Solar Panels

A feature of the conventional simple PV system (just panels + inverter, not storage) is that generation often doesn't match on-site demand - no generation at night (often including the evening peak) - so you need to import then, ditto on foggy days or when there's snow covering the panels. Even when generating there are often short times when demand exceeds local generation (kettle and washing machine on at the same time) which again means importing from the grid. On the flip side during most of the day generation will exceed local demand and the excess will be exported (50% of total generation being exported turns out to be a pretty reasonable first approximation). In the big picture that's not a problem as it simply feeds neighbouring installations and reduces demand on the overall grid just the same.  In the old days when generators were being paid (in round numbers) 50p/kWh for generation (whether they consumed it locally or exported it) and imports were 'only' around 15p/kWh most PV owners were happy to allow the exports to go out effectively for free. But now that imported kWh prices look to be well above 50p/kWh I can see many thinking that making better use of site-generated power might be worth while - hence my question about battery systems on another thread.

In many ways - like the current grid prices - we're constrained more by political rather than engineering challenges. If unit prices for export were the same as for import (like in the US where meters simply run backwards for exports) - we could go back to the original idea of using the grid as a battery (at least in the short to medium term)  - 'storage' being implemented by displacing generation elsewhere - in effect the stored energy existing as unburned fuel in the bunkers of conventional power stations or retained as high level water in hydro systems.

Likewise one option for the government for grid prices, since the UK can source the majority of its gas/electricity energy domestically, is to suspend the free market and demand that producers sell at no more than their production costs + modest profit margin to the UK market until domestic demand is satisfied, only allowing any remaining to be sold for export at free market rates. We'd only then be subject to the higher prices for the smaller amount of extra energy we needed to import - so diluting that price effect on final kWh prices to consumers. OK there will undoubtedly be some significant political side-effects (less co-operation from other countries, probably a further increase in world open-market prices as supply to that market declines) but I gather it's just the sort of thing that past governments have done before in times of crisis , and might be worth at least thinking about now.

   - Andy.

A feature of the conventional simple PV system (just panels + inverter, not storage) is that generation often doesn't match on-site demand - no generation at night (often including the evening peak) - so you need to import then, ditto on foggy days or when there's snow covering the panels. Even when generating there are often short times when demand exceeds local generation (kettle and washing machine on at the same time) which again means importing from the grid. On the flip side during most of the day generation will exceed local demand and the excess will be exported (50% of total generation being exported turns out to be a pretty reasonable first approximation). In the big picture that's not a problem as it simply feeds neighbouring installations and reduces demand on the overall grid just the same.  In the old days when generators were being paid (in round numbers) 50p/kWh for generation (whether they consumed it locally or exported it) and imports were 'only' around 15p/kWh most PV owners were happy to allow the exports to go out effectively for free. But now that imported kWh prices look to be well above 50p/kWh I can see many thinking that making better use of site-generated power might be worth while - hence my question about battery systems on another thread.

In many ways - like the current grid prices - we're constrained more by political rather than engineering challenges. If unit prices for export were the same as for import (like in the US where meters simply run backwards for exports) - we could go back to the original idea of using the grid as a battery (at least in the short to medium term)  - 'storage' being implemented by displacing generation elsewhere - in effect the stored energy existing as unburned fuel in the bunkers of conventional power stations or retained as high level water in hydro systems.

Likewise one option for the government for grid prices, since the UK can source the majority of its gas/electricity energy domestically, is to suspend the free market and demand that producers sell at no more than their production costs + modest profit margin to the UK market until domestic demand is satisfied, only allowing any remaining to be sold for export at free market rates. We'd only then be subject to the higher prices for the smaller amount of extra energy we needed to import - so diluting that price effect on final kWh prices to consumers. OK there will undoubtedly be some significant political side-effects (less co-operation from other countries, probably a further increase in world open-market prices as supply to that market declines) but I gather it's just the sort of thing that past governments have done before in times of crisis , and might be worth at least thinking about now.

   - Andy.