Off-Grid Solar PV Case Study For a Large Self-Build Project

No grid, no problem! Self-build project, Shaftesbury

Vanessa & Bruce Jannion along with their 2 children, Rory and Freya have always dreamed of building their own home in the country. Vanessa grew up in rural Somerset, so after living in London for a few years with a holiday home in the Shaftesbury area they decided to make a permanent move to the area in 2006. After being inspired by watching programs such as Grand Designs and loving the idea of a modern house with the advantages of open plan living, great insulation and being able to incorporate green energy into their home, the family embarked on their self-build project.

The first challenge was to find a plot of land to build on as there was a huge scarcity of plots in their area. After searching for a long time, their perseverance paid off and they found a steel-framed barn which was only 3 miles away from where they lived, in December 2016. They fell in love with the beautiful views and loved the shape of the barn which offered great potential to convert a building that previously housed cattle into their 400sqm 5 bedroom forever home.

As the barn had never been occupied as a home before Vanessa and Bruce always knew they would need to bring utilities in as part of the build. They did not, however, envisage that this would end up being far and away the biggest challenge of the entire project. The nearest electricity connection was 500m away from the property, and the cable would need to run across neighbouring land. Vanessa and Bruce tried very hard to negotiate wayleave agreements with the landowner but they would not agree. This meant the only option was a very expensive in-road dig which would cost well in excess of £100k! Even if their neighbour had been willing to negotiate a wayleave agreement when you add together the charges from SSE who are the local district network provider, the compensation to the landowner, trenching works and legal costs the connection costs would have been over £50k!

During the 2 year struggle to obtain a grid connection, Vanessa and Bruce considered the option of an ff-grid solar PV system but were always told their project was too big and their electricity demand was too high for this to be a viable option. Then in April 2019 Vanessa spoke to Ian Hewson from Off Grid Engineering. Ian was able assure Vanessa and her building team that an off-grid solar PV set up was an option and went about designing the perfect system for the project.

Firstly Ian assessed the electricity demand for Field View Barn. Ian worked very closely with the heating engineer who was providing an air source heat pump as the main source of heating. Ian needed to ensure the system had the capacity to run the heat pump in winter whilst there were shorter days and less energy generated from the solar panels.

Here is the system that Ian designed:

  • 80 x 335W JA Mono-Crystalline Solar Panels
  • 80 x Renesol Console+
  • Victron 15 kva Quattro
  • 3 x 13.8 Kwh BYD Li Fe PO4 battery bank
  • 4 x 250V/100A Victron Smart charge controllers
  • Octa GX / 4G off grid wifi internet hub
  • 20 Kva LPG generator

Once Ian had established what size system Field View Barn required he then assessed the site to find the best location to place the equipment. Vanessa and Bruce have a beautiful metal clad roof with a lot of glass incorporated into it. As the roof was already completed and Vanessa has land around her property Ian found a great spot in front of the house to site the 80 solar panels. As this section of land was visible from the road, Ian assisted in obtaining planning permission by liaising with the planning authority on Vanessa’s behalf.

Ian then worked with the project’s build team to specify the trench and work on the area where the panels will be placed. Ian also helped design Field View Barn’s plant room to house all of the equipment needed for the heat pump and the off-grid solar PV equipment such as the batteries, inverters, charge controllers, etc. As Vanessa and Bruce’s system was being monitored remotely by Off Grid engineering using the Victron web-based portal, Ian installed a Twoot which is a 4G internet hub to provide an internet connection. Ian was able to utilise the Twoot device to provide an outlet for the heat pump technology also. This meant that Vanessa and Bruce can relax in the knowledge that all of the vital equipment that provides heat and electricity to their home is being regularly monitored to prevent any downtime and ensure the systems are working to the maximum efficiency.

Field View barn is complete, although Vanessa and Bruce are now focusing their attention on landscaping the area around the barn. Reviewing the project Vanessa is really pleased with their decision to complete a self-build project. We asked Vanessa if she has any advice for any potential self-builders who are thinking of carrying out their own projects, Vanessa said “Don’t give up on the search for a plot, ensure you have the best team you can, from architect to engineer to main contractor. Engage the services of a quantity surveyor at the outset to give you a realistic costing and if converting a building that has never been a house to carefully check costs for bringing in utilities.”

Both Scott and Ian really enjoyed working with Vanessa and Bruce and providing an off-grid solar PV solution to their grid connection issues. I think everyone will agree that Field View barn is a beautiful home that the family will enjoy for many years to come.