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Do we also know that Coal Combustion Products (CCPs)--by-products generated from coal-fired power plants—also help in saving the environment? Fly-ash, a by-product of coal can be used to substitute or supplement..

12 Jun 2013

By Rakesh Neelakandan
I don't know if you would go bongers after learning this, especially if you are a hell-bent renewable energy fan: 250 tons of coking coal are required for the manufacturing of an offshore wind turbine and 150 tons of coal are used in the production of an onshore wind turbine ! Now, you already know that burning of coal is contributing significantly to global warming and renewables have been lauded as an answer! (Of course, the wind turbines as and when they churn out electricity may offset the quantity of coal present in them by generating clean energy.)

The reason behind the presence of coal in wind turbines is pretty much simple. Steel is used in the production of wind turbine even as 85% of wind turbines world around is installed on steel structures. Besides, steel as a commodity represents 80% of all the materials used in the creation of a single wind turbine!

“Why steel?,” one may ask

Steel is deemed to be one of the most efficient construction materials ever invented with the highest strength-to-weight ratio of any materials that we use commonly in our day-to-day lives. Besides, the commodity is durable by an astounding manner, one reason why it is used in constructs ranging from bridges to viaducts to rail roads.

Well I cannot resist adding that coal is used in giant volumes in the manufacturing of steel. Coal is not only a raw material in steel production, but a fuel too when it comes to making of steel.

If steel is manufactured through the integrated steel making route (based on blast furnace or oxygen furnace), to produce one ton of crude steel, one may have to pour 770 kilogram of coal, 1400 kilogram of iron ore, 150 kg of lime stone and 120 kilogram of recycled steel into the furnace.

But if one takes the the electric arc furnace route which rely on recycled steel and electricity, only 150 kilogram of coal is required to produce one ton of crude steel.

If coal finds application in the steel sector, can aluminium be far behind?

A highly energy-intensive process, coal accounts for over 50% of power mix employed in the production of aluminium globally.

Aluminum is the most widely used non-ferrous mineral and is light weight, strong, recyclable and with resistance to corrosion. Employed widely in transport sector in the manufacturing of cars, the commodity is instrumental in reducing the weight of cars, trains and airplanes and thereby saving fuel use and preempting emissions.

It is estimated that new cars in Europe use on an average 132 kilogram of aluminium per car. Since aluminium has been preempting emissions, its use is going up substantially.

Now, if we take into account the case of Three Gorges Dam, the world's biggest hydropower station, the amount of concrete pumped into the construction of this mega-structure is estimated at 28 million metre cube which roughly translates into 2 million tons of coal use!

You know that concrete comes from cement. Close to 90% of world's cement is being produced with coal as a primary source of energy. At least 200 kilogram of coal is utilised in making 1 ton of cement. And 300-400 kilogram of cement is used to produce 1 cubic metre of concrete. Now, 28 million metre cube of concrete requires 2 million tons of coal! You do the math...

It is also interesting to note that half of world's cement is also produced in China! China also produces half of the world's bricks. Reports suggest that at least 42 million tons of coal were used in Chinese brick manufacturing in 2005.

According to International Energy Agency, 628 kilogram of coal is required to produce 10,000 bricks in China. In India too, 25 million tons of coal is used on an annual basis to produce gigantic number of bricks.

Cheer coal or jeer coal?

In the beginning of this article we saw how coal is used in wind turbines, a clean energy thing. But do we also know that Coal Combustion Products (CCPs)--by-products generated from coal-fired power plants—also help in saving the environment?

Fly-ash, a by-product of coal can be used to substitute or supplement cement in construction! And cement, as we have seen, is a vital ingredient in the production of concrete, second only to water in total volumes consumed yearly. It takes 200 kilogram of coal to produce 1 ton of cement.

Now, would you cheer coal or jeer coal?

I would leave that to you, but would also suggest reading Milton Catelin, Chief Executive, World Coal Association in this regard when he says in a blog post:

“Perhaps it’s time to think about a different approach to GHG (Green House Gas) mitigation. Let’s acknowledge the important role played by coal, stop focusing on how to cut coal usage and really focus on how to cut GHG emissions. If new coal-fired generating capacity added between 2000 and 2011 had used best available technology, cumulative emissions of CO2 over that period would’ve been reduced by almost 2 gigatonnes. This is three times the expected effect of the Kyoto Protocol”

[I have relied heavily on Coal Matters: Coal and Modern Infrastructure fact sheet brought out by World Coal Association for the statistics provided in the article.] (rakesh@commodityonline.com)

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