Saturday 21 August 2010

An Electrifying History

By Richard Morley.

In 1919 Madrid’s first underground Metro line began running from Cuatro Caminos to Sol and for the next two years there was very little rainfall. How are these two facts connected?

Very easily if you realise that the Metro then was a green as it proclaims itself to be today. It drew most of its electrical power from a hydro-electric station north of the city. This was not unusual. At the beginning of the 20th Century, 40% of Spain’s electricity was generated from water. It’s difficult to do this if it doesn’t rain.

A hundred years later, Spain struggles to generate 25% of it’s electricity from Hydro-electric plants, and has long since stopped relying on it as its only source of power.

But if you are running a metro system that needs a regular, steady, reliable supply of electricity, what do you do? You throw your green credentials out of the window and build Spain’s largest oil fired power station.

By 1923 line 1 had been extended from Sol, though Atocha and out to Puente de Vallecas, taking it past Pacifico, which at that time was not much more than an industrial site, making it a perfect place for a noisy, dirty power station.

And by no coincidence at all, 1923 was the year the new power station came on line.

Led by two engineers, José Maria and Manuel Otamendi, three very large generators, originally made in Switzerland were shipped from Germany and installed on a site about two hundred metres from Pacifico Station. The generators were so large that the building in which they are housed had to be built around them. Incidentally, the company who built the generators, Sulzer Brothers, still make similar, although more modern, machines today.

The building that houses the machinery is really something. It was designed by no lesser person than Antonio Palacios, more famous for the Palacio de Communications at Cibeles, the García Barbón Theater in Vigo and the construction of the first Metro stations. His work for the metro is still visible in the Stations of Tirso de Molina and at the Metro Museum at the old station of Chamberri. It was he who proposed that to combat the publics fear of being underground, the underground stations should be as bright and spacious as contemporary technology allowed.

More used to designing on the grand scale as befits his name, the edifice he constructed around the three generators is rather grand. After all, this is no more than a large shed. It is called “El Nave de Motores”, and “nave”, when it doesn’t mean “ship”, signifies a warehouse. (Also think of the nave, the largest, central part of a church – obviously from the same Latin root.) From the terracotta floor tiles, inlaid with white glazed delineation lines around the machinery, to the copper glazed white and floral olive wall tiles inset with opalescent piping, it strives to be more than it is. Somehow it contrives to be both work-a-day and beautiful. A cathedral to power. The art deco flow of stair banisters up to the control deck is quite striking.

And it up there, on the control deck, the “nave” meaning “warehouse” takes on its other meaning as the platform, with its dials, switches, rheostats and banks of warning lamps, looms like a ship’s bridge high above the three giant generators on the deck below.

And that of course is what its all about: the generators. Looking seriously like exhibits from the Industrial Revolution with their heavy black cast iron bodies, thick and intricate pipe work, gleaming brass fittings and exposed moving parts, these three 1500 horsepower motors each turned a gigantic rotor set with massive copper coils. Turning at a steady 150 revolutions per minutes those rotors were capable of generating much more than a megawatt of power. Each!

One Thousand, One Hundred and Ten Thousand Watts. That's powerful!

I was told that the engines are similar to those that powered the Titanic. These are quite smaller than those that drove the great ship to its icy demise, but that is not to diminish their bulk. They tower six metres above the shed’s floor, but like the iceberg that toppled the Titanic, much of the machinery is hidden below floor level. To get a close up photograph I stepped on a metal plate that surrounded one of the beasts and was immediately warned off by a security guard who politely informed me that these plates and associated guardrails dated from when the generators were installed and would not stand today’s health and safety scrutiny and I was to get the hell off before I fell through and on to the hard concrete another four metres below.

Unlike the Titanic, these motors were fuelled by diesel. In its heyday, in what is now a nicely tended garden, stood six huge fuel tanks and I would imagine the motors would get though that fuel at a prodigious rate. But first they had to be started – and what a procedure that was.

First a small electric pump would compress air into two tanks. This air would be used to pressure the first, somewhat smaller, cylinder of the motor, which in turn drove compressed air and fuel into the other four. The compressed air would crank the pistons for a good five minutes before the machine would run by itself, taking a further few minutes to reach full speed.

With the cast iron, four metre diameter rotors, themselves so heavy a special, powered mechanism was needed to crank them during maintenance, now spinning at the correct speed, the forty ( or there about) coils spaced equally around the external rim would be excited with electricity turning them into magnets, which would now generate the output power in the heavy copper coils of the fixed stator meshed around them.

But the generators made alternating current electricity and the trains on the metro require direct current. In those days, and in fact until very recently, the voltage required was six hundred volts. The output of 15000 volts was first reduced in a series of transformers and then rectified into DC in a device called a rotary converter. These machines, one for each generator, stood two meters high and whizzed around at a fantastic rate. As the alternating voltage crossed from positive to negative or vice versa, a hundred times a second, flashing banks of switches would move from one position to the other, driving only positive current into the fat cables that carried the DC power away through a tunnel to the metro line a couple of hundred metres away and then distributed throughout the system.

The three rotary converters and the switches that clicked so fast.
The massive motors would rumble, switches would click and buzz, the rotors would spin. Imagine the noise!

I will retell a story my guide told me. A few years ago when the Nave del Motores was being renovated and turned into the museum it now is, the engineers working on the project thought it would be a good idea to start one of the generators. As I mentioned at the start of this article, when the power station was built this area of Madrid was an open industrial landscape. Now it is hemmed in on all sides by tall residential apartment blocks. Within five minutes of the great machine lumbering into action the police were banging on the door saying some neighbours were complaining that the noise was unbearable, windows were rattling in their frames and the buildings were shaking as if an earthquake was in progress. The motors have never been started again.

Three giant motors burning so much fuel would generate almost as much heat as electricity. The motors were water cooled with the water flowing through fat pipes to a cooling tower outside. The tower has now gone, replaced by a visitor’s centre, but the old water tanks are still there.

It is also interesting to note that this complex was run by just five people. Four engineers and the “Woman who watched”. This woman’s job was to monitor a bank of warning lights and, via a switchboard, to pass on the warnings. She did this because there was just too much noise for normal, vocal communication, so some form of electronic semaphore was the solution.

Above the tool board are the four warning panels watched by "The Woman". Note the shiny tilework and the copper glazed inlay.

I mentioned that diesel was the fuel of choice. But not for the politicians. After the Civil War Franco decided that Spain should be as self-sufficient as possible. The correct term for this is an “Autarky” and this period continued until the late 1950s when outside trade was once again allowed. Given that from 1939 onwards the rest of Europe was going though a major upheaval that made great demands on fuel supplies, Spain was forced to look to itself.

The country’s oil reserves were, and are, miniscule, but in Puertollano (Ciudad Real), Lalames and Punta del Cuerno (Asturia), and Rubielos de Mora, (Valencia), lay sizable quantities of oil shale, an organic rock from which oil can be obtained, albeit after a more complex and expensive refining process than crude oil.

And so the power station at Pacifico was reconfigured to use this fuel as well. However, the generators still had to begin running with diesel as the synthetic oil did not pack enough punch, and then switch to the lesser fuel.

According to Elena San Roman and Carlos Sudria in their article, “Synthetic Fuels in Spain, 1942-66: The failure of Franco’s autarkic dream”, published in 2003, the Spanish government allowed the Nazi supported I G Farben company of Germany to develop a source of fuel from the oil shale deposits. Given that Germany desperately needed fuel for its war machine, I doubt Farben’s involvement was purely altruistic.

After Germany’s defeat ENCASO (Spanish National 'Calvo Sotelo' Company) and REPSOL ( Spain’s national oil company) set up a research centre in the Embajadores district of Madrid to utilise oil shale from Puertollano for both fuel and fertilizer.

Not far from Puertollano, eighty or so kilometres west, lies the small town of Almudén, home to the world’s greatest deposits of cinnabar from which we get mercury. Almudén has supplied the world with more mercury than anywhere else. Mined since Roman times, it is estimated that around 25,000 metric tons of mercury have been produced there over the subsequent 2000 years. The mine closed just a decade ago caused by a combination of low prices and the dangerous nature of the material. A couple of centuries ago the mines were worked with convict labour and it is recorded that nearly a quarter of the prisoners died before their sentence was complete due to hydrargyrosis, or mercury poisoning. A man working with the “roasting” process, which extracted the mercury from the cinnabar, was thought to have a life expectancy of just six months.

What’s that got to do with power generation for Madrid’s metro? Outside the generator shed stands a large metal drum with a bunch of large electrical connectors around its circumference. This was the device that made the old rotary AC to DC converters obsolete. It is a mercury arc rectifier and the size of it scares me.

In my apprenticeship many years ago we played with smaller versions of these devices where a negative cathode is drowned in a pool of mercury and then heated. The current passed through super-heated mercury plasma to a positive anode. It would handle very large currents, but the mercury vapour was deadly. That didn’t matter (!), it was all contained in a glass bottle – which had been known to break. Ooops!

But the rectifiers we played with as apprentices contained only tiny amounts of mercury and in fact we would steal the mercury from old ones and watch as the “quicksilver” rolled and amalgamated in drops on our work benches during lunch hours. Health and safety then had not reached the stupefying (self-)importance it has now.

The rectifier from the power station would have contained huge amounts of mercury, which was why it was contained in a strong steel drum with its two halves firmly bolted together. But still it was regarded as being too dangerous to have inside the closed confines of the generator shed and is now consigned to the garden of the museum. And hopefully, most of the mercury has been removed.

Mercury Arc Rectifier

The demands of power made by the metro system would vary throughout the day, but it would have been impossible to start and stop the generators as needs required, so beside the shed stands an almost castle-like building which used to contain banks and banks of batteries. Now I have never seen a six hundred volt, high current battery. I do remember the rows of fifty-volt open accumulators found in telephone exchanges in the UK many years ago, when connections were made mechanically. The air was filled with the acrid stench of sulfuric acid which really got up your nose. So huge batteries that could power a several trains at once must have been something to behold.

Today, that castle-like building contains the offices of the metro workers’ union. You remember, those people whose strike caused so much disruption a few weeks ago. So know you know where they live!!

The Pacifico power station did more than just run the metro. During the civil war it supplied power to the rest of the city and continued to do so to minimise power outages in later years. At the time of its construction it had the largest output of any power station in Spain. At full power it could churn out nearly five Mega watts. That’s enough to power 50,000 toasters like the one in my kitchen!

By 1972 the metro had expanded to five lines and more were on the way. Residential blocks were beginning to encroach on the Nave and alternative sources of power were now readily and reliably available. After fifty years of service the power station was decommissioned and basically left to rot.

In 2006 it was decide to renovate the nave in conjunction with the old station at Chamberri, which had closed in 1966 and to open them as monuments to the history of the World’s Best Metro.

The Metro Museum at Chamberri.

And once again the Metro strives to be green. Its website states its environmental responsibilities. But that doesn’t really go far enough explain that now the trains actually put energy back into the system whenever they slow down, that the trains are constructed from the lightest materials to use less power. It continually innovates new technology to become more efficient.

Just two blocks away from the Nave, the metro station of Pacifico is the first to benefit from the use of geothermal energy to create a better environment.

The Nave del Motores is in the Calle de Valderribas, 49, just a five minute walk from Pacifico metroon line 1 or slightly longer from Conde de Casal on line 6. Depending on your nerdiness the visit could take between 45 minutes to a couple of hours. The museum is open Tuesdays to Fridays from 11am to 7pm and at weekends and festivals from 11am to 3pm.

I would like to thank my guide, Amelia, who somewhat surprised to suddenly have to speak English for half an hour, did a wonderful job of explaining the museum, and the job it used to do, to me.


  1. Totally neat! Thanks for sharing this. I look forward to visiting sometime!

  2. A wonderful account and it very much reminded me of a trip around the Reading power station in the early 60s, which was still running rotating machinery built for the Crystal Palace exhibition (1851/52). And those mercury arc rectifiers, weren’t they something with their blue glow!!

    Definitely, your account has added yet another place that I have to visit when I return to Spain – thanks for the info and for the memories.

  3. I read about this place when I visited Chamberri last year. It's definitely top of my list of (non-food) places to visit next time I'm in Madrid.