In Australia Clean Coal has been hotly debated. It's rejected by many as a tool to divert greenhouse attention away from the coal industry. Most skeptics of clean coal have not thought through the motivation of the clean coal people. Those that have given it thought, believe its either a way to buy time for the industry until the climate skeptics win (a very unlikely event even if temperatures plummeted and the Arctic refroze tomorrow). Or that the industry is trying to hang on until a crisis forces governments to buy them out of the sector with large compensation packages. That may happen.
In reality no scientist or businessman advocates a technology that he or she believes will not work. The advocates of clean coal are genuinely seeking an answer that is a win win solution for both coal and climate. All genuinely believe that coal power will and must continue into the future as a viable energy technology. That our civilization is built on the cheap energy of coal and oil. Many in the green movement also believe this idea: arguing that the era of cheap energy is gone and with it global trade, travel and western wealth will all cease [or even be banned].
The coal advocates costing of wind and solar may be out of date. However as long as coal is cheaper than unsubsidized renewables they will be unconvinced by the arguments for renewables. They are also acutely aware that the third world can't afford carbon taxes or to pay subsidies of any kind. However China and India still can afford dirty coal.
The challenge then is not simply to forcibly replace coal but to make all energies as cheap and easy as coal or make coal as clean as solar. Given the global growth in energy demand we need to do both.
Australia has several very useful projects in coal gasification including Solar enhanced pyrolysis of coal to gas, hydrogen production with CO2 capture. Deep geological sequestration experiments are under way in Victoria.
I believe geological sequestration will never be permanent because the CO2 is already a resource thanks to Carbon sciences. http://www.carbonsciences.com/01/index.php This Company wants to convert CO2 into man made chalk and plaster. Artificial carbonates made from mine tailings and CO2. The process is cheap and pays for itself and the carbon is immobilized for millennia with no risk. This and the technologies outlined below produce a powerful tool that can be used on the large scale within a few, 1 to 8 years. We need not wait for 2025!
Many have noted that money is being pulled from some clean coal projects world wide. This is not because governments have given up on clean coal but is because some projects are already obsolete. In the USA two of the discontinued projects were related to sulphur and mercury respectively; not CO2 related at all.
Clean Energy Systems has a prototype technology at a very low cost. http://www.cleanenergysystems.com/. It’s unlikely that they are either overstating their technology or understating the cost of their burner; particularly if it can be mass produced. This device burns Coal slurry in pure oxygen in a burner derived from rocket technology. It can be mass produced and if it can be retrofitted to existing power plants then, again, deployment could take a half dozen years instead of a quarter century.
I know enough about oxygen production to know that we can reclaim most of the energy used to produce it. Oxygen is produced by refrigerating air down to a low enough temperature that it liquefies or dissolves in various solutions. The cryogenic (but not liquid) nitrogen produced, if it is heated with waste heat will expand powerfully and can drive an auxiliary turbine. As I said reclaiming most of the energy.
Also if adequate oxygen storage is added we can use off peak energy from any source to make the oxygen thus any energy that would have been wasted is reclaimed, amplified and used to facilitate clean coal. There are also plans to create a huge fleet of hydrogen fuelled cars, buses and other vehicles. If you use electrolysis to make hydrogen you also make oxygen. For each mole of hydrogen you make half a mole of oxygen. Only a true fool would throw that resource away! It is essentially free in both monetary and energy terms. A clean coal plant can't make oxygen by electrolysis. Renewable energy would be needed; but its a perfect job for renewables that don't match the minute by minute demand of the grid.
If a powerplant can be built with these technologies integrated in, the debate would be over. The age of cheap clean coal would begin. It would be easy to convince the Chinese and India to accept and deploy the same technology in place of dirty coal and nuclear technologies.
Some solar, wind and biomass technologies will compete with such clean coal technology. Ausra, nanosolar, suncube and solar chimneys. Most established wind power will compete. General Compression and Flodesign should also be competitive with cheap clean coal. There are other technologies that will compete.
Only this clean combustion technology can, over time, reverse greenhouse gas emissions by burning biomass with the coal to produce energy and carbonate building materials. Eventually the coal oil shale, tar sands, etc will run out leaving only biomass and plastics to fuel these plants. By then solar will have matured to the point where it's ubiquitous, has integral storage and is as cheap as house-paint.
Those advocating renewables need to welcome clean coal into the fold, now that it has arrived, and call it what it now is, another renewable energy: Clean Combustion. It's good for ~1200 years on coal and much longer on oil shale or tar sands,and then almost forever on biomass and plastics garbage.
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