We’re running a pilot to test installation of rooftop solar PVs and storage batteries with bp Lightsource Labs.
The partnership will also make use of Lightsource Labs’ home energy management technology – Tribe – and cloud-based Virtual Power Plant (VPP) platform to monitor and optimise live energy generation, storage and usage.
Using the systems as part of a VPP means that Pure Planet can aggregate each individual storage system together into a ‘power plant’ and operate them to reduce the cost of supplying electricity and help balance the grid. We think VPPs could play an important part in getting the UK to net zero.
I’m one of five participants taking part in this first phase of the pilot. We’re all part of the Pure Planet team and we’re also the first ‘guinea pigs’ to experience the process. So we’re at the very start of the first phase of a two-year pilot to test the hardware and service needed for our Members to generate and store their own renewable electricity at home.
We’ll be looking to expand it to involve Pure Planet Members soon and if you’re up for helping out, add a reply to this thread announcing the pilot and partnership.
As the scaffolding goes up and the panels are fitted, I thought it might be of interest if I shared my experience of the pre-install questions and preparations. I’ve already had some questions posted in a community shout-out which I’ll attempt to answer here. But if you’ve got any more questions about the pre-installation and installation process, please do add them in the replies below!
I’m planning to write a separate post about using the technology, and the app, and so on. And another one about how to export my energy to the grid, and how it’s affected my energy bills.
Questions I had about solar rooftop PVs and batteries
I guess my first question was…. How does it actually work? Here’s the science!
PV systems use cells to convert sunlight into energy. The PV cell consists of one or two layers of a semi-conducting material, usually silicon. When light shines directly on to the cells, it creates an electric field across the two layers and creates electricity to flow.
The greater the intensity of light, the greater the electricity that is generated. The solar panels gather the electricity and this is then converted from ‘direct current’(DC) electricity to ‘alternating current’ (AC) electricity via an inverter switch.
Once this has been converted, you are ready to use the electricity or export it back to the grid.
How much energy will I get from solar panels?
For the purpose of this pilot, I’m a lucky, lucky boy because basically I’m getting the whole lot for free. A big perk of working at Pure Planet. If I were to pay for the solar panels, battery kit this would cost me somewhere around £8,000 including labour to put up the scaffolding, install the panels, connect it to the battery and connect it to an inverter, to the meter and mains.
Now, £8,000 is not a small amount of money. We had a great question from
When signing up for PVs, you get a ‘proposal’ of predicted system performance. This is based on the size of your roof, how many panels it’ll hold. It’ll be estimates, of course, because the amount generated depends on the weather!
My roof has space for 12 panels. Given the angle of my property, my PVs will be most active in the mornings. My estimated output based on the number of panels is 3.24kWp, or kilowatt ‘peak’.
Estimating the total energy produced for solar panels uses a calculation of 3 factors
- kWp (total size of solar panels installed)
- Kk (predicted amount of sunlight for your postcode)
- SF (predicted amount of shade, which changes depending on month and angle of sun and on elements which might block the sun, such as chimneys.) This diagram is useful to visualise it:
The calculator is kWp x Kk x SF
For me, that works out as 3.24p x 935 x 1
Total: 3,029 kWh per year.
Which is about half of my annual electricity bill!
How much CO2 will I save?
Of course, because I’m on supply with Pure Planet, my energy is already renewable, even if it does get mixed up with dirty fossil fuels on the grid.
With solar PVs at home, there’s 3,029 kWh of pure solar power. On average renewable energy saves 200g of CO2 per kWh, so my home PVs will save just over 605kg of CO2 per year.
Does the power produced change over the years?
This question was asked by
Do the panels need to be maintained?
Good questions from
The hardware itself has few moving parts so won’t need lots of maintenance. But once every 10 years you need to replace the inverter switch which converts DC to AC. They cost about £500.
It’s recommended that you clean your panels now and then.
One thing that is worth mentioning is whether you need bird protection netting. This was an optional extra and it’s suggested that you do get this if you have lots of birds near your home. As we’ve got loads of birds in our garden, including starlings who nest in the roof every year, we decided to pay for this extra, which was £400.
Do they need to be weather proofed, and how do they affect home insurance?
These questions are from
The panels are already weather proofed, and come with a 10 year warranty.
During the installation, who does which bit?
As we got closer to the installation, I then wondered how many different ‘parties’ are involved in this? The answer is four... at the moment.
- Pure Planet, who supply my energy from the grid and who I will also export energy back to
- Coolpower Electrical. The solar PVs retailer and installers. They also sell the battery, inverter and the leads.
- Scaffolders. Will be included in the installation quote and of course depends on how big your home is.
- Lightsource Labs - Run the technology, the ‘Tribe’ box which speaks to the app and shows your how your energy is being generated, used and exported.
Does the weather affect installation? Will rain delay it?
Typical, we had the most amazingly sunny spell just a week before the installations, and then along came the classic British Summer…. And it rained. This didn’t delay things though. I suppose it’s a question of common sense. If there was huge storm with lightning, the installers would probably want to wait for it to pass.
How will my EV work with this new system?
A big question for me, and I’ll do a separate post when I know more. My EV is, essentially, another means of storing energy. I could, I think, charge it up during the day from solar energy, and then empty it by exporting the whole lot to the grid in the evening. And repeat the following day. Of course I’ll need to be certain that I don’t need to actually drive anywhere.
Questions I was asked by the installers
All the pre-install questions were about my property. I was asked to draw an outline my roof over a map, so that Coolpower Electrical was able to get a general idea of which direction the roof faces, and how many panels it can accommodate.
Then I had to send them several photos of my electricity meter and fuse box set up, photos of areas (such as the garage) which could be used to house the battery, which needs a bit of space for heat circulation, and any other info that was relevant, such as my EV charger.
As this ‘ticked the boxes’, the next step was a site visit, so that they could confirm it all, talk me through the process, and also take more photos of the roof/walls for the scaffolders.
All this info was used to form the contract, and there was a final discussion about the bird protection option.
(An aside. Earlier this year I took part in an unrelated Zoom call with a company called Solar Streets which offers bulk discounts if it can sign up 50 or more properties from one town in one hit. They asked me the same questions, and also wanted me to draw my roof on a map, so it feels like this is all quite standard now. )
That’s my little write-up about the solar PV and battery installation process, before and during. I hope it’s useful for anyone wondering about this stuff! Coming soon to a Community near you: How to use the tech; How to do smart export guarantee and send energy I don’t need back to the grid; How does my EV fit in with my home solar and battery set up.