There is a centralised clock - already used in fact. It's called Greenwich Mean Time, provided by the  National Physics Laboratory.


Much has been said about the inertia of rotary generators. If the load on the grid increases, the generator speed decreases. The governors sense this and cause more steam to be injected until a new equilibrium is reached where the generation once again matches demand. The kinetic energy released as the generators lose speed provides the shortfall between turbine power generated and demand.


We are now running at slightly reduced frequency - an offset compared with target frequency. Hence the grid "clock" running slightly slow compared with Greenwich time. As long as this situation persists, a time disparity, i.e. difference between grid time  and Greenwich time, builds up. The object is to eliminate this disparity. It is theoretically possible to feed back the disparity into the turbo-generator speed control system. In Control Engineering terms, integral action eliminates the offset.  


In the days when I worked in the electricity supply industry (1960s), this level of automation was not applied, to my knowledge, though the technology was available then. Grid control engineers preferred to adjust things manually by calling power stations to deliver requested output. Apart from the consideration of  maximising usage of the most efficient plant, issues affecting the locality of individual power stations could make it impracticable to use them to try to regulate grid frequency automatically. Nowadays there is the additional complication of regulating the trading among the many private power providers. My guess is that there is still a lot of manual control - does anyone have up-to-date knowledge on this?


Inverters have no inertia, and I am not sure it is desirable to design them to simulate inertia. Their output frequency is not affected by load, and can "lock-in" to an existing mains frequency. We could provide a control frequency by radio transmission. There are ways in which we could regulate power output if desired, though it would be sensible to divert excess power to battery storage.

On a grid system powered by solar power we would certainly lose the stability provided by inertia. However, this is hypothetical, since I cannot envisage such systems. Solar panels are not very clever at night. Also bear in mind that nuclear power, though not strictly renewable, is virtually carbon free and is going to be with us for a good while yet. It is going to be some time before we worry about losing the stability of inertia.



 

There is a centralised clock - already used in fact. It's called Greenwich Mean Time, provided by the  National Physics Laboratory.


Much has been said about the inertia of rotary generators. If the load on the grid increases, the generator speed decreases. The governors sense this and cause more steam to be injected until a new equilibrium is reached where the generation once again matches demand. The kinetic energy released as the generators lose speed provides the shortfall between turbine power generated and demand.


We are now running at slightly reduced frequency - an offset compared with target frequency. Hence the grid "clock" running slightly slow compared with Greenwich time. As long as this situation persists, a time disparity, i.e. difference between grid time  and Greenwich time, builds up. The object is to eliminate this disparity. It is theoretically possible to feed back the disparity into the turbo-generator speed control system. In Control Engineering terms, integral action eliminates the offset.  


In the days when I worked in the electricity supply industry (1960s), this level of automation was not applied, to my knowledge, though the technology was available then. Grid control engineers preferred to adjust things manually by calling power stations to deliver requested output. Apart from the consideration of  maximising usage of the most efficient plant, issues affecting the locality of individual power stations could make it impracticable to use them to try to regulate grid frequency automatically. Nowadays there is the additional complication of regulating the trading among the many private power providers. My guess is that there is still a lot of manual control - does anyone have up-to-date knowledge on this?


Inverters have no inertia, and I am not sure it is desirable to design them to simulate inertia. Their output frequency is not affected by load, and can "lock-in" to an existing mains frequency. We could provide a control frequency by radio transmission. There are ways in which we could regulate power output if desired, though it would be sensible to divert excess power to battery storage.

On a grid system powered by solar power we would certainly lose the stability provided by inertia. However, this is hypothetical, since I cannot envisage such systems. Solar panels are not very clever at night. Also bear in mind that nuclear power, though not strictly renewable, is virtually carbon free and is going to be with us for a good while yet. It is going to be some time before we worry about losing the stability of inertia.