Germany Fired Up Over Clean Coal

MIT's Technology Review is reporting on the world's first coal-driven power plant designed to capture and store C02 emissions. "Vattenfall's small 30-megawatt plant burns the lignite in air from which nitrogen has been removed. Combustion in the resulting oxygen-rich atmosphere produces a waste stream of carbon dioxide and water vapor, three-quarters of which is recycled back into the boiler. By repeating this process, known as oxyfuel, it is possible to greatly concentrate the carbon dioxide. After particles and sulfur have been removed, and water vapor has been condensed out, the waste gas can be 98 percent carbon dioxide, according to Vattenfall. The separated carbon dioxide will be cooled down to -28 C and liquefied. Starting next year, the plan is to transport it by truck 150 miles northwest, to be injected 3,000 meters underground into a depleted inland gas field in Altmark. Ideally, in the future, the gas will be carried by pipeline to underground storage, says Vattenfall. "

Comments

how much power does it use

[maharg]

really, how much CO2 is generated in removing the nitrogen from the air used to combust the lignite ?

Re:how much power does it use

[DynaSoar]

really, how much CO2 is generated in removing the nitrogen from the air used to combust the lignite ?

None. The carbon come from burning the lignite, which is predominantly carbon, not from the air. A minor difference but a crucial one. The atmosphere contains 0.01 to 0.1% CO2, so your question is reasonable. But that being so, one should look to the rest of the process for the source, the answer being a BGO (Blinding Glimpse of the Obvious). Almost pure carbon + almost pure oxygen = a lot of CO2.

I'm interested in knowing where the nitrogen goes. If dumped in the air as N2 one would hope precautions against exposure to high concentrations are going to be stringent.

If turned into ammonia, it could be very useful in many manufacturing processes. But one then wonders where the hydrogen will come from. The water vapor produced in the combustion process is going to be recycled, if I read the description properly. Even if it weren't, 78% of the atmosphere is nitrogen, requiring a lot of hydrogen to bind to. Pulling it from water would eat up a lot of the energy produced. "Waste" hydrocarbons left over from cracking crude oil would be a good source.

Re:how much power does it use

[jimdread]

How can plants get us out of this mess? If the coal we're burning is made of dead plants, then plants got us into this mess, why can't they get us out?

The mess is caused by people getting carbon from outside our environment (deep underground) and putting it IN our environment. Plants did NOT get us in this mess.

If coal is made of plants, then coal is part of our environment. It's just part that has been turned into rock for a long time. Think about an atom of carbon in a hunk of coal. Imagine it being dug up and transported to a power plant and burned. It meets an oxygen molecule, and they join up to form a carbon dioxide molecule. That's pretty much all most people think about when they talk about global warming.

Here's the other part of the story that most people aren't thinking about. Instead of thinking about the atom of carbon in the present and in the future, think about its past. Think about where it came from.

The carbon atom in the hunk of coal was once a carbon atom in a plant, most likely about 300 million to 360 million years ago. That plant was turned into coal by being covered in mud and squashed for hundreds of millions of years.

The carbon atom must have been in the atmosphere or in the ocean in order to get absorbed by the plant. Those are pretty much the only places that plants get carbon dioxide. Therefore, carbon dioxide levels must have been much higher hundreds of millions of years ago. There had to be heaps of carbon dioxide in the atmosphere and in the ocean in order for all that coal and other fossil fuel to form. It didn't just get put there by aliens. Fossil fuels are made of dead squished up plants and animals. Coal, oil, and natural gas were once alive.

So the only way that all the carbon could have gotten into the coal, oil, etc, is if it was all in the atmosphere and the ocean, and then plants sucked it out, and deposited their bodies to form future coal. For example, atmospheric carbon dioxide levels during the Cambrian period averaged 4500ppm, over 10 times higher than current levels.

There is no way we could possibly get the atmosphere back up to 4500ppm. We would have to find, dig up and burn all the fossil fuel on the planet. And even that wouldn't be enough. We would also have to burn all the rock that has formed in the last billion years. Rock is made of calcium carbonate. The large sheets of limestone show that areas of the planet were covered with an ocean with a huge amount of carbon dioxide dissolved in it. That's how limestone gets formed. And limestone is partially solid carbon dioxide.

There is no need to keep a piece of paper forever. Suppose a ton of paper contains 250kg of carbon atoms. Suppose it takes ten years for a ton of paper to rot and convert into carbon dioxide. If you produce 100 tons of paper per year, you will end up with about 1000 tons of paper on hand at any time. That paper will contain 250 tons of carbon atoms. Those carbon atoms won't be in the atmosphere, because they are in the paper.

It's the same with coal. The only reason the carbon atoms are stuck in coal instead of being inside a puppy or a cotton plant is because they happened to be in those plants when they got buried. It's still a cycle, the same as paper rotting is a cycle. Burning coal is a natural process, which occurs even without human intervention. This should not be very surprising, since coal can be up to 100% carbon, and the atmosphere is 20% oxygen. Of course it will burn if the conditions are right. Maybe a lightning strike sets it off.

It's simply a balance problem. If we want to burn the coal, we need to store enough carbon atoms as something which isn't carbon dioxide in the atmosphere or the ocean. That's what this "clean coal" thing is about, they want to store the atoms underground. I'm just saying that we can store the atoms as clothes, paper, furniture, boats, houses, puppies

How much does it cost?

[swm]

What is the final cost of the generated electricity?
In $/KW-Hr?

Lake Nyos for next generation.

[Anonymous Coward]

What will exactly happen when the liquid CO2 will eventually warm up undergorund and then some future seismic event will open a crack ?

I hope this storage is somwhere in Sahara desert, not in the heart of densly populated Europe.

JAM

Solve the problem, for pete's sake

[cefek]

That's not the solution to the waste by-product problem. It only pushes it another decade, maybe two away. Storing waste CO2 underneath the surface is just asking for more problems. What happens if that gas is suddenly injected into the atmosphere? What happens is we all start living on, or maybe a couple of mile over, the ticking bomb?

Every energy production that has such a dangerous by-product is not the solution to our problem. Then again, we should think whether the hydrogen is. Don't want to sound like an asshole, but that water vapor those hydrogen-fueled cars produce is not going to vanish either.

Re:Solve the problem, for pete's sake

[FireFury03]

I'm a bit confused as to why sticking a small quantity of vitrified radioactive material under ground is a huge problem for the tree-huggers, but sticking vast amounts of liquefied CO2 in the ground is ok...

I'm all for diversification of energy sources, but I really don't understand why all the environmentalists are happy with this but not fission...

Re:Solve the problem, for pete's sake

[BlueNeutrino]

Storing CO2 into a depleted gas field is likely to last a lot more than a few decades. Hint: for how long did the natural gas stay in there? There are CO2 sinks which, given no emissions, can reduce CO2 concentration back to pre-industrial levels in a few centuries. Then it won't matter as much (if at all) when increased quantities of CO2 are released from their storage.

Re:Why store CO2?

[inviolet]

If it's pure CO2 they are capturing and storing, why don't they just release it into the Amazon rain forest?

Storing CO2 is not a viable solution, but giving it to the trees, who live on it and will convert it into 02, is!

Rainforests do not consume a net quantity C02. What carbon they do capture during photosynthesis is later reburned during respiration or released later during decomposition (e.g. bacteria, termites).

If rainforests were net consumers of CO2, then they would be accumulating a carbon store somewhere. This would take the form of vegetation mass (not increasing) or a coal seam somehow forming underneath all the tree roots (not observed). The carbon has to go somewhere if the trees are liberating any oxygen.

The only forests that do liberate oxygen and store carbon are young, growing forests. Mature forests are done -- they are in carbon equilibrium. Only young ones, which result from clearcutting and replanting, harvest carbon. This is why the US carbon credit program for forest owners will only pay out to folks who can prove that their forest is young growth.

And yes, I own a pine forest, and am sick of hearing about this crap.

Re:US should be fired up too.

[geekoid]

The coal industry ni the US has gotten waiver after waiver for our cleaner plants.
I dont believe they will ever implement an expensive technology unless someone puts a gun to their head. But they can't becasue what do you do if they just decide not to operate?

Not as clean as one would think

[DaMattster]

This is an interesting proposition but still does nothing to address the periphery problems associated with a coal fired power plant. For one, coal has to be mined and that usually entails destruction of land to get at the resource. Secondly, it takes significant amounts of energy to mine the coal thereby reducing its return. Thirdly, lots of energy is spent on transportation of the coal to the power plant itself. Finally, more energy is expended in trucking off the waste CO2. So my question is: Is this really a clean solution? More money and research should be plugged into hydrogen as a fuel for power generation. Hydrogen is ubiquitous whereas coal is a diminishing resource. Why not continue efforts into nuclear fusion for power generation?

Re:Before anyone gets REALLY "fired up" about this

[sampson7]

Yes and no. Coal plants are actually less size-dependant than you might think. The technologies tend to be similar, and even most 1,000+ MW coal plants are really just a series of 300-800 MW units within a shared space. As the article says:

In an initial three-year testing program, the Schwarze Pumpe pilot plant is expected to assess how components function together and exactly what proportion of carbon dioxide can actually be separated. Using the information gained, Vattenfall plans to scale up to a 300-to-500-megawatt demonstration plant by 2015 and to 1,000-megawatt commercial plants after 2020.

So they recognize what you are saying and have an actual timeline for addressing the issue.

Lastly, I just want to point out that coal plants are rather like vintage cars. Just as a do it yourself mechanics find working on an older car easier than working on a new computer car.

Brown Coal

[lobiusmoop]

It's all very well capturing the CO2 generated when burning lignite, but since it is the poorest form of coal with the lowest energy density, much more of it needs to be burned than with traditional anthracite (black) coal and so a lot more of the other air pollutants and ash are going to be generated as well, which seems like a bigger worry to me.

Re:steps

[fire5ign]

Actually, if it's radiation you're concerned about, being next to a dirty-ass coal plant would be a problem, because coal is slightly radioactive, and after ignition, some of that radioactive dust is emitted. see http://www.sciam.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste

Re:steps

[afabbro]

Not a popular solution, but we never heard the Roman Empire or ancient C'hin Empire worry about fuel shortages or melting ice caps. That's because there were only 1/2 billion people..... lots of room and fuel for everybody. Nature wasn't impacted.

You're referring to an empire (Rome) that depopulated the gamestock of northern Africa in order to stock its coliseums.

Re:steps

[blind biker]

There is a difference between natural gas and CO2: the latter is heavier than oxigen or nitrogen (i.e. air) and will stay in the low areas, potentially suffocating aerobic animals.

Could the CO2 escape in a massive way from these underground layers? It depends from case to case, but I am sure that I would feel much safer living on top of a deposit of natural gas, rather than CO2.