Solar electricity panels, also known as photovoltaics (PV), convert the sun’s energy into electricity for use in your home – reducing your carbon footprint and your bills. The sun’s energy is clearly renewable (at least for the next five billion years!), and because most – if not all – of the energy generated will be used on site, domestic PV is very efficient means of generation. Any excess is contributed to the grid.
After many years of wondering and a fair bit of saving up, my family recently took the plunge: last week we had 26 SolarEdge panels fitted to our roof. This is how it went.
Choosing an installer
We’ve got an old house, and live in a conservation area, so I wanted to use a firm I could rely on to fit with care and sensitivity. It wasn’t a difficult choice: Greenshop Solar (Bisley) are long-established and have a reputation for careful and high quality installation. Thanks to the steep pitch of our roof and the number of panels involved (and in sub-zero temperatures!), it took a week to get the panels fitted. The Greenshop team were absolutely brilliant, I can’t recommend them highly enough.
Do I need permission?
Fitting solar panels on your roof, as opposed to on a wall or standalone, doesn’t generally require planning permission, but you do need consent if your home is listed. If you have any concerns, contact the planning department at Stroud District Council (and/or your installer) to discuss them.
We also needed prior permission from the local District Network Operator to connect to the grid because our system is over 16 amps per phase. This takes 45 working days and was arranged by the Greenshop.
How do the finances work?
Sadly the feed-in tariff, a generous scheme which used to reward domestic generators for their contribution to the grid, no longer applies for new installations. It was replaced by the Export Guarantee Payment, if you have a smart meter – this is estimated to be around £160pa for our system – but most of the benefit in a domestic solar array now is in reduced bills and carbon footprint. If we use between half and all of the power generated ourselves (which is likely), we should recover our investment in around 15 years, but the payback period on a smaller, more easily installed system (ours took rather a lot of scaffolding and labour!) would be shorter. We expect to save around 1,800kg of carbon a year.
What sort of panels, and how many?
We’re a family of five, we both drive electric cars, and we have an electric Aga, so our household consumption of electricity is relatively high. So we wanted to maximise generation, without ruining the appearance of the house.
The Greenshop team recommended a SolarEdge system. These panels have a long life (25 year warranty – 12 years for the inverter) and are highly efficient generators. The panels are matt black, so compared to the older, silver framed type, so they are a little less visible. You can also include a battery (something we may add later – the system is modular so this will be simple to do).
When the feed-in tariff was still in operation, people’s focus was getting maximum generation in the day, but for us the focus was on lengthening the period of generation and matching generation to our likely demand. That meant fitting the panels on east and west as well as south-facing roof surfaces, so as to follow the sun as it travels east to west over the day.
How do you know how it’s doing?
The SolarEdge system comes with an app so that you can see at any time how the system is performing, right down to each individual panel. This is geek heaven! You can save energy intensive activities (running the dishwasher, for example) for times when the system would otherwise be exporting power. The Greenshop have access to the system too, so they can monitor the health of panels remotely.
Our panels were fitted in mid-winter, while the sun is low and shy, but we are still generating 20+kWh some days and our costs have already reduced substantially. I can’t wait to see the impact once spring comes!
What about batteries?
As mentioned above, it’s easy to add a battery to the SolarEdge system if you’re looking to smooth out demand. These cost around £6.5k, and they have a shorter useful life than the rest of the system, but demand’s high at the moment – there is a minimum lead time of around nine months. We may choose a different route: interesting new electricity tariffs are starting to emerge which offer the potential to use your electric car as a battery. This wouldn’t work for everyone, but electric cars which sit unused for significant periods, when teamed with microgeneration such as solar, have great potential to smooth demand across the grid. As EDF says:
“Imagine that one in 100 of the UK’s 27 million households own a Nissan leaf. Some 270,000 cars, each with a 40kWh battery could store an incredible 10.8GWh of power to release as needed when renewable generation is lower – that’s more than the UK’s biggest storage facility, the Dinorwig pumped storage plant in Snowdonia.”
Read more about solar panels:
The Energy Savings Trust guide to solar
Greenshop Solar
The Planning Portal – Common Projects – Solar Panels
