The cleanest coal plant in the world is under construction, and although most people in our field say carbon capture and sequestation is too expensive to be realistic, this techology looks pretty interesting.
A clean coal demonstration project, The Texas Clean Energy Project (TCEP), announced the first power purchase agreement for a commercial-scale carbon capture plant in the US.
CPS Energy, the largest municipally-owned utility in the nation, will buy 200 MW of power a year from TCEP when it comes online in 2015.
The Texas Clean Energy project is the first in the US to combine Integrated Gasification Combined Cycle (IGCC)and carbon capture and storage technologies.
Using IGCC, the plant will emit less than 10% of the carbon produced by a comparable conventional coal plant, and less than 25% of a high-efficiency natural gas plant, says the Department of Energy (DOE).
It will capture 90% of the carbon it produces, as well as 99% of sulfur dioxide, 90% of nitrogen oxide, and 99% of mercury.
Instead of burning coal, it will be sealed in a gasifier – an airtight chamber that allows in only controlled amounts of oxygen. When oxygen is minimized, the coal bakes rather than ignites and enough heat and pressure is created to squeeze hydrogen and carbon monoxide fom the coal. Those gases are then processed into synthetic gas, or syngas.
Water vapor is then added to the syngas, which chemically reacts with the carbon monoxide to create more hydrogen and carbon dioxide. When impurities are removed from the gas it’s separated into pure streams of hydrogen and carbon dioxide.
The hydrogen is used to power a turbine to generate electricity and its carbon-free exhaust heats water to generate steam that’s fed to a turbine to produce even more electricity.
Of the nearly 2.9 million metric tons of carbon dioxide to be captured annually at the plant, 83% will be used for enhanced oil recovery and the rest will be used to make urea, which has many industrial applications.
DOE’s Clean Coal Power Initiative is funding $450 million of the $2.4 billion plant.