The Limitations Of Renewable Power (Part 1)

Posted on Tue 08/25/2009 by


Turbine Generator deck for the Number One Unit at Diablo Canyon Nuclear Power Plant Facility. Image courtesy Jim Zimmerlin.

Turbine Generator deck for the Number One Unit at Diablo Canyon Nuclear Power Plant Facility. Image courtesy Jim Zimmerlin.

The above image is of the Turbine/Generator room for the Number One Unit at the Diablo Canyon Nuclear Power Plant Facility. If you click on the image it will open in a new and larger window. I have purposely kept the image at such a large size so some of the detail can be best seen. Approval to use this image was kindly given by the man who took the photograph, Jim Zimmerlin, (Jim Zim) and is one of the numerous  images at his Diablo Canyon Nuclear Power Plant site at this link.

UPDATE July 2011

At that site linked to, Jim Zimmerlin explains the safe operation of this plant, especially with reference to the recent events following the Japanese Tsunami at the Fukushima plant, and how, even though this plant is actually on the San Andreas fault line, it is completely safe, and Jim explains this very well, as this plant can actually stand up to an Earthquake even stronger than the one that happened near Fukushima. This first page of Jim’s is well worth reading. This is not hyperbole from an outsider like me here in Australia, but from someone who has been working at this plant since 1992…..TonyfromOz.

I have included this image to draw attention to the limitations that are currently inherent with those renewable plants that we are told will be the way of the future, if we are to proceed down the path of replacing coal fired power plants.

Over the more than hundreds of earlier posts, I have tried to show just how limited the power produced from these plants is. I have concentrated on the process itself, and with this series, I want to show you the physical limitations of renewable power.

Now, when I say process, I need to explain that a little better for those who have no real idea of just how electrical power is generated.

The best example I can use to show you this is the car that most of you drive. Turn on the ignition key without starting the engine. All electrical systems are powered up, but that power is being supplied directly from the battery. As soon as you start the engine, a belt drives the alternator. Once the engine is running, all the power is being supplied from that alternator, for everything that uses electrical power in your car. That alternator cannot work without something driving it, in this case your car’s engine via the belt drive. In every aircraft, the engine has a direct drive coupling to the alternator supplying power for all the aircraft’s electrical systems.

In subsequent posts, I will go in depth into each of the three of these renewable power methods, but for a short introduction, those renewable power processes are as follows.

Solar Photovoltaic. The Sunlight provides the process. Hundreds of small cells are connected together into panels, and those large panels are then connected together to increase the level of power supplied from them. The sunlight causes a flow of electrons in each of those cells to generate the power.

Wind Power. The wind provides the process. It causes that large three bladed propeller to rotate which then drives the generator through a constant speed device, similar, but more detailed than a gear box.

Concentrating Solar. This is also called Solar Thermal. Sunlight shines on specially constructed mirrors mounted onto stands that track the course of the Sun, and called heliostats. The focused Sunlight is the process. It heats a compound to a molten state. This molten compound is then used to boil water to steam to drive a conventional turbine which in turn then drives the generator to produce the electrical power.

So, they are the processes.

Let’s then look at the actual generator that produces the power. This is a technical thing and my task is to make it simple enough to be able to be understood by the ordinary person with no background in electrical power generation, so if there’s any electrical engineers out there reading this, then you guys be kind on me, because I have to break this down into as simple a thing as I possibly can.

When a wire conductor is passed through a magnetic field, a flow of electrons is generated in that wire. This flow is really small as you may imagine, so the larger the number of wires, and the larger the magnetic field, and the larger the number of magnetic fields, then it only stands to reason that a large flow of electrons will eventuate, this called a current flow, in turn electrical power.

(Three lines. Now why did my students find it so damned hard.)

Pass the magnet faster and a higher flow of electrons is generated.

So then, let’s get a whole lot of those magnets together. The best way is to make huge electromagnets. Wire is wrapped around special materials to generate that large magnetic field. That special material is called the ‘Former’. In modern technology these ‘Formers’ are made from superconductor material. Now that word of itself is often mistaken to mean something else. People think of a conductor as something that carries electrical current, ergo, a superconducter can then carry huge amounts of electrical current. In actual fact the word superconductor in this application is a material that can best conduct a huge magnetic field, in other words, to better concentrate that magnetic field. This magnetic field is also stronger if that superconductor material is kept incredibly cold, and the most perfect huge magnetic field is obtained at zero degrees Kelvin, which really means nothing until I say that Zero Kelvin is minus 273 Celsius, or minus 460 Fahrenheit. Now, this temperature is almost obtainable, but impossible to keep at that low level. So, trade offs are taken into account, and that material is then kept at the coldest temperature that can normally be kept at for normal operation, while still able to produce a large magnetic field.

Now, a number of these magnetic ‘Formers’ are placed together surrounding a shaft, and placed in North then South, then North, around that shaft. These poles then rotate and induce a current flow in the nearby stationary vast number of windings of electrical wire. The rotating part is called, wait for it, the Rotor, and the stationary windings are called, wait for it, the Stator.

Now why I said all this is because I want you now to imagine that rotor. That’s an awful lot of a metal material with an awful lot of wire wrapped around it. Hence it amounts to a pretty large weight.

To produce those large amounts of electrical power, you need a huge rotor, and in those really large generators, (alternators really) you’re looking at weights in the vicinity of 250 to 400 tons, and some even heavier. Over the years, technology on all fronts has improved so much that the sizes, and the weights have come down considerably. Conversely, larger amounts of power can now be generated from larger sized generators.

Okay then, the canvas has been prepared. Lets add some paint.

Back into your car. You start the engine, and a belt drives the alternator to provide just the power needed for your car. That alternator weighs around 8 to 10 pounds maybe. Here we are looking at 250 to 400 tons. Something a bit more substantial than a belt is required.

A section of a steam turbine for a large power plant. Image courtesy of Siemens and is a Commons image..

A section of a steam turbine for a large power plant. Image courtesy of Siemens and is a Commons image..

For these large generators, a steam driven turbine is required. The image at the left here shows a man working on one section of one stage of a multi stage turbine that drives a large generator. Click on the image to open it in a new and larger window.

To actually drive all that weight, you are going to need an immense amount of high temperature and high pressure steam, and here you also need to consider that onto that same shaft we are now adding the considerable weight also of that turbine.

Now, having just said all that, this whole complex of turbine and generator has to rotate at high speed to produce even larger amounts of power from the generator. In the case of large complexes, the rotational speed can be between 3,000 RPM and 3,600 RPM. That breaks down to 50 to 60 times a second, so just count among yourselves there for a second or two.

Get an idea of the scale required now. Because of that huge content of required steam, large coal fired plants and large nuclear plants are the only ones that can actually produce steam on that scale required.

Now, go back to the image at the top and open it up in that new window, and then come back here and read this text. The generator is the white cylindrical complex behind the concrete electrical blockhouse on the end there. For some reference of scale, see the worker at the bottom left descending the stairs. This generator is around 36 feet long and around 15 to 20 feet across, half of it above floor level and half below the floor level.

Further back is the multi stage steam turbine with the large piping bringing steam to, and taking steam from the turbine.

This one generator can produce more than 1,000MW virtually on a continuous basis.

Nothing from the renewable sector can approach this level of power generation, and there is not even anything on the foreseeable horizon that could even come remotely close.

This, and this alone is why renewable power will only ever be of a ’boutique’ scale, albeit an enormously expensive boutique scale, and will never be able to compete with something of this scale.

In upcoming posts, I will deal with each of the three main renewable forms of power to explain their limitations, but after seeing something like this, it’s ‘case closed’ for my opinion.

This is why nuclear power plants need to be left on the table in this current debate, and why this lunatic rush away from coal fired power is just that.

Sheer and utter lunacy.