24-03-2026, 12:17 PM
(This post was last modified: 24-03-2026, 12:21 PM by ppppenguin.)
All G83 compliant inverters https://dcode.org.uk/assets/uploads/ENA_..._2019_.pdf stop generating if the mains supply fails.
I have had PV at home since 2011. On the very old FIT scheme I get paid on the basis of amount generated. The amount exported isn't measured. Modern meters won't go backwards.
At the Broadcast Engineering Museum we have had PV since 2022. We have a smart meter that measures both import and export. The export side has a separate MPAN. We sell any surplus under the SEG scheme. Our new contract starting in May will be for 15p/kWh export and 23p/kWh import (both exc VAT).
Batteries are usually stated to have a 10 year life. Usual rule of thumb is that a battery capacity in kWh should be twice the panel rating in kWp. Another rule of thumb is that you can save about half the energy that you would otherwise export. Take the difference between your import and export price. Multiply by the number of kWh you export (you won't know this until you had a system for a year) and compare to the cost of a battery. If you can't pay back the cost of the battery in under 10 years it's not worth having.
You can get some idea of the amount you export by assuming a specific yield of between 500 and 1000 kWh per kWp per year. Depends on orientation of panels. Then assume you export half of it.
I've no idea about export tariffs for plug-in panels.
PS: For the 30kWp array on the south facing roof of the Broadcast Engineering Museum our specific yield is about 1000kWh/kWp/year. We generate about 30,000kWh per year and export about 18,000. Batteries are not yet worth it for us. We're about to fit more PV that's north facing. The yield will be about half that of the south facing panels. The economics still work well for us.
I have had PV at home since 2011. On the very old FIT scheme I get paid on the basis of amount generated. The amount exported isn't measured. Modern meters won't go backwards.
At the Broadcast Engineering Museum we have had PV since 2022. We have a smart meter that measures both import and export. The export side has a separate MPAN. We sell any surplus under the SEG scheme. Our new contract starting in May will be for 15p/kWh export and 23p/kWh import (both exc VAT).
Batteries are usually stated to have a 10 year life. Usual rule of thumb is that a battery capacity in kWh should be twice the panel rating in kWp. Another rule of thumb is that you can save about half the energy that you would otherwise export. Take the difference between your import and export price. Multiply by the number of kWh you export (you won't know this until you had a system for a year) and compare to the cost of a battery. If you can't pay back the cost of the battery in under 10 years it's not worth having.
You can get some idea of the amount you export by assuming a specific yield of between 500 and 1000 kWh per kWp per year. Depends on orientation of panels. Then assume you export half of it.
I've no idea about export tariffs for plug-in panels.
PS: For the 30kWp array on the south facing roof of the Broadcast Engineering Museum our specific yield is about 1000kWh/kWp/year. We generate about 30,000kWh per year and export about 18,000. Batteries are not yet worth it for us. We're about to fit more PV that's north facing. The yield will be about half that of the south facing panels. The economics still work well for us.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
