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Carbon capture and storage

The world’s energy demand is expected to double by 2050. At the same time greenhouse gas emissions must fall by at least 50% to conserve the environment, according to the Intergovernmental Panel on Climate Change (IPCC).

One vital step towards meeting both challenges is to capture and store carbon dioxide (CO₂) underground.

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Major industrial plants such as power stations, cement factories, refineries and chemical plants produce a large share of man-made greenhouse gases.

Greater energy efficiency will help reduce emissions. So will more renewable energy. But the single most effective way to tackle these gases is to capture them and store them safely underground in depleted oil and gas reservoirs or saline formations.

What are the benefits of CO2 capture and storage (CCS)?

Up to 55% of greenhouse gas emissions could be cut by 2100 through capturing and storing CO₂ underground, says the IPCC - opens in new window. And the International Energy Agency - opens in new window points out that the economic cost of stabilising these emissions through developing other technologies and energy sources would be considerably higher.

Is CCS safe?

CO₂ occurs naturally in the atmosphere and is not dangerous in low concentrations. When stored in a reservoir, the CO₂ would be held in place by the “cap” rock. This impermeable rock held gas in the reservoir for millions of years.

CCS is currently in the demonstration phase. If sites are carefully selected and managed CO₂ leakage rates could be less than 1% over 1,000 years, according to the IPCC.

The pressure is kept within safe limits to ensure that the reservoir and its seal are not damaged.

Sensors inside the injection system and within the reservoir can detect minute changes in pressure or CO₂levels, allowing engineers to act swiftly if needed.

What are the next steps?

Much of the technology used in CCS is proven.

Permanently storing the CO₂ underground is taking place in a number of joint industry projects – but many more large-scale commercial projects are needed, supported by government funding.

Governments must create the policies and frameworks – such as cap and trade mechanisms – to put a price on CO₂and allow CCS to become financially viable and widespread.