Understand the concepts of carbon capture and storage

Carbon capture and storage, or CCS, is a process we can use to reduce our greenhouse gas emissions by an estimated 10 gigatonnes -- 10 billion metric tonnes -- per year by 2050.

Rather than let carbon escape into the atmosphere in the form of Carbon Dioxide (or CO₂) when fuels like coal and gas are burned, CCS allows us to capture the CO₂ and store it for the long term.

CCS isn’t an answer to global warming. But CCS is important because:

• It’s a cost-effective approach to helping meet our emissions reduction targets.
• It’s versatile. CCS can be used not just at power generation sites, but also at high-emissions industrial facilities.
• The technology already exists, so we may use CCS processes globally to reduce emissions in the near future.

How CCS works

Carbon capture and storage is a three-stage process:

1. Carbon capture
2. Carbon transport
3. Carbon storage

1. Carbon capture

Three processes are used to capture the CO₂ emitted when fuels are burned.

Pre-combustion capture
Before the fuel is burned, it's turned into a gas. The CO₂ is separated from that gas, which is then burned to generate energy.

Oxy-fuel capture
CO₂ gas can be captured during the burning process, in the combustion chamber itself, if the fuels are burned in air enriched with oxygen.

Post-combustion capture
CO₂ can be captured after the fuel is burned, using chemicals to "scrub" the gases produced by burning the fuel.

2. Carbon transport

Carbon transport involves moving the CO₂ from the point at which it's captured to the place where it'll be stored.

To date, carbon has been transported using high-pressure pipelines, ships, trucks and trains.

3. Carbon storage

Carbon storage involves placing the CO₂ into the earth for the long term. We currently have three geological storage options:

1. Saline formations
2. Oil and gas reservoirs
3. Deep coal seams

CO₂ storage in other geological formations, such as basalt, may also prove effective where these options aren’t available.

Studies have shown that CO₂ injected into saline geological formations and oil and gas reservoirs remained safely stored without leakage, according to the Intergovernmental Panel on Climate Change.

What CCS Isn’t

There’s been a lot of talk -- and confusion -- about what CCS means for our emissions reduction efforts.

CCS isn’t:

• an excuse for ignoring climate change
• an answer to global warming
• synonymous with "clean coal"
• a way to keep people in unsustainable jobs.

What CCS Offers

CCS can help us smoothly and cost-effectively transition from fossil fuels to renewable energy sources.

Affordable emissions reduction

The International Energy Agency estimates that a total of 145 gigatonnes of carbon dioxide can be captured and stored in the next 40 years.

It's calculated that without CCS, the cost to halve global greenhouse gas emissions by 2050 would increase by 70%.

Yet the cost of proposed CCS project development between 2010 and 2050 represents just 6% of the total investment needed to halve emissions in that time, according to the IEA’s CCS Roadmap (pdf).

At-emission-point reduction

Fossil fuel, biomass and gas energy generation facilities have obvious potential for CCS technology, but there are many others.

Industries like pulp and paper, cement, chemicals and metals production and fuel transformation also offer possibilities for CCS.

A viable addition to the emissions reduction package

The technology already exists, and five commercial CCS projects are already operating in Norway, Algeria and North America.

With additional research, we may use CCS processes on a larger scale in the near future.

What questions do you have about CCS?