Effective Utilization of Solar Power in the electricity industry during summer.

Can we say that electricity generation from solar PV systems is under-utilized?

From the point of view of are we using all the PV output - the answer is probably no at the moment (at least in the UK). If you look at this for example: https://electricinsights.co.uk/#/dashboard?period=7-days&start=2026-07-14 you'll see that even in the height of summer PV generation (yellow) seems to follow the daily peak in demand quite nicely, and there's still some combustion based generation going on even during peak PV production - so we're still using renewables to displace fossil (mostly gas) generation - so 100% of PV generation gets usefully used. AFAIK solar systems don't normally get asked to reduce output in the same way that large wind farms can be. No doubt that some are using immersion-heater diverters - which I suppose isn't really the ideal use of high grade electricity (solar thermal would be better) - but I suspect that's a small piece of a big picture.

In time though, we'd hope that renewable production would increase and so we should get to the point (maybe not in the too distant future now) where PV production does exceed instantaneous demand - and then it would be under-utilised as you say. Home battery storage is are already making inroads in that area, grid-scale batteries also. Pump-storage (e.g. Dinorwig) was one of the traditional grid-scale storage solutions. My feeling is that we could have a lot more smaller scale pump-storage (if lower head than Dinorwig) - around these parts ("up North") we often see chains of two or three reservoirs down the same valley - I reckon some modest pump-storage could be incorporated into those at reasonable costs (all the big civils has already been done for you) and with only a modest loss of peak water storage capacity. Schemes to alter demand to match available generation is another road (again not new in principle) and in many ways easier then it used to be as many of the new loads (EVs and heat pumps) aren't that time critical.

  - Andy.

Can we say that electricity generation from solar PV systems is under-utilized?

From the point of view of are we using all the PV output - the answer is probably no at the moment (at least in the UK). If you look at this for example: https://electricinsights.co.uk/#/dashboard?period=7-days&start=2026-07-14 you'll see that even in the height of summer PV generation (yellow) seems to follow the daily peak in demand quite nicely, and there's still some combustion based generation going on even during peak PV production - so we're still using renewables to displace fossil (mostly gas) generation - so 100% of PV generation gets usefully used. AFAIK solar systems don't normally get asked to reduce output in the same way that large wind farms can be. No doubt that some are using immersion-heater diverters - which I suppose isn't really the ideal use of high grade electricity (solar thermal would be better) - but I suspect that's a small piece of a big picture.

In time though, we'd hope that renewable production would increase and so we should get to the point (maybe not in the too distant future now) where PV production does exceed instantaneous demand - and then it would be under-utilised as you say. Home battery storage is are already making inroads in that area, grid-scale batteries also. Pump-storage (e.g. Dinorwig) was one of the traditional grid-scale storage solutions. My feeling is that we could have a lot more smaller scale pump-storage (if lower head than Dinorwig) - around these parts ("up North") we often see chains of two or three reservoirs down the same valley - I reckon some modest pump-storage could be incorporated into those at reasonable costs (all the big civils has already been done for you) and with only a modest loss of peak water storage capacity. Schemes to alter demand to match available generation is another road (again not new in principle) and in many ways easier then it used to be as many of the new loads (EVs and heat pumps) aren't that time critical.

  - Andy.

Thanks for using this in explaining and supporting your points. Quite useful and beneficial!

AJJewsbury said:

get to the point (maybe not in the too distant future now) where PV production does exceed instantaneous demand

Are you sure that we are not already there Andy?  My supplier (EON) and I believe others are offering rewards to use more electricity at certain times of the day, usually between 1.00 pm and 3.00 pm, when I use - 0 kW, my solar feeding into the grid.

David

davidwalker2 said:

Are you sure that we are not already there Andy? 

It is possible - I'm just guessing about the inputs based on the observed output and a (partial) understanding of the rules. Some things don't altogether make sense ... e.g. at times the wholesale price is -ve (suggesting an oversupply - try 2nd July at about 17:20 for an example if you're looking at the Drax charts) yet we're still burning gas (usually the most expensive) - so there's certainly more going on than meets the eye (maybe they can turn down gas generation, but turning it off is more difficult?) I suspect much of the "oversupply" comes from wind rather than PV (not that makes a difference in the big picture), but in terms of the OP's question it's not the PV that gets curtailed - so in that sense the PV is "all used" - so fully utilised as it were.

  - Andy.