Farncombe Community Garden
Take a look at the commercial solar PV installation we completed for the Farncombe Community Garden in Godalming.
This solar-only installation was designed to maximise the green energy production of the site, helping this community garden reduce its energy bills and earn from the excess green energy it can export!
Their Solar PV System
This is an overview of the Solar PV system we installed for this Community Garden.
Farncombe community garden has one main building on which we installed 18 x JA Solar 460W monofacial all-black panels. The south-facing roof is ideal for solar generation, so this 8.28 kWp system is estimated to produce 7’284 kWh annually.
To mitigate shading from trees and maximise the system’s lifespan, we chose Enphase IQ8HC microinverters. These have a peak output of 384W, giving us an oversizing of around 121%. This is ideal to boost performance in the UK’s cloudy climate.
The garden’s electricity usage is quite low, so the majority of the financial benefit comes from selling excess generation to the Grid. After a G99 with SSEN application, the site was approved for its full export rate!
A Detailed Look at their System
There were a few key, unique aspects of this installation that made it slightly more complicated than typical installations. The wood cabin built by Nordic Room has a wooden roof covered by bitumen shingles. This is not a typical construction in the UK so finding an MCS compliant mounting system was a bit of a challange.
Solar Mounting on a Bitumen Roof
G99 Applications
Since the site’s annual usage is less than 2200 kWh we knew that the system would be producing way more than the site needed, especially over summer! Therefore it was important that we could export at a high rate to ensure that energy production wasn’t lost. However, with any G99 application there is no guarentee that the export limit would be extended beyond the guaranteed 3.68kW.
This left us with a few options to consider. Firstly, we could reduce the size of the solar PV array. Although this would reduce the sites production it would also reduce the sites savings and affect how future proof the system would be. Additionally, it is our general advice to maximise the number of panels you install as there is no cheaper time to add panels than when you have an installation team on site. The next option was to install battery storage so that excess energy could be stored and then exported later when the export is below the limit. This is viable, but the battery capacity required to do this would have cost more than it was worth.
So what did we settle on? After discussions with the garden’s trustees, we determined that the best plan was to install a large system, but ensure it was G100 compliant so that export could be limited if we were imposed with an export limit. Since the panels and microinverters all have a 25-year warranty, the garden would be well placed to reapply for a higher export limit if any upgrades happen in their area.
When Are Micro-Inverters A Good Idea
For most solar installations, microinverters are unnecessary, especially if you want battery storage. Microinverters convert DC electricity, produced by your solar panels, directly to AC electricity, which is used by your home. This happens on a panel-by-panel basis, maximising the production of each panel by allowing it to remain unaffected by any panels it is connected to. This is especially beneficial if you deal with intermittent shading from nearby buildings or trees.
However, converting from DC to AC on the back of the panel means that if you do want battery storage, you will incur additional losses, as you will need to convert back to DC to be stored in a battery. So, if you are considering a solar-only installation, micro-inverters might be a great idea for you. If you would like more information about the different types of inverters and their benefits, you can check out our blog post looking specifically at that.
If you are interested in a commercial or residential installation, feel free to get in contact, and one of the team will talk you through the various options available to you so that you can be certain you get a system that’s best for you!
What They Had To Say
Great service from Zion Energy, who worked hard to get the right specification for the PV system mounted on our large wooden cabin.
Installation was efficient and technical support has been excellent.
Highly recommended and worthy of their accreditation as a Which Trusted Trader.
– Andrew C