What Is Clean Coal and Why Should I Care?

The term "Clean Coal" is being used to describe several different processes. Some are only new ways to try to remove pollutants from the smoke produced by burning coal. Some of these pollutants are sulfur (which combines with water in the atmosphere to produce sulfuric acid (acid rain) and mercury (which builds up in your system and can cause brain damage). Other technologies offer something completely different and it is on those that I would like to focus here.

The <a href = "http://www.futuregenalliance.org/">FutureGen</a> system is one that has received government research and development funding to the tune of millions of dollars and is on the verge of building a power plant in Illinois. In this system coal is not really the fuel used to produce electricity. Coal (or any other source of carbon such as charcoal or even <a href = "http://www.bioware.com.br/english/">torrified </a>cornstalks and straw).

In this process 1000 degree steam is passed over coal in the absence of air. This causes a chemical reaction between the oxygen in the water molecules in the steam and the carbon molecules in the coal: 2H2O + C ------> 2H2 + CO2. The carbon dioxide produced is then taken out of the mix and the hydrogen (H2) is used to fuel the power plant.

There are many advantages to using hydrogen as the fuel in an electrical generator. One of these is that it burns much hotter than carbon does and so you need less hydrogen fuel than you would coal. Another consequence is that, because you use less fuel, you produce significantly less carbon dioxide than a normal coal plant.

Still another advantage is that when you burn hydrogen the product is superheated steam (2H2 + O2 ------> 2H2O). This steam can be used to turn the turbines that drive the generators in the plant with very few losses. In a traditional coal fired plant the coal is burned outside a vessel that contains water (a boiler) to create the steam needed to turn the generators. This means that much of the heat created by burning coal goes up the chimney and is lost.

The FutureGen system is therefore vastly superior to a traditional coal fired plant. It is the first large scale electrical generator which uses clean, renewable hydrogen fuel from water. Unfortunately the designers of this system tried to go too far too fast and proposed pumping the carbon dioxide that is produced by releasing the hydrogen fuel from water underground to sequester it. This sequestration plan is untested and has become the major sticking point of the whole project.

I think that this is unfortunate because even without the sequestration plan this plant is a huge step forward in our goal of ending our dependence on fossil fuels. Another unpublicized bonus with this system is that you could use the hydrogen fuel produced to run cars, trucks, trains, ships or any vehicle with an internal combustion engine. That's right, you can, in effect, run your car on coal (actually on hydrogen produced through this process) and since coal is still around a hundred bucks a ton or less that would mean that your hydrogen fuel would cost roughly .25 cents a gallon (a rough estimate).

There is a way to use a process very similar to this one with water and liquid hydrocarbon fuels as well and in that case you can produce your hydrogen fuel on board the vehicle as you drive. That process would increase your hydrocarbon fuel mileage by up to 60% and reduce your carbon dioxide emissions by an equal percentage. The tools necessary for us to cut our fossil fuel consumption and carbon dioxide output on a worldwide basis are there but we are just not aware of them or being told about them (whichever you like).