Carbon-capture-and-underground-storage "(CCUS)" tops the list of silly schemes "to reduce man-made global warming". The idea is to capture exhaust gases from power stations or cement plants, separate the CO2 from the other gases, compress it, pump it to the chosen burial site and force it underground into permeable rock formations. Then hope it never escapes.
An Australian mining company who should know better is hoping to appease green critics by proposing to bury the gas of life, CO2, deep in the sedimentary rocks of Australia's Great Artesian Basin.
They have chosen the Precipice Sandstone for their carbon cemetery. However the chances of keeping CO2 gas confined in this porous sandstone are remote. This formation has a very large area of outcrop to the surface and gas will escape somewhere, so why bother forcing it into a jail with no roof?
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Glencore shareholders should rise in anger at this wasteful and futile pagan sacrifice to the global warming gods. It will join fiascos like Snowy 2, pink bats and SunCable (a dream to take solar energy generated in NT via overhead and undersea cable for over 5000 km across ocean deeps and volcanic belts to Singapore).
Engineers with buckets of easy money may base a whole career on Carbon Capture and Underground Storage. But only stupid green zealots would support the sacrifice of billions of investment dollars and scads of energy to bury this harmless, invisible, life-supporting gas in the hope of appeasing the high priests of global warming.
The quantities of gases that CCUS would need to handle are enormous, and the capital and operating costs will be horrendous. It is a dreadful waste of energy and resources, consuming about twenty percent of power delivered from an otherwise efficient coal-fired power station.
For every tonne of coal burnt in a power station, about 11 tonnes of gases are exhausted – 7.5 tonnes of nitrogen from the air used to burn the coal, plus 2.5 tonnes of CO2 and one tonne of water vapour from the coal combustion process.
Normally these beneficial atmospheric gases are released to the atmosphere after filters take out any nasties like soot and noxious fumes.
However, CCUS also requires energy to produce and fabricate steel and erect gas storages, pumps and pipelines and to drill disposal wells. This will chew up more coal resources and produce yet more carbon dioxide, for zero benefit.
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But the real problems are at the burial site – how to create a secure space to hold the CO2 gas.
There is no vacuum occurring naturally anywhere on earth - every bit of space on Earth is occupied by something - solids, liquids or gases. Underground disposal of CO2 requires it to be pumped AGAINST the pressure of whatever fills the pore space of the rock formation now – either natural gases or liquids. These pressures can be substantial, especially after more gas is pumped in.
The natural gases in sedimentary rock formations are commonly air, CO2, CH4 (methane) or rarely, H2S (rotten egg gas). The liquids are commonly salty water, sometimes fresh water or very rarely, liquid hydrocarbons.
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