Electricity - an ongoing technical discussion

[whole diary]

[Red Squirrel]

I think storage of surplus wind energy is on the list, right after we have cracked fusion power (under research since 1920, jam promised tomorrow many times).

According to Mystic Squirrel, the infernal combustion engine as a power source for road vehicles will be more-or-less dead in 20 years*. That means that quite soon there'll be a lot of surplus 8 to 10-year-old lithium-ion car batteries that have lost 30-40% of their capacity which, by definition still have 60 to 70% of their capacity - which is a lot. Grid storage, anyone? Plus all those electric cars plugged in to the mains could be used for grid storage too. And what about all those cars in station car parks?.

* Flight of fancy? Maybe. Maybe not.

[stuving]

... Grid storage, anyone? Plus all those electric cars plugged in to the mains could be used for grid storage too. And what about all those cars in station car parks? ....

Oh, researchers looking at system planning have indeed been casting envious eyes at all that on-line storage. But that's several steps ahead. For a start, the electronics isn't designed to push power backtheway.

So a first step would be to time the charging of all plug-ins (hybrid or pure electric) to when the power is most available. Currently most of them (few though they are) are plugged in immediately on getting home from work, so as to nicely overlap with the day's peak demand. As no-one has yet (AFAIK^▸ (as far as I know)) provided any incenitve for people to shift this to overnight, we don't even know how willing they would be to do it.

[Electric train]

AIUI^▸ (as I understand it) (which is far less than other people who have already posted) 50Hz is the frequency used throughout Europe, including Russia, and North Africa, regardless of local distribution voltages, precisely so that the voles, anbarons and electric toads can be shunted across borders.

North America is 60 Hz

50 cycles is indeed the standard virtually throughout Europe, and does to an extent facilitate interconnection between neighbouring countries. There are however practical problems in interconnecting too large a geographical area and also problems in the operation of AC transmission lines of more than a few hundred miles.

Therefore many international interconnectors are in fact DC^▸ (Direct Current). The UK^▸ (United Kingdom) has interconnectors to France and to Holland, and others are planned. These all use DC thereby avoiding any need to synchronise the UK and continental systems despite both working at 50 cycles.

UK grid data may found via the link below, showing frequency, total load, import/export flows and from what sources electricity is being generated.

http://www.gridwatch.templar.co.uk/

There are other reasons for using DC cables as interconnectors, inductive and capacitive reactance is not a issue with DC as it is with AC; with AC you need to insulate to the peak Voltage and not the normally stated RMS value therefore the insulation at 400kV AC is greater than 400kV DC.  With DC you only need 2 conductors + and - with AC you need , DC systems do not need an earth reference AC requires an earth reference to discharge the induce and capacitive voltages, DC interconnector still needs to be monitored for first earth fault though

[Red Squirrel]

As no-one has yet (AFAIK^▸ (as far as I know)) provided any incenitve for people to shift this to overnight, we don't even know how willing they would be to do it.

Not quite true - good old Economy 7 is an incentive, isn't it? That's why the neo-clarksonites can claim with some justification that electric cars get their juice from fossil fuels, as these power stations seem to like working nights.

[TonyK]

So a first step would be to time the charging of all plug-ins (hybrid or pure electric) to when the power is most available. Currently most of them (few though they are) are plugged in immediately on getting home from work, so as to nicely overlap with the day's peak demand. As no-one has yet (AFAIK^▸ (as far as I know)) provided any incenitve for people to shift this to overnight, we don't even know how willing they would be to do it.

Economy 7! I don't think it would be worth changing to that just for one car, though. I have heard plans to encourage us to put the washing machine and other appliances on before going to bed when we get smart meters, which sounds dumb to me. I'll put all my lights on instead - they are quieter.

[stuving]

As no-one has yet (AFAIK^▸ (as far as I know)) provided any incenitve for people to shift this to overnight, we don't even know how willing they would be to do it.

Not quite true - good old Economy 7 is an incentive, isn't it? That's why the neo-clarksonites can claim with some justification that electric cars get their juice from fossil fuels, as these power stations seem to like working nights.

By "this" I meant charging cars. But where Economy-7 survives I guess it would by a first step, at least if it's the real thing (i.e. all usage gets the night rate). But I though there was not much still in place, and are any new ones being put in?

[TonyK]

* Flight of fancy? Maybe. Maybe not.

The subject of that piece is Elon Musk, whose company SpaceX accomplished the major feat of landing the spent first stage of a Falcon rocket on a barge in the ocean. He said before then that the space transport business was less technologically challenging than the electric cars.

[Red Squirrel]

Aye. Ee's a birruvua lad, our Elon.

[Red Squirrel]

...where Economy-7 survives... ...are any new ones being put in?

Interesting question, which set me off a-googling. My understanding from this is that the major suppiers do still offer Economy 7 tariffs, though they don't tend to advertise them. But there is a debate among the (growing!) EV community as to whether you should use dirty overnight fossil-generated power, or that which comes from your PVs during the day...

[ellendune]

Economy 7! I don't think it would be worth changing to that just for one car, though. I have heard plans to encourage us to put the washing machine and other appliances on before going to bed when we get smart meters, which sounds dumb to me. I'll put all my lights on instead - they are quieter.

This would definitely be against the advice of the fire service.  If you have ever been woken in the middle of the night by a domestic appliance fire you would follow that advice!

[Chris from Nailsea]

I used to live in a second floor flat, and I received some adverse comment from my neighbours downstairs when I put my washing machine on during the economy 7 timeframe. 

[stuving]

...where Economy-7 survives... ...are any new ones being put in?

Interesting question, which set me off a-googling. My understanding from this is that the major suppiers do still offer Economy 7 tariffs, though they don't tend to advertise them. But there is a debate among the (growing!) EV community as to whether you should use dirty overnight fossil-generated power, or that which comes from your PVs during the day...

Maybe what I said is now a bit out of date. BG^▸ (Brake Gangway (carriage)) for one offer an off-peak rate if you are prepared to have a smart meter (or already have one - of the right kind). Ecotricity, on the other hand, don't. But of course peak loading isn't inherently an energy supplier's issue, is it?

[Red Squirrel]

However Ecotricity offer 1,000 miles' worth of electricity per year to registered EV/PHEV owners (or over 2,000 if you're on their Economy 7 tariff). Which sounds pretty generous until you realise that that's only forty quid.

[Chris from Nailsea]

On the other hand, I now live in a detached house, with a dishwasher and washing machine positioned on the solid concrete ground floor - so I still tend to put them on overnight. 

[ellendune]

On the other hand, I now live in a detached house, with a dishwasher and washing machine positioned on the solid concrete ground floor - so I still tend to put them on overnight. 

Solid ground floor did not make any difference. Still could have killed us, ^50k insurance claim and 4 months without a kitchen. 

Oh and I know of at least one other person who has had the same experience. 

If you are asleep you are in more danger as you are absolutely relying on a smoke alarm to wake you.  At least if you are awake you have a better chance. Fire service were very clear in their advice never to leave washing machines, dishwashers and tumble driers on while you are asleep and not while you are out.  Some tenancy agreements also place liability on tenant if such an appliance is left on while unattended.