to heat water in a cylinder when there is free power. I was rather interested in this, though again it is only really worth while between March and October, when there is lots of excess sun. Unfortunately, this will take a very long time to pay back. We would have to pay for the unit plus an immersion heater, plus the Memsahib and I do lots of sports, and can shower at sports centres, therefore our water usage is very low.