Bidirectional Electric Vehicle charging - could this be a game changer to support widespread EV adoption whilst strengthening the grid?

Does it switch off the loads before things get out of hand?

Not so much switching things off, as co-ordinating the times they're switched on. It's not a new idea after all - we've had off-peak supplies for storage heaters etc for donkey's years.

In some ways it's interesting to compare the French system with ours - on the face of it they have a very weak distribution system and domestic consumers typically limited to 30A or 45A single phase - yet they use far more electricity per head than we do. They were driven by the demands of their fleet of nuclear power stations of course - being not very 'switch on an offable' - they were forced into designing a system that spread the loads far more evenly - strict limits on instantaneous demand mean that things like 10kW instantaneous electric showers are unknown over there - for hot water they're use an immersion in a pressurised cylinder -  so not only replacing a very spiky 10kW load with something like a 3kW one, but normally shifting it to the night-time off peak as well - so win-win from a generation and distribution point of view.

I recall a TV interview with someone from the national grid - he made the point that while at peak times we don't have much spare capacity (either generating or distribution), for the vast bulk of each day we're not at peak ... so there is quite a bit of space capacity most of the time - if we can slot the new demand into those gaps, it should be doable.

Fortunately things like space heating, water heating and EV charging aren't particularly time sensitive (or can be made so relatively easily - e.g. with buffer tanks) - so it is looking technically possible to me.

    - Andy.

Obviously the French grid is totally different to the uk.

Due to its majority Nuclear generation, they can endulge in using energy without the worry of black out.

But..in the UK we have no decent base generation left as net zero looms.

There are 30 million UK homes.

If each house has a 5KW heat pump running 24/7

150GWhr we're screwed.

Power rationing will have to happen.

Someone will be in control of my energy, decreeing when I can have it and when not.

If I've diligently charged my car and then find the power sucked out of it when I'm about to use it, that would.be inconvenient.

Due to its majority Nuclear generation, they can endulge in using energy without the worry of black out.

Probably fairer to say they have different constraints - their difficulty is responding to short term peaks in demand - so they have to use techniques (such as a 30A limit for domestics) that might feel quite draconian to us ... but with a little engineering nous proved to be quite workable.

If each house has a 5KW heat pump running 24/7

It's a pretty poor house average size house that needs 15kW of heat to keep it warm (presuming a COP of 3) (don't be fooled by the size of typical gas boilers - combi boilers are usually sized for the instantaneous domestic hot water demand, rather than space heating and even conventional boilers were typically oversized to 'be on the safe side', to give quick heat up from cold, and meet the next standard size up). The better answer of course is to insulate, insulate, insulate.  If I can insulate my probably slightly larger than average 1900s stone built semi so that it can stay warm on the coldest Pennine nights for around 3kW, I suspect there's quite a bit of scope to lower demand. New builds should be substantially better than older housing of course, and would have been better still if the government of time hasn't caved in and failed to implement the 2016 building as originally intended -  which even by now would have given us about 1.5 million far better insulated homes.

Someone will be in control of my energy, decreeing when I can have it and when not.

As was ever the case. I don't think anyone's suggesting rota cuts or anything of that nature though. More likely are variable time-of-use tariffs, so those that can will switch their consumption to times of lower demand, so leaving capacity for those than really want it at peak times. Not so different in principle to the old E7/E10 tariffs. Likewise back-feeding from EVs would presumably only happen with the owner's informed consent and within limits (e.g. remaining capacity) they agreed to. If you really wanted to keep your EV at 100% you'd have that option, likewise others who'd like to help out, still have enough capacity for the next day's motoring and earn a few quid into the bargain would have that choice as well.

  - Andy.

Due to its majority Nuclear generation, they can endulge in using energy without the worry of black out.

Probably fairer to say they have different constraints - their difficulty is responding to short term peaks in demand - so they have to use techniques (such as a 30A limit for domestics) that might feel quite draconian to us ... but with a little engineering nous proved to be quite workable.

If each house has a 5KW heat pump running 24/7

It's a pretty poor house average size house that needs 15kW of heat to keep it warm (presuming a COP of 3) (don't be fooled by the size of typical gas boilers - combi boilers are usually sized for the instantaneous domestic hot water demand, rather than space heating and even conventional boilers were typically oversized to 'be on the safe side', to give quick heat up from cold, and meet the next standard size up). The better answer of course is to insulate, insulate, insulate.  If I can insulate my probably slightly larger than average 1900s stone built semi so that it can stay warm on the coldest Pennine nights for around 3kW, I suspect there's quite a bit of scope to lower demand. New builds should be substantially better than older housing of course, and would have been better still if the government of time hasn't caved in and failed to implement the 2016 building as originally intended -  which even by now would have given us about 1.5 million far better insulated homes.

Someone will be in control of my energy, decreeing when I can have it and when not.

As was ever the case. I don't think anyone's suggesting rota cuts or anything of that nature though. More likely are variable time-of-use tariffs, so those that can will switch their consumption to times of lower demand, so leaving capacity for those than really want it at peak times. Not so different in principle to the old E7/E10 tariffs. Likewise back-feeding from EVs would presumably only happen with the owner's informed consent and within limits (e.g. remaining capacity) they agreed to. If you really wanted to keep your EV at 100% you'd have that option, likewise others who'd like to help out, still have enough capacity for the next day's motoring and earn a few quid into the bargain would have that choice as well.

  - Andy.