My post about Why Hydrogen Powered Cars Will Never Work has received a record number of comments. Some of them suggested that carbon geo-sequestration (storing carbon-dioxide at high pressure under-ground) is the solution to the climate change problem. The idea is that you can mix natural gas or coal gas with steam at high temperature to give carbon-dioxide and hydrogen. Then the carbon dioxide gets stored under-ground while the hydrogen is used for relatively clean fuel.
Beyond Zero Emissions has produced a media release about the fallacies expressed in the FutureGen document promoting so-called “clean-coal”, the best content is in their PDF document titled FutureGen Conceptual Design Retort. Note that I did some research to support the preparation of the retort, I am not referencing them to support my arguments but as background information.
One overwhealming problem with geo-sequestration for coal based power plants is that it is significantly more expensive than the current coal-fired power plant design. Currently the price difference between coal power and wind power is quite small and there are several technologies that are almost ready for production which will decrease the cost of wind power, it is expected that before so-called “clean coal” becomes viable (they are planning for the first production plants to go live in 2022) the cost of renewable energy will be lower than the current cost of coal power. There is no reasonable possibility of “clean coal” being cheaper than renewable energy.
The underground reservoirs that could be used for storing CO2 currently contain brine, which can contain toxic metals and radioactive substances (according to the Bureau of Land and Water Quality in the US). If toxic and radioactive substances need to be pumped out to make room for CO2 then it’s hardly a clean process!
The US Geological Survey has an interesting page about volcanic gas. Apparently it’s not uncommon for small animals to be killed when CO2 forms pools in low lying areas. If (when?) CO2 escapes from geo-sequestration the same might happen with humans. They also have a page about CO2 killing trees at Mammoth Mountain! Before I read this I never realised that plants could be killed by excessive CO2. Apparently tree roots need oxygen and CO2 in the ground will kill them. The release of 300 tons of CO2 per day killed 100 acres of trees. The FutureGen trial power plant is designed to support sequestration of over 1,000,000 tons of CO2 per year (that is over 2,700 tons per day). If it leaked at 1/9 that rate then damage comparable to Mammoth Mountain would be the result. Note that the FutureGen trial plant will be a fraction of the size of a real coal power station so an escape of significantly less than 1/9 of the CO2 from a real sequestration plant would have such a bad result. It’s interesting to note that tents and basements are documented as CO2 risks, so I guess we have to avoid camping in areas near power plants!
What would happen if a large geo-sequestration project had a sudden failure? IE if the reservoir broke and all the CO2 erupted suddenly? We already have an answer to this question because such things have happened in the past. In 1986 in Cameroon 1.2 cubic kilometers of CO2 gas was released from a volcanic lake, that is 2,400,000 tons (or just over two years of output from the proposed FutureGen plant). It killed over 2000 people. What might happen if 10 years of output from a commercial scale coal power plant was suddenly released into the atmosphere?
As far as I know there has been no research on de-sequestration of CO2. If a reservoir is discovered to be unstable after 20,000,000 tons of CO2 have been stored in it, what will we do?
Geo-sequestration of CO2 makes nuclear power plants seem safe by comparison.
The technical feasibility of carbon sequestration depends on the geology. There are, in certain places, rock formations that have held natural gas for millenia; if there were no such places, then there would be no natural gas to be extracted. Similar formations could be used to sequester carbon dioxide for an equally long period.
One could make parallel comments about disposal of nuclear waste.
M. Gregoire: If CO2 from coal power plants was to be transported from power stations near major cities to rock formations that held natural gas (which often tend to be under seas or in different continents) then it would be a lot safer.
However transporting the CO2 increases the expense (in economic terms) and the energy loss. I believe that the general plan is to pipe the CO2 no more than a couple of hundred kilometers over land. I am not aware of any natural gas deposits that close to Melbourne or Sydney although I do acknowledge that some other cities may have natural gas deposits that could be used.
Again with nuclear waste the problem is safely getting it to the stable rock formation – with one additional complication that terrorists would be interested in stealing it and another being that much nuclear waste is solid and can’t be piped to it’s resting place.
The economics will vary from place to place. In some places, renewable sources of energy like wind, solar, or hydro-electric will be more cost-effective than coal, with or without CO2 sequestration. In other places there may be suitable rock formations relatively close to coal (or natural gas) fired power plants. Geo-sequestration should not be rejected out of hand, but evaluated for a given location.
M. Gregoire: The current aim for CO2 sequestration technology is that it be 10% more expensive than current coal-fired power stations by 2017. The latest research suggests that if we don’t get zero CO2 emissions by 2030 then the sea level will rise by 20M over the next century. Wind and solar power are viable now. We need to implement them now not wait 10 years for something that will probably be more expensive than renewable energy.
Creating A Carbon Economy
We have developed systems to make carbon sequestration profitable,
overcoming the main objection to it by creating a carbon economy
wherein it has real value and is not a waste..
The systems are under Patents Pending. You can read all about it
at our website at: http://www.geocities.com/profadrian/SCAF.html
Adrian Vance
Adrian: The section of your site about using CO2 enriched water to get CO2 into the soil seems like a bad idea. The observations at Mammoth Mountain suggest that CO2 is not good for a plants roots.
If you want to commercialise your ideas you might want to get your own domain name and web servers.