When we had our house built twenty years ago we wanted solar panels, but the extra cost was just too much then. Now they seem much more popular are prices drop. As we have the funds now I looked into it again. We get our electricity and gas from Octopus Energy who are very into renewables and they offered a package that looked attractive. They could install panels and a battery that could supply most of the electricity we need whilst paying us for what we feed to the grid.
It has all taken longer than expected though. We had a surveyor come to check out the house. We had hoped that the battery could go in the utility room, but it needs a fair bit of space, so he said it could go outside. He had some concerns as it needs to be off the ground and with our house being timber frame it would need some sturdy mounting to hang it off the wall. It was also suggested that we upgrade to twenty panels rather than the original fourteen as we have a big roof and that could pay for itself quicker. Before Christmas the scaffolding was put up and a team arrived to do the install. They decided that it was not viable to hang the battery on the wall and we would need to make a platform for it, so they went and the scaffolding was taken down.
We were given a new date in May as they seem to be busy. I bought a load of concrete and we built the platform. This is mainly to avoid the battery sitting in water if it should flood, but that is fairly unlikely anyway. A new install date popped up in February, so we told them to go ahead.
This time it all went fairly smoothly, but there were some hitches. Firstly the wrong fixings for the panel were sent, so the panels could not go up. Then the weather was not great. Working on a roof in rain and wind is not safe and they ended up taking an extra day, but it is all done now.
They did a neat job with the battery and inverter attached to some marine plywood that was screwed to the wall. The cable from the panels goes into the attic for a short stretch and then down the wall in some conduit. There are various switches to isolate things with warning stickers saying some will be live in daylight. We are just putting up a small shed over these units. They are weatherproof, but I would rather they were covered to provide extra protection and also to keep them out of sight.
As soon as things were all connected up we started generating power. Modern panels are fairly efficient and we get something even when it is cloudy. The panels are on the west side, so we get less in the morning before the sun can hit them directly, but it can be enough to power the house.
We have 8kW of panels, a 5kW inverter and a 9.5kWh battery. The latter are from GivEnergy. They have an app that lets me monitor things. On a sunny morning we are charging up the battery and not drawing anything from the grid. A full battery can last us all day. There is also a web dashboard that provides even more data. You can configure it to charge the battery from the grid or feed out at specific times. We get cheaper electricity at night, so I can use that to top up the battery if it gets low so that we have enough power until the sun comes out.
GivEnergy have an API so you can extract the data yourself. I will be looking at doing some scripts for that so that I can generate some charts.
We also got an electric car this year. That is an MG4 which can do 270 miles on a charge. Obviously that will need a lot of electricity and so we do need to draw from the grid for that, but we can use solar for some of it. I will do a report on the car soon, but as our son is the main user I have not driven it much. I recommend checking out 
I expect some people will wonder if all this makes financial sense. Octopus estimate that our system will pay for itself in eleven years. That will depend on various factors of course. Energy prices have gone up a lot in the last few years. Our tariff charges 31p/kWh, but we get four hours at 9p/kWh each night to charge the car and house battery. There is also a 41p/day standing charge. They are sorting our the feed-in tariff that will give us 8p/kWh. We could already be earning from that and apart from the car we do not really need the grid power for the house. In summer I expect the battery to get fully charged in a couple of hours and we could be feeding several kilowatts to the grid for the rest of the day. What we get from that could cover the cost of charging up the car most of the time. It will be tricky to directly compare with our previous usage as we did not have the car before.
I will be looking to optimise our usage. When we have surplus power I can use it to heat our water rather than using gas. I will need to get an automated switch to control that. I played with Home Assistant previous and will probably use it again for this. Of course I will be posting about that.
It is very satisfying to be getting free power. I can try to answer any questions you may have.
Shine on!
