Talk Morgan Forums Community The Malvern Arms Renewable Reality

Actually if you have the PV system linked to grid which nearly all are, then any disruption to grid (voltage/frequency etc) supply will result in the PV inverter shutting down instantaneously as a safety requirement and it takes the inverter about 3 minutes to start up again once all the grid requirements are met. In the UK its classed as G98 (single phase) and G99 (3 phase) regulations.

Some of the many reason's that these huge warehouses don't get covered in Solar panels are:

1/ large roof installations are more costlier than a large ground mount to install.

2/ These warehouses normally have only a grid connection that cover the needs of the warehouse which won't be much compared to say a manufacturing facility - therefore you can only install a PV system that will not exceed the sites incoming fuse/cable capability.

3/ Legal nightmare as the occupiers of the warehouses are rarely the owners of - therefore legal consents for renting of roof space etc etc

4/ No requirement in planning to install Solar PV - idiotic but hey that's Government policy for you!

Interesting post, thank you....

IMHO - your friend could fit a 6kWp inverter with an export limiting device set at 3.68 kWp (16A) - will cost probably £300 but will solve his issue.

Don't forget that prior to installing an EV charger or a battery storage system, they will also need DNO (District Network Operator) approval beforehand especially battery storage as its classed as a generator same as PV. So if your fitting a >3.68kWp inverter and a battery storage system and an EV charger then you need 3 sets of approval.

Regarding the Solar generation getting back to grid, true in the sense it probably doesn't get back to the 400kv transmission network but it does get back to the local 11/33kv network that powers all the substations etc.

Now nearly all of my larger UKPN systems are export limited to 200 kWp - which means fit as much as you want (say 400 kWp) but your only ever allowed to export 200 kWp to the grid. (may only occur on a sunny Sunday in July when factory is shut so low consumption=high export).
Basically the grid local infrastructure can't deal with all the possible embedded generation applications that might be submitted so they are already starting to restrain the network.

I was involved in building a new off grid warehouse and manufacturing site in Cape Town. Energy demand wasn't so high. The solar also powered a bore hole water supply. At night the local grid provided power as needed.

That's not a true off grid system - its just a standard grid connected system where the Solar PV output has been designed to match site load during daylight hours. If you turned the solar off then the grid would still supply the site as it does during the night.

I have a 4Kw system with battery backup installed. Is there any point in renewing the battery when it reaches its end of life?

Bob,
I have a 3.9kW array installed & 4.2 kWh batteries on order now for nearly a year. They will we hope (4th time a date has been booked) be installed in early Novemeber 13 months after order. I reckon at 52p kWh the payback is 4.7 years. At the current 29p it is jusr over 8 years.

We generate an average of 11.7 kW per day over the last 4 years. We divert any excess now to heat our hot water first. From May to October we use little / no gas. this year it is 16 units so far (only gas rings on the cooker). We use in the same period 4kWh per day of electricity, so with batteries we would be off grid.

The batteries obviously deteriorate over time so I guess you need to consider if it is replace or supplement the stack. My installation can have 5 batteries on a stack and the 4.2 kWh is only 2 slots. When I last looked they were c£1k each battery.

Thank you John. I had a power cut recently and there didn't seem to be any electricity available from the battery. Is this normal?

Yes. For safety reason the system shuts down. If the repair team are working on what they think is a dead power system in the area then you exporting power puts them at risk. You can get a single socket fitted to the batteries to use them as a UPS (uniteruptable power supply), but that was another £300 so I didn't buy it.

Interesting stuff all this, keep it coming chaps