Grand Apagon - Electricity (not) in Spain

They have no problem at a few cycles per second, as London Transport discovered in the early days of computers.

London Transport was powered by Lotts Road Power Station. The load was mainly underground electric railways, trams and trolleybuses. but they took the electricity supply for their offices from there too. The first computer they installed kept crashing and the problem was traced to dips in the power supply rails.

After a lot of investigation, they discovered that the AC mains supply had alternate (or perhaps every third) cycles much lower in voltage than the others (and I think there must have been a timing error too). The power supply smoothing capacitors were unable to store enough energy to tide them over the dips and the result was a regular dropping of the 'stabilised' supply rails.

The fault was traced back to Lotts Road, where it was found that a steam valve was constantly cycling due to an unstable control loop. This hadn't had any effect on the trams, so nobody had bothered to do anything about it.

Conclusion: A tram stores more energy than a computer capacitor bank.

I used to design steamship throttle and boiler control systems [1]. A steamship throttle valve hydraulic actuator is powered by low pressure oil (from a standby gravity tank) and slews in a few seconds. But serious high-pressure hydraulic actuators have multi-horsepower outputs and bandwidths of hundreds of Hz.

A decent steam valve will nicely overlap the equivalent bandwidth of a big generator's inertia. Field control can be made fast too.

Control engineers would be better at desiging stable power systems than greenie politicians.

I was once stranded dead in the water in the Gulf Of Mexico/America, with maybe 100 other guys, on a LASH ship sea trial, when the main turbine steam valve actuator locked up and had to be disassembled and redesigned.

They convert the input AC to DC. That part can be shared.

In my case, I have to be aware of everything that is using electricity in the house, and then select the power at the burner, and whether I can use both or not, or the microwave simultaneously.

If I hit the limit, the electricity to the house is cut off, and the procedure to restore is a bit cumbersome.

So far, I have never hit the limit.

I learned today that we can not isolate islands inside the country, because there are regions with a lot of demand and little generation, and other regions with a lot of generation and little demand. To do that would require separate transport.

Ah, yes, that happens.

Don't worry :-)

I don't understand. Surely the Spanish distribution system is pretty much like the UK one with maybe the transmission voltages different. The main super grid at 400kV and then various other big transmission lines at 275kV, 175kV and the lowest EHT at 33kV and circuit breakers so that local faults due to trees on the line or lightning strikes remain local.

There should be a hierarchy of bigger isolators all the way back up the chain to drop out as much load as is needed to regain control. UK splash up failed because they hadn't allowed for domestic solar PV when they tried to shed load and it was very sunny.

That may be the problem in Spain too. Failure at midday suggests oversupply and rising frequency rather than a power shortage.

USians can't imagine using so little electricity as is the EU norm. The maximum amount that you use seems tiny even to me in the UK.

Our 3kW kettle would blow your supply. Same in Japan.

I found a Wiki reference to the one my mate worked on 2.25GW :

A southern Nimby is worth ten in the north. UK PLC is run entirely for the benefit of Londoners and residents of the Home Counties.

We generate insane amounts of electricity in the north (and always have done since coal fired power) now mostly offshore wind and in Scotland on shore. The links to the south where it is needed are sadly lacking.

NESO couldn't run a piss up in a brewery.

Of course a big generator can't sink power. If a few million people are incentivized to have rooftop solar and to get paid to push it back into the grid, and there's no way to stop them, things will get bad on a sunny afternoon.

I'd imagine that 10 or so square meters of PN diodes, out in the fresh air, could dissipate a bunch of power. Certainly more than the panel usually generates.

The controllers just aren't set up to work in that direction, nor is there usually a way to tell them to.

Rooftop solar is kind of silly.

About 30% of the roof-tops in Australia have it. It's a profitable investment. Adding a Tesla Powerwall or the like makes it a bigger investment, but about 40% of the most recent installations have them - the extra profit is worth having.

Silly people don't tend to have that kind of money.

Politicians don't design power systems. They subcontract that job to engineers. They may not give the work to the right engineers, but greenie politicians are unlikely to be any worse at picking contractors than any other kind of politician.

Doesn't sound as if they'd given the job to a good engineer.

In Australia, the utilities cut the price they'd pay for excess current generated by a roof-top solar set-up very early on.

About 40% of new roof-top solar installation in Australia now include a Tesla Powerwall or a similar big battery, so the household can store excess energy until they need it. Not paying the utility rates for power that you use at night lets you pay off the whole installation over about seven years. Not dramatic, but well worth doing if you have the capital.

Some systems do put power back into the solar cells, specifically if it is sunny but the panels are covered with snow. If it is sunny enough to be worth it, the panels can be electrically heated for a short time so the snow slides off and they can generate more than enough energy to repay what was used to loosen the snow.

You could also use the PV modules as a load to dump energy if this is ever necessary to stabilise the grid, though doing so for long periods when it is very sunny might overheat them and shorten their life. At night it would work great though, (presuming someone else is paying you to use that power!). Conversely, solar panels run significantly cooler when delivering maximum power to the load, since these days they are nearly 25 percent efficient so when you disconnect the load, the extra energy has to go somewhere.

Network grade batteries, none, I believe. There are plans for water pump/generators. Some of the islands do have them.

It seems that solar panels and wind farms mostly have the type of inverter that follow the shape of the voltage already in the grid, with detection to bail out if things go nuts. There is the suspicion that this was at least part of the problem.

But there is another type of inverters that force the shape, ie, simulate inertia.

And of course, large batteries on the network can be used to simulate very large inertia, much larger than mechanical generators. Minutes vs seconds, perhaps.

Things happen.

Dunno.

I'll try to expand some information, for you and Martin.

In Andalucia and Extremadura (south and west of Spain) there are lots of rural areas that can accommodate huge solar plants, so lot of generation. On the other hand they don't have much of industry (not traditionally developed areas), so not much of demand (relatively).

On the other hand, Madrid (centre of Spain) and Cataluña (north-east) have a lot of industries and less solar/wind generation.

Nuclear generators are also mostly in the periphery, near the sea or big rivers. Not in the very densely populated Madrid (map here:

Where do they get the energy from?

Solar panels and wind farms collect energy from sun and wind. To "force the shape" of the output waveform you might need a single cycle's worth of energy in a short term store, such as a capacitor.

The distinction between a capacitor, a super-capacitor and a battery is essentially how long the energy is stored - you can store more energy per unit volume as you move towards the battery end of the series. The internal resistance goes up along the same axis.

To have a bit of margin to regulate, PV installations will have to either run somewhat below the bleeding edge, or to store a bit of energy in local batteries.

Jeroen Belleman

That doesn't make sense.

In general it is not possible to centrally separate out residential solar from the residential loads so all they will see is a 60MW load, the 40MW local generation is invisible to them and is only apparent as a reduction in the load.

Most run at the MPPT point, so have no reserve to save the grid. And a lot of cloud cover or still wind will precipitate the very crisis that needs reserve.

It doesn't make sense to me for a multi-country grid to depend on "a bit of energy stored" in household batteries and inverters for emergency reserve power.

As the grids get greener, expect power to get less reliable and much more expensive. Hopefuilly the USA will use more NG, build more pipelines, and drill, baby, drill.