Atmospheric Carbon
Carbon exists in our atmosphere as carbon dioxide (CO2) and is released by a number of natural processes. Organisms, including humans, produce CO2 as they respire. When they die additional carbon (mainly in the form of methane) is released during decomposition. Volcanoes emit huge amounts of CO2 into the atmosphere when they erupt, as do forests when they burn.
There are also natural processes that remove carbon from the atmosphere. Plants take up CO2 and use this to create organic compounds during photosynthesis. The oceans are another big store of CO2, storing 50 times more than the atmosphere1.
Carbon emissions from fossil fuels
When fossil fuels are burnt, the carbon they contain is oxidised to form CO2 and is released into the atmosphere. Since the start of the industrial revolution the burning of fossil fuels has increased dramatically, increasing the total volume of CO2 in the atmosphere. Scientists believe that this has altered the balance of the carbon cycle.
What is meant by “clean coal”?
It’s not the actual coal that needs to be clean, it’s the CO2 from coal emissions that needs to be reduced. To that end the Australian Coal Association, through its more than $1 billion Coal21 Fund, is developing “low-emissions coal technology”, a better description for what’s often referred to as “clean coal technology”. The most prominent low-emissions coal technology is carbon capture and storage, which is designed to capture the CO2 released from the burning of coal and store it safely underground.
Why do we need clean coal technologies?
The world’s energy demand is expected to increase by 50% between 2005-20302 with coal as one of the biggest sources of this energy. Over 40% of the world’s electricity supply comes from coal3. Carbon capture and storage can provide a way to continue to meet these rising energy demands whilst reducing CO2 emissions from coal-fired power stations by over 90%.
Total World Electricity Generation by Fuel (2006)3
