THE Australian government has announced plans to introduce a carbon price scheme forcing industry to buy a permit for each tonne of carbon dioxide emitted from July 1, 2012. A trading system, with the carbon permit price set on a market linked to other schemes overseas, could follow in three to five years. But the scheme is unlikely to achieve a reduction in carbon emissions from coal fired power stations. Tony explains:
The Carbon Price and Coal-Fired Power: A Note from Tony
We are being told that the introduction of this ‘Carbon Price’ will drive down the emissions of the offending greenhouse gas, carbon dioxide.
When those politicians stand at the podium and tell you this, it indicates only that they have no idea whatsoever of how electrical power is generated.
When I try and explain that what they say is incorrect, that is somehow perceived as my taking a political standpoint by disagreeing with the politics of either the Labor Government who are introducing this, or The Australian Greens Party, who are in fact driving the Labor Government on this matter.
To effectively understand what effect a ‘price on carbon’ will have on coal fired power generation, you need to understand how a coal fired power plant produces its electrical power, and once you can visualise this, then it becomes patently obvious that just placing a price on those emissions will not lower those emissions by any amount whatsoever.
Consider the electrical power that, er, ‘comes out of the hole in the wall’ at your house. It’s a regulated 240 Volts at 50 Hertz, (HZ) or 50 cycles per second, and that second part is what I want you to keep in mind here.
Here comes some pretty basic electrical theory here.
If you pass a wire capable of carrying an electrical current through a magnetic field, a small flow of electrons will occur in that wire. This flow of electrons is the flow of electrical current.
It then stands to reason that if the magnetic field was much larger, that current flow would be larger. The same applies for the wire. If there were a lot of wires, then the current flow would be larger. The same also applies for the speed at which those wires are passed through that magnetic field. The faster they are moved, then that current flow would be larger.
This is how electrical power is generate with a, well, generator, in the most basic of terms.
Let’s then scale it up.
Huge electromagnets are placed around a shaft. They are heavy and are made out of materials that best conduct high magnetic fields, so it’s not just the old iron magnets you remember from school. To further increase this magnetic field, these magnetic ‘cores’ have heavy gauge wire wrapped around them, and a current is then passed through these wires. This then intensifies that magnetic field, a classic electromagnet. To even further enhance that magnetic field, those cores can also be supercooled, as extreme cold also increases and intensifies that magnetic field.
Each wire wound magnetic core can be anything up to 6 feet in length. This ‘core’ is then attached to the shaft. Around that shaft there are numerous of these cores, an even number, (sometimes as many as 16 of them) because the same core directly opposite is the South Pole of the North Pole on the direct opposite side. These ‘cores’ are arranged around the shaft with respect to their magnetic polar orientation, North South North South etcetera.
Then, along that shaft other assemblies of these cores are placed. This final assembly of all those magnetic cores is called the rotor, and for a large scale generator, this rotor can be up around 80 metres in length.
You can see how the weight has become pretty substantial now. A large scale generator can weigh anything up to 1300 tons, and read that again, 1300 tons. That’s around 900 Toyota Land Cruisers.
The rotor, well, rotates.
In the housing around that rotor are wrapped huge amounts of wire arranged so that the rotating magnetic field, induces a current flow in them. This is the stator, and that is where the power that is eventually transmitted is generated.
Back to the rotor.
That immense weight now rotates at high speed inducing the current flow into the stator. That speed is 3,000 RPM, and just consider that for a minute 3,000 RPM. That’s 50 rotations every second, or 50 cycles per second, or 50 Hertz.
That’s the electrical power that ‘comes out of the hole in the wall’ at your home.
That 3,000 RPM has to be maintained and maintained exactly. It cannot go up or down from that speed at all, because the electrical power it supplies must be at that exact regulated frequency, 50Hz.
So now, you must drive this 1300 tons at that 3000 RPM. That’s 1300 tons rotating 50 times a second.
Snap your fingers and then snap them again. 1300 tons and 50 rotations.
Consider the generator (really an alternator) in your car. It produces all the electrical power your car needs. It is driven by a fanbelt attached to your car’s engine. The engine drives the generator.
The same applies here.
To drive that huge generator, a huge turbine is needed. This is a multi-stage turbine. It’s sort of similar to a jet engine turbine, with many blades around the shaft, and many rows of blades, and there are three separate stages of many rows of many blades, those rows of blades diminishing in size with the length of each stage.
This huge turbine can be anything up to 300 metres in length.
That huge weight of the generator is added to by the weight of the turbine as well.
To drive that turbine, in this case, the most efficient way is by using high pressure and consequently very high temperature steam.
That steam is ‘generated’ in a huge boiler.
The high pressure steam drives stage one. Some of the steam is then diverted straight back to the boiler, and the remainder goes to stage two, where again some is diverted back to the boiler, and the remainder to stage three, and again, some steam is diverted back to the boiler, and the remainder goes to the pond under the huge cooling towers where you see that ‘white stuff’ rising from the top, that being just cooling steam. This is the classic three stage steam turbine.
To generate that immense requirement of steam, a supercritical furnace is required to generate the immense heat required to make that steam.
This furnace uses coal as the fuel.
Crushed coal is fed into the furnace, and here’s where people have no concept of the amounts needed for a large scale coal fired power plant.
On this scale, for around a 2,000 MegaWatt (MW) plant, and they would typically have anything from 2 to 4 generators, some more, depending upon the size of the generator, the amount of power it can produce.
The amount of coal needed for something like this is around 6 million tons per annum, and work that out. It comes to around one ton of crushed coal being burned every five seconds.
Now, each ton of coal produces 2.86 tons of CO2, and that’s not complex science, but basic first year high school science.
Each atom of carbon combines (in the furnace) with two atoms of oxygen (CO2) and oxygen is slightly heavier than carbon, virtually tripling its weight, and as coal is basically all carbon with other elements in it as well, then that multiplier is in fact 2.86.
So, 6 million tons of coal burned each year produces 17.2 million tons of CO2, that direct target of this proposed ‘carbon price’.
The ‘people’ who operate the plant have to buy that steaming coal. That’s at around a cost of $100 per ton, so you can see that their costs just for the fuel are quite high. That price varies.
Hence, they operate the plant as ‘leanly’ as possible with the coal they consume, knowing exactly how much is needed to keep the required amount of steam up to the turbine enough to keep driving that generator at the exact 3000 RPM.
Because of the immense weight, a generator like this cannot easily run up and down in speed, well, it has to remain exactly at that 3000 RPM anyway.
The only time it runs down is for scheduled maintenance, one generator at a time, so the furnaces still need to be fed with coal to keep the others running. Before running it down, that power it provides to the grid is turned off, and then the generator runs down, never completely stopping as that immense weight could bend the shaft, making the generator then inoperable.
When that power is removed from the grid, other plants, mainly natural gas fired plants have to run up to provide the power that has now been removed from the grid.
So, that amount of coal that the plant burns is exactly regulated, because the plant must run at such exact tolerances.
So, when a politician stands at the podium and tells you that placing this ‘price on carbon’ will drive down emissions like those from these coal fired power plants, this shows me specifically that they have no concept whatsoever about how a plant of this nature works.
The plant is either running at its full production or it is not running at all. There is no middle ground. They cannot consume less coal, hence emit less CO2.
The introduction of this ‘price on carbon’ in this case is the most blatant grab for money from a target that cannot reduce what it emits, at any time.
Do not allow yourself to be taken in by warm and fluffy statements that this is for the good of the environment, or that imposing this ‘price on carbon’ will drive those emissions down, because it will not.
These politicians seeking to introduce this can only be one of two things. They are either lying outright, or they are hopelessly misinformed. It has to be one or the other, and either way it proves conclusively that they are misleading the public they represent.
When you understand how a plant of this nature works, then it becomes patently obvious that this is only about one thing.
This plant must burn 6 million tons of coal to operate at its capacity of delivery of electrical power. That coal consumption produces 17.2 million tons of CO2. This large scale plant, at Ross Garnaut’s figure of $26 per ton, will now see an increase on their bottom line of almost $450 million per year.
They cannot burn less coal.
They either pay that $450 million extra, or stop completely, and if they pay that extra, that will then be passed directly down to consumers.
There are 8 of these large scale plants in Australia, and 15 medium sized plants as well. All of them burn an exact required amount of coal, because the electricity they provide just has to be there.
What I have said here has nothing whatsoever to do with a political point of view.
These are incontrovertible facts, that even when explained like this, they will still be called into question by people with a political agenda.
To read more from Tony scroll and click here: http://jennifermarohasy.com/blog/author/tony/