The power units generate power by burning fossil fuels (oil, natural gas or coal), to generates steam. The steam turns a tribune connected to an electricity generator. This process is called tribune combustion. Carbon is captured from power plants mainly in three ways: post-combustion, pre-combustion and oxyfuel combustion.

• Post Combustion Capture: It is applied to fossil fuel-based power plants, where after combustion of fossil fuels carbon dioxide is captured from flue gases. It is the most commonly used method for carbon capture. This process can be retrofit in older plants by installing a filter. It uses a solvent that absorbs carbon to help capture carbon when it travels up in the chimney. The solvent is heated and consequently, water vapour is released and a concentrated stream of carbon is left behind. 
• Pre Combustion Capture: It is used by fertilizer, chemical, fuel (H2, CH4) and power plants. This method partially oxidizes the fossil fuel. In the gasifier, carbon resulting from synthetic gas (CO and H2) reacts with steam (H2O) to form CO2 and H2. It is called a water-gas shift reaction (WGSR). The resulting carbon is captured from the exhaust stream and hydrogen is used as a fuel. Through this method, carbon is removed before combustion. 
• Oxy-fuel Combustion: In this method, fuel is burned with pure oxygen instead of air. This results in a gas mixture comprised of steam and CO2. Both are separated by cooling and compressing the gas stream. The captured carbon is then transported to sequestration locations. This technology is often referred to as “zero-emission” cycles as it captures pure carbon. A small fraction of carbon is produced during combustion and end up in condensed water form, which is disposed of appropriately. 

Once carbon is captured it’s transported through pipelines and vehicles to its storage location in forms of gas, liquid or solids. Carbon can be stored in two places underground and underwater. 

Carbon stored underground is found in liquid than a gas. It seeps in the spaces of porous rocks overlaid by permeable layer which is non-porous, known as geological sequestration. It is mainly used in the oil and gas industry to extract oil from depleted reservoirs. Basalt formation (volcanic rock) also helps in storing carbon. Basalt rocks are the most common types of rock, even the ocean floor is made up of it. When carbon is injected into these rocks, it turns into limestone. Other projects like CO2 sink and sleipner gas field is another ongoing project to test geological sequestration by injecting carbon into sandstones and seafloor.

 In addition to underwater storage, it is safe to dump carbon directly into the ocean at a depth greater than 11,482 feet. Here carbon is compressed into mushy material on the ocean floor.