Electricity - an ongoing technical discussion

[whole diary]

[Chris from Nailsea]

Hmm. 

I was referring merely to the noise / vibration impact on my neighbours of my use of some domestic electrical appliances overnight.

In the flat, it was probably a bit of an inconvenience, to those living immediately below me - but in my house, now?

I'm puzzled as to how a domestic fire caused by any electrical appliance is more likely to occur overnight than it is during the day?

We have smoke alarms, which are active 24/7 ... 

[JayMac]

It's not that fires caused by domestic appliances are more or less likely overnight. It's the increased risk such a fire presents to people who are asleep when it breaks out.

Smoke alarms aren't in every home. And even when they are present, the time between activation and the rousing of slumbering householders could be the difference between life and death.

I'd never put my washer/dryer on at night just to save a few pence on a cheaper tariff.

[Chris from Nailsea]

Fair comment: we're actually not on any cheaper tariff overnight - and at least one of the three adult residents (and two dogs) in this household will be awake at any one time. 

[broadgage]

We are on economy 7 and find it a useful saving.
The washing machine is run during the off peak time, I was not aware of any advice not to run washing machines unattended and I am about to fit a smoke detector above it.

Several dehumidifiers are also used during the off peak hours.
In cold weather an electric heater is used for just the last 45 minutes of the off peak tariff in order to take off the early morning chill, before the wood stove is lit.

[Bmblbzzz]

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/

That's interesting. I vaguely remember reading about DC transmission lines in Siberia and Russia's Far East, where the lines are obviously very long indeed. But I've also read about a 50Hz transmission 'ring' around the Mediterranean. Neither particularly specific or informed memories though.

[stuving]

That's interesting. I vaguely remember reading about DC^▸ (Direct Current) transmission lines in Siberia and Russia's Far East, where the lines are obviously very long indeed. But I've also read about a 50Hz transmission 'ring' around the Mediterranean. Neither particularly specific or informed memories though.

Much of Europe (plus some neighbours too) operates as a single synchronised 50 Hz grid, despite being controlled as separate national or smaller systems. The links between these are a mixture of AC and DC, and that's true of new ones being planned within this grouping - between Germany and Belgium, for example, using DC. There's a big network plandiagram (for those* who like that sort of thing) here. Mind you, I'm not sure it's accurate in all its details - it shows almost all the hydro schemes in Scotland as combined generation and pumped storage, which I think is not true.

* This may be a defining characteristic of members of this forum, I suspect.

[TonyK]

Much of Europe (plus some neighbours too) operates as a single synchronised 50 Hz grid, despite being controlled as separate national or smaller systems. The links between these are a mixture of AC and DC^▸ (Direct Current), and that's true of new ones being planned within this grouping - between Germany and Belgium, for example, using DC. There's a big network plan (for those* who like that sort of thing) here. Mind you, I'm not sure it's accurate in all its details - it shows almost all the hydro schemes in Scotland as combined generation and pumped storage, which I think is not true.

* This may be a defining characteristic of members of this forum, I suspect.

Suspicion confirmed!

Plans are afoot for a HVDC link to Iceland, which generates all of its non-vehicular energy from natural sources, particularly geothermal heat, and has power to spare. It will be the longest so far into Britain. There is also a bi-directional link with the Irish republic. There were plans for a huge windfarm to generate power for the UK^▸ (United Kingdom), which have not gone down well with the locals.

[ellendune]

Plans are afoot for a HVDC link to Iceland, which generates all of its non-vehicular energy from natural sources, particularly geothermal heat, and has power to spare. It will be the longest so far into Britain.

Some including myself doubt whether it is practicable or economic. 

[John R]

Better to have an underwater pipe bringing all that hot water to the UK^▸ (United Kingdom). I'm sure with a bit of insulation it'll keep nice and warm, and turn Lewis into a tropical paradise where it comes back up to land.   

[TonyK]

Some including myself doubt whether it is practicable or economic. 

I think the length of the conductor would be nearly 250 miles. That isn't the shortest route to the UK^▸ (United Kingdom), but it misses out Scotland because of the paucity of capacity there. The losses over that distance would be huge, but Iceland has spare electricity, generated with no environmental impact beyond building the plant, and we need some of that action. Iceland has a population not much more than half that of Bristol, and is looking to hydrogen production to replace petroleum fuels in vehicles, so giving it the possibility of entirely fuelling the country with no emissions - if you ignore the muck chucked out by Eyjafjallaj^kull in 2010, and others since. I shall be there next month, and shall ask questions.

Economy 7 and similar tariffs have had something of a change in purpose over the years. When we were a nation of nuclear power station builders, the idea behind them -and Dinorwig - was a way to store up all the excess power generated after we had all largely gone to bed. Nuclear and coal fired power stations are slow to start up or slow down, and work best at full pelt for as long as maintenance schedules permit. They would thus provide the base load - the minimum needed when UK PLC is ticking over. Other means, mainly gas these days, would supply the rest. Come 2016, however, and there isn't any spare nuclear or coal power as the stations have been closed. Add those to wind and solar power, and you still end up with around half of the base demand. Economy 7 has now become a way of balancing demand rather than storing excess power, with the grid in mind rather than the generators. Dinorwig is now the fine-tuning mechanism, able to supply significant power within seconds, and to shut down just as quickly without waste. The only way coal and nuclear stations (and early gas) could react to a sudden drop in demand was to pour their boiling water into the cooling towers without it being used to generated electricity - very wasteful.

Economy 7 could be described as an anachronism because of this, but a lot of small conurbations without access to mains gas still use storage heaters as a form of central heating (my cottage included), and for as long as that is the case and it still suits the power companies, it will continue.

Like Red Squirrel, I believe that in time the only use of oil in transport will be as a lubricant and possibly an insulator. Combined heat and power plants will be the norm in many cities, using either natural gas (much of it obtained from shale rocks) or small nuclear power plants, maybe using Thorium rather than Uranium as the fuel. Other heating appliances in homes will be highly efficient electric appliances, cooking will be by magnetic induction, which uses a third of the power burnt by a traditional hotplate, and developments in LED lighting will continue to drive down the price and power consumption. I have recently bought LED bulbs at ^9.99 for five which use 8W, but happily replace a 100W bulb. The light is warm and hardly different in quality from what we have been used to all these years - certainly better than the fluorescent energy saving bulbs.

[stuving]

250 miles would not even reach the Faroes - the routes being considered for IceLink are around 1200-1500 km. The Norway-Great Britain NSN, which is being built now from Northumberland to Norway, will be 720 km long. So it probably looks, to the guys building these things, like the next step up.

[TonyK]

250 miles would not even reach the Faroes - the routes being considered for IceLink are around 1200-1500 km.

And to think I studied navigation for aviation! Looking at the various pieces about this, yes the shortest route would be 1000km, and that's to northern Scotland. Longer subsea cables have been built of course, but for communications. They don't have high voltage, and have boosters along the way. The capacity could be the equivalent of a new nuclear power station.

At least one of the contenders is offering to supply and finance the whole project, including new power stations in Iceland. There is plenty of spare hot rock there and, to confound Mark Twain's famous advice, new bits continue to appear. Presumably they will want a strike price that will pay for it, and it might not be beyonds the bounds after all.

[Chris from Nailsea]

Hang on a minute! 

Don't some of those Icelandic Banks still owe us (various UK^▸ (United Kingdom) local councils) a fortune in lost investments?

[ellendune]

Hang on a minute! 

Don't some of those Icelandic Banks still owe us (various UK^▸ (United Kingdom) local councils) a fortune in lost investments?

No I think they - or the Icelandic Government - have now paid it all back. 

[Chris from Nailsea]

Oh, right.  Thanks for that. 

So, giving lots more money to private power companies in Iceland is quite secure now, then?